ABCMdb

ABCC7 p.Ser1455*

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PMID: 10419506 [PubMed] Haardt M et al: "C-terminal truncations destabilize the cystic fibrosis transmembrane conductance regulator without impairing its biogenesis. A novel class of mutation."

No. Sentence Comment

19 Premature stop codons were as follows: Q1412X (A. Wallace and M. Tassabehji; ⌬70); S1455X and L1399X (⌬26 and ⌬82, respectively). Login to comment

PMID: 10562297 [PubMed] Moyer BD et al: "A PDZ-interacting domain in CFTR is an apical membrane polarization signal."

No. Sentence Comment

21 In addition, the CFTR mutant, S1455X, which lacks the 26 COOH-terminal amino acids, including the PDZ-interacting domain, is mispolarized to the lateral membrane. Login to comment
35 Toward these ends, we made chimeric constructs in which the green fluorescent protein (GFP) was linked to either wild-type (wt) CFTR or CFTR with truncations in the COOH-terminus (i.e., CFTR-∆TRL or CFTR-S1455X) and expressed these proteins in polarized kidney epithelial cells (MDCK) and human bronchial epithelial cells (16HBE14o-). Login to comment
37 In addition, the CFTR mutation S1455X, which lacks the 26 COOH-terminal amino acids including the PDZ-interacting domain, is mispolarized to the lateral membrane. Login to comment
52 pGFP-CFTR-S1455X encodes a GFP-CFTR fusion protein lacking the 26 CFTR COOH-terminal amino acids due to mutation of codon 1455 (which encodes serine) to a premature stop codon. Login to comment
86 In cells expressing GFP-CFTR-S1455X, the GFP mAb recognized 2 bands with relative molecular masses of approximately 210 and 240 kDa. Login to comment
113 Accordingly, we examined the cellular distribution of the COOH-terminal truncation mutant, S1455X, which lacks the COOH-terminal 26 amino acids including the PDZ-interacting domain (40). Login to comment
114 Patients with CFTR-S1455X have defective Cl-transport in sweat ducts (40). Login to comment
115 Examination of GFP-CFTR-S1455X localization by immunofluorescence confocal microscopy demonstrated that CFTR-S1455X was polarized to the lateral plasma 1356 The Journal of Clinical Investigation | November 1999 | Volume 104 | Number 10 Figure 1 The COOH-terminal PDZ-interacting domain (TRL) is required for polarization of CFTR to the apical membrane. Login to comment
130 GFP-CFTR-S1455X colocalized with the lateral membrane protein Na+-K+-ATPase (Figure 2d). Login to comment
131 Moreover, the ratio of GFP-CFTR-S1455X in the apical versus the basolateral plasma membrane was 0.2 ± 0.1 as determined by domain-selective cell-surface biotinylation (Table 1). Login to comment
133 That CFTR-S1455X was expressed primarily in the basolateral membrane, whereas CFTR-∆TRL was equally distributed in the apical and basolateral plasma membranes, suggests that some basolateral targeting information is suppressed or inactive in CFTR-∆TRL (see Discussion). Login to comment
136 To determine whether EPB50 interacts with and colocalizes with GFP-wt-CFTR in vivo, and whether the PDZ-interacting domain of CFTR is required for interaction and colocalization with EBP50, we coexpressed EBP50 with GFP-wt-CFTR, GFP-CFTR-∆TRL, or GFP-CFTR-S1455X in MDCK and COS cells. Examination of GFP-wt-CFTR and EBP50 by immunofluorescence confocal microscopy demonstrated that GFP-wt-CFTR and EBP50 colocalized to the apical plasma membrane of MDCK cells (Figure 3, a-c). Login to comment
139 By contrast, examination of GFP-CFTR-S1455X location by immunofluorescence confocal microscopy demonstrated that GFP-CFTR-S1455X did not colocalize with EBP50. Login to comment
140 GFP-CFTR-S1455X was polarized to the lateral plasma membrane, whereas EBP50 was polarized to the apical plasma membrane (Figure 3, g-i). Login to comment
141 To test the hypothesis that EBP50 and CFTR interact via the COOH-terminal PDZ-interacting domain of CFTR in vivo, we coexpressed EBP50 with GFP-wt-CFTR, GFP-CFTR-∆TRL, or GFP-CFTR-S1455X in COS cells and determined whether CFTR and EBP50 could be coimmunoprecipitated. Login to comment
142 EBP50 coimmunoprecipitated with GFP-wt-CFTR but not with GFP-CFTR-∆TRL (Figure 4) or GFP-S1455X. Login to comment
145 Discussion We have demonstrated that the last 3 amino acids in the COOH-terminus of CFTR (T-R-L) comprise a PDZ-interacting domain that is required for the polarization of CFTR to the apical plasma membrane in human airway and kidney epithelial cells. Our data also suggest that the polarization of CFTR to the apical plasma membrane involves interaction with an apical membrane PDZ The Journal of Clinical Investigation | November 1999 | Volume 104 | Number 10 1357 Table 1 Deletion of the PDZ-interacting domain of CFTR abrogates its apical polarization Cell line wt-CFTR CFTR-∆TRL CFTR-S1455X MDCK (Biotinylation) 7.5 ± 2.3 0.6A ± 0.3 0.2A ± 0.1 MDCK (Confocal) 3.0 ± 0.4 0.6A ± 0.1 0.1A ± 0.1 16HBE14o- (Confocal) 3.6 ± 0.6 0.7A ± 0.1 0.1A ± 0.1 Data are expressed as the ratio of CFTR expressed in the apical versus the basolateral plasma membrane. Login to comment
150 Figure 2 Confocal fluorescence micrographs (xz plane) of cells expressing GFP-wt-CFTR or GFP-CFTR-S1455X. Login to comment
153 (b) GFP-CFTR-S1455X is located in the lateral membrane of MDCK cells. Login to comment
154 (c) GFP-CFTR-S1455X is located in the lateral membrane of 16HBE14o-cells. Login to comment
155 (d) GFP-CFTR-S1455X (left panel in green) colocalizes with Na+-K+-ATPase (middle panel in red) in the lateral membrane (right panel is a merge of red and green channels, yellow-orange indicates colocalization). Login to comment
157 Note that some GFP-CFTR-S1455X is expressed in an intracellular compartment. Login to comment
180 Confocal fluorescence micrographs (xz plane) of MDCK cells coexpressing: (a-c) EBP50 and wt-CFTR, (d-e) EBP50 and CFTR-∆TRL, and (g-i) EBP50 and CFTR-S1455X. Login to comment
181 GFP-CFTR is green (a, d, g), EBP50 is red (b, e, h), and the merged red and green images are shown in c, f, and i. Colocalization of EBP50 and GFP-CFTR is orange-yellow in c and f. Note that some GFP-CFTR-S1455X and GFP-CFTR-∆TRL are expressed in an intracellular compartment (d and g). Login to comment
189 In the present study, we observed that approximately 30% of total cellular GFP-wt-CFTR was expressed in the plasma membrane, whereas only 1-3% of total cellular GFP-CFTR-∆TRL and GFP-S1455X was expressed in the plasma membrane. Login to comment
197 Although the polarization of CFTR-S1455X is dramatically different from wt-CFTR, this mutation does not cause CF, as pulmonary and pancreatic function appear to be normal; however, CFTR-S1455X results in elevated sweat chloride concentration (40). Login to comment
198 Because CFTR-S1455X is a functionally normal Cl-channel, we conclude that defective Cl-transport in sweat ducts is most likely due to the mispolarization of CFTR-S1455X to the lateral rather than the apical plasma membrane. Login to comment
199 We speculate that the relatively small fraction of CFTR-S1455X expressed at the apical membrane may be sufficient to sustain pulmonary and pancreatic function, but not sweat duct function. Login to comment
200 In addition, the fact that CFTR-S1455X was polarized to the lateral membrane, whereas CFTR-∆TRL was equally distributed between the apical and basolateral plasma membranes, suggests that some basolateral sorting information is suppressed in CFTR-∆TRL. Login to comment
202 Because sorting determinants are position dependent and hierarchical, deletion of the last 26 amino acids in CFTR may unmask the tyrosine and/or dileucine motifs, such that 1 or both of these motifs direct CFTR-S1455X to the lateral membrane (13, 14). Login to comment
216 Indeed, in MDCK cells stably expressing GFP-CFTR-∆TRL or GFP-CFTR-S1455X, we observed that CPT-cAMP-stimulated, transepithelial Cl-secretion was not different from parental, untransfected MDCK cells. Login to comment

PMID: 10773783 [PubMed] Zielenski J et al: "Genotype and phenotype in cystic fibrosis."

No. Sentence Comment

251 Sweat Ducts An interesting phenotype, presenting with elevated sweat Cl concentration in the absence of other CF symptoms, has been described in a patient with a nonsense mutation, S1455X. Login to comment
254 Detailed analyses of the S1455X CFTR variant have shown that the protein was normally processed and functional and therefore suggests that the truncated stretch of C-terminal amino acids plays some role in the sweat gland. Login to comment

PMID: 10852925 [PubMed] Moyer BD et al: "The PDZ-interacting domain of cystic fibrosis transmembrane conductance regulator is required for functional expression in the apical plasma membrane."

No. Sentence Comment

36 EXPERIMENTAL PROCEDURES Expression Vectors-pGFP-CFTR, pGFP-CFTR-⌬TRL, and pGFP-CFTR-S1455X, encoding enhanced GFP fused to the N terminus of wt-CFTR, CFTR lacking the 3 C-terminal amino acids, and CFTR lacking the 26 C-terminal amino acids, respectively, were constructed as described previously (23, 29). Login to comment
81 By contrast, EBP50 could not be co-immunoprecipitated with CFTR-QDTRA or CFTR-⌬TRL, which are nonpolarized, and, as shown previously, CFTR-S1455X (23) (Fig. 2 and Table I). Login to comment
82 CFTR-S1455X, a naturally occurring mutation that lacks the 26 C-terminal amino acids, is polarized to the lateral membrane (23). Login to comment
92 By contrast, in cells stably expressing mutant CFTRs that were not polarized to the apical plasma membrane, including CFTR-⌬TRL, CFTR-S1455X and CFTR-QDTRA, FIG. 1. Login to comment
104 CFTR AP/BL ratio Co-IP EBP50 Isc % ␮A/cm2 wt-CFTR 10.4 Ϯ 2.0 100 8.3 Ϯ 0.8 ⌬TRL 0.6 Ϯ 0.3a 0a 2.6 Ϯ 0.4a QDTRA 0.7 Ϯ 0.2a 0a 2.0 Ϯ 0.3a QDTAL 10.8 Ϯ 1.8 40a - QDARL 10.9 Ϯ 2.0 10a 3.6 Ϯ 0.6a QDVRL 11.2 Ϯ 1.9 16a 4.8 Ϯ 0.5a QATRL 15.2 Ϯ 2.0 74 8.6 Ϯ 0.9 ADTRL 11.4 Ϯ 2.0 78 7.6 Ϯ 1.5 S1455X 0.2 Ϯ 0.1a 0a 1.7 Ϯ 0.2a a Indicates cAMP-stimulated chloride secretion was not significantly different from parental, untransfected cells (Fig. 3). Login to comment
114 Similar inefficient expression was observed for CFTR-S1455X, CFTR-QDTRA, CFTR-QDVRL and CFTR-QDARL (2-5% of total CFTR was expressed in the plasma membranes). Login to comment
129 By contrast, CFTR proteins that did not associate with EBP50, including QDTRA (* indicates protein could not be detected) and, as shown previously, S1455X and ⌬TRL (23), were not polarized to the apical membrane (Fig. 1). Login to comment
141 By contrast, CFTR mutants that were not polarized to the apical membrane, including ⌬TRL, S1455X, and QDTRA, did not produce cAMP-stimulated chloride currents significantly different from cAMP-stimulated currents in untransfected, parental cells. Login to comment
144 Number of monolayers studied was: 14 for parental cells, 22 for wt-CFTR, 14 for ⌬TRL, 8 for S1455X, 21 for QDTRA, 14 for QDVRL, 17 for QDARL, 5 for QATRL, and 4 for ADTRL. Login to comment

PMID: 10893422 [PubMed] Sun F et al: "E3KARP mediates the association of ezrin and protein kinase A with the cystic fibrosis transmembrane conductance regulator in airway cells."

No. Sentence Comment

301 Support for this concept is provided by the naturally occurring CFTR mutation, S1455X, which deletes part of the CFTR COOH terminus (33). Login to comment

PMID: 11022033 [PubMed] Gentzsch M et al: "Localization of sequences within the C-terminal domain of the cystic fibrosis transmembrane conductance regulator which impact maturation and stability."

No. Sentence Comment

235 Another truncation detected in a family where the sweat gland may be the sole tissue effected, S1455X (42), would not influence the turnover of either form of CFTR. Login to comment

PMID: 11101688 [PubMed] Jezequel P et al: "Molecular screening of the CFTR gene in men with anomalies of the vas deferens: identification of three novel mutations."

No. Sentence Comment

74 Other authors (Mickle et al., 1998; Moyer et al., 1999) One mutation detected and one T5 allele (15/47 ϭ 31.9%) have demonstrated that a nonsense S1455X mutation in exon 1 ∆F508/- (TG)10T9/(TG)12T5 24 encoded a truncated version of the CFTR protein which 3 ∆F508/- (TG)10T9/(TG)12T5 missed the last 26 amino acids and mispolarized to the lateral5 ∆F508/- (TG)10T9/(TG)12T5 6 ∆F508/- (TG)10T9/(TG)12T5 membrane of epithelia. Login to comment
75 The child and mother bearing the 10 ∆F508/- (TG)10T9/(TG)12T5 del14a/S1455X genotype were clinically well but had consist-13 ∆F508/- (TG)10T9/(TG)13T5 ently elevated sweat chloride concentrations (74 mmol/l). Login to comment

PMID: 11158459 [PubMed] Wine JJ et al: "Comprehensive mutation screening in a cystic fibrosis center."

No. Sentence Comment

86 Mutations in the Stanford CF Mutation Database After Screening With the Genzyme70 Assay Mutation n % n % ⌬F508 353 67.11% 353 67.11% Splice mutations 16 3.04% 621ϩ1 G3T 5 0.95% 1717-1 G3A 5 0.95% 2789ϩ5 G3A 1 0.19% 1898ϩ1 G3A 1 0.19% 3849ϩ10 kb C3T 4 0.76% Stop mutations 31 5.89% Q493X 1 0.19% G542X 13 2.47% R553X 4 0.76% R1162X 1 0.19% W1282X 10 1.90% S1455X 2 0.38% Insertions/deletions 9 1.71% 681 del C 1 0.19% 2184 del A 2 0.38% 3859 del C 5 0.95% 3905 ins T 1 0.19% Missense mutations 33 6.27% G85E 4 0.76% R117H 3 0.57% R334W 6 1.14% G551D 14 2.66% R560T 3 0.57% N1303K 3 0.57% Unknown mutations 84 15.97% 84 15.97% Total 526 100.00% 526 100.00% ARTICLES tients with positive sweat tests were selected for SSCP/HA analysis based on clinical status, ethnicity, and previous screening with the Genzyme70 assay. Login to comment

PMID: 11171377 [PubMed] Milewski MI et al: "A PDZ-binding motif is essential but not sufficient to localize the C terminus of CFTR to the apical membrane."

No. Sentence Comment

114 This truncation corresponds to the naturally occurring CFTR mutation S1455X that was associated with sweat gland dysfunction (Mickle et al., 1998). Login to comment
144 (a) Loss of apical localization of GFP-CFTR 1370-1480 ∆ag construct (green) after truncation of last 26 amino acids (S1455X), truncation of last three amino acids (∆TRL), or substitution of last three amino acids with alanines (TRL→AAA). Login to comment

PMID: 11278980 [PubMed] Ahn W et al: "Regulatory interaction between the cystic fibrosis transmembrane conductance regulator and HCO3- salvage mechanisms in model systems and the mouse pancreatic duct."

No. Sentence Comment

60 Site-directed Mutagenesis-Oligonucleotide-directed mutagenesis using the GeneEditor mutagenesis kit (Promega, Madison, WI) was performed in the CFTR expression vector pCMVNot6.2 to delete the C-terminal 4 (⌬DTRL) or 26 (S1455X) amino acids. Login to comment
63 The mutagenesis primers were as follows: ⌬DTRL, 5Ј-GGA GAC AGA AGA AGA GGT GTA AGA TAC AAG GCT TTA GAG AG-3Ј; S1455X, 5Ј-GCT CTT TCC CCA CCG GAA CTG AAG CAA GTG CAA GTC TAA GCC-3Ј. Login to comment
174 Another finding of note in Fig. 5 is the behavior of a mutant CFTR protein lacking the final C-terminal 26 amino acids (S1455X). Login to comment
176 Similar to the findings with the CFTR-⌬DTRL, the CFTR-S1455X did not associate with NHE3 (Fig. 5B) and had no effect on NHE3 activity (Fig. 5C). Login to comment
208 PS120/NHE3 cells were transfected with mammalian expressing vectors for WT-CFTR, CFTR-⌬DTRL, and CFTR-S1455X. Login to comment

PMID: 11504857 [PubMed] Chen JM et al: "A combined analysis of the cystic fibrosis transmembrane conductance regulator: implications for structure and disease models."

No. Sentence Comment

542 Indeed, neither S1455X (Mickle et al. 1998) nor Q1476X (http:// www.genet.sickkids.on.ca/cftr) caused a severe CF phenotype. Login to comment

PMID: 12084728 [PubMed] Milewski MI et al: "Aggregation of misfolded proteins can be a selective process dependent upon peptide composition."

No. Sentence Comment

125 To examine whether this C-terminal region contributed to the unusual accumulation pattern of HA-CFTR 1370-1480, we deleted the last 26 amino acids in this construct by introducing the naturally occurring CFTR mutation S1455X (33), associated with abnormal localization of the full-length protein (31). Login to comment

PMID: 12578973 [PubMed] Ostedgaard LS et al: "Effects of C-terminal deletions on cystic fibrosis transmembrane conductance regulator function in cystic fibrosis airway epithelia."

No. Sentence Comment

7 Deletion of 26 C-terminal residues by the S1455X mutation was associated with elevated sweat Cl- concentrations, but not other manifestations of CF (4), whereas deletion of the last 70 residues by the Q1412X mutation caused CF (C. J. Taylor, personal communication). Login to comment
117 In addition, whole-cell patch-clamp studies of BHK-21 and IB3-1 cells reported that the S1455X mutation had no effect on current, but the Q1412X mutation reduced current by 90% (4, 19). Login to comment
184 These findings are consistent with previous reports that maturation and degradation of C-terminally truncated CFTR (S1455X and D1425X) is similar to WT in COS and BHK cells (19-21). Login to comment
248 The S1455X was associated with an elevated sweat Cl-concentration, but not airway or pancreatic disease (4), and the 1476X deletion was found in a person with congenital bilateral absence of the vas deferens (personal communication, M. Claustres, Montpellier, France). Login to comment

PMID: 12651858 [PubMed] Benharouga M et al: "The role of the C terminus and Na+/H+ exchanger regulatory factor in the functional expression of cystic fibrosis transmembrane conductance regulator in nonpolarized cells and epithelia."

No. Sentence Comment

2 Individuals with mutations resulting in premature termination of CFTR (S1455X or ⌬26 CFTR) have moderately elevated sweat Cl-concentration, without an obvious lung and pancreatic phenotype, implying that the CFTR function is largely preserved. Login to comment

PMID: 12919146 [PubMed] Bienvenu T et al: "Mutations located in exon 24 of the CFTR gene are associated with a mild cystic fibrosis phenotype."

No. Sentence Comment

3 However, Mickle et al. described a nonsense mutation, S1455X, located in exon 24, which was associated with elevated sweat chloride concentrations in the absence of the CF phenotype in female compound heterozygotes (2). Login to comment

PMID: 14662004 [PubMed] Zeitlin PL et al: "Emerging drug treatments for cystic fibrosis."

No. Sentence Comment

88 Class of mutation Molecular mechanism Pancreatic status (if known) Examples 1 No CFTR protein synthesis PI W1282X, G542X, R553X, 621 + 1 G→T, 1717-1 G→A, 3905insT, 394delTT 2 Abnormal CFTR processing and trafficking PI ∆F508, N1303K, P574H 3 Defective CFTR regulation (normal trafficking) PI G551D, G551S, G1349D, S1255P 4 Decreased CFTR chloride conductance PS R117H, R334W, R347P, P547H 5 Reduced synthesis and trafficking of normal CFTR PS A455E, 3849 + 10kb C→T, (5T) 6A Reduced apical stability PI S1455X, Q1412S, 4326delTC, 4279insA 6B Defective regulation of other ion channels PI G551D Note that the G551D is placed in Class 3 for defective regulation and Class 6B for defective regulation of the outwardly rectifying chloride channel. Login to comment

PMID: 15666307 [PubMed] Salvatore D et al: "Isolated elevated sweat chloride concentrations in the presence of the rare mutation S1455X: an extremely mild form of CFTR dysfunction."

No. Sentence Comment

0 American Journal of Medical Genetics 133A:-208 (2005) Clinical Report Isolated Elevated Sweat Chloride Concentrations in the Presence of the Rare Mutation S1455X: An Extremely Mild Form of CFTR Dysfunction Donatello Salvatore,1 * Rossella Tomaiuolo,2 Borghina Vanacore,2 Ausilia Elce,2 Giuseppe Castaldo,2,3 and Francesco Salvatore2 1 Pediatric Division, Cystic Fibrosis Center, San Carlo Hospital, Potenza, Italy 2 CEINGE-Advanced Biotechnologies and Department of Biochemistry and Medical Biotechnologies, University of Naples ''Federico II``, Naples, Italy 3 Faculty of Sciences, University of Molise, Isernia, Italy Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) have been shown to cause typical cystic fibrosis (CF) and several milder phenotypes. Login to comment
1 We report on two asymptomatic sisters who had isolated increased sweat chloride concentrations, and in whom systematic scanning of the whole coding region of the CFTR generevealedtheF508del/S1455X genotype. Login to comment
9 Mickle et al. [1998] described a mother and a daughter who had isolated elevated sweat chloride concentrations, and the non-sense mutation S1455X in compound heterozygosis with the del14a deletion [Mickle et al., 1998]. Login to comment
10 We report on two asymptomatic sisters who had increased sweat chloride concentrations, and in whom systematic scanning of the whole coding region of the CFTR gene revealed the F508del/S1455X genotype. Login to comment
27 The analysis revealed the non-sense mutation S1455X, in compound heterozygosity with F508del. Login to comment
35 E-mail: saverdon@tiscali.it Received 31 March 2004; Accepted 21 October 2004 DOI 10.1002/ajmg.a.30518 ß 2005 Wiley-Liss, Inc. and gene scanning confirmed the presence of the F508del/ S1455X genotype (Table I). Login to comment
37 The analysis revealed the presence of the mutation F508del in heterozygosis in the mother and of the mutation S1455X in heterozygosis in the father. Login to comment
38 DISCUSSION Our case report confirms that S1455X is a rare mutation associated with isolated elevated sweat chloride concentrations in the absence of the CF phenotype. Login to comment
39 Although, we cannot exclude changes in the patients` clinical conditions in the future, the long follow-up (8 years) of these two sisters and the normal clinical picture of the previously reported patients, indicate that S1455X is related to the isolated sweat gland dysfunction [Moyer et al., 1999]. Login to comment
40 The possible explanation of this phenotype is that the CFTR mRNA transcript bearing the S1455X mutation is stable, and encodes a version of CFTR that lacks the last 26 amino acids, which is processed to a mature state and functions similarly to wild-type CFTR [Mickle et al., 1998]. Login to comment
41 In addition, the S1455X CFTR mutation is mispolarized to the lateral membrane of epithelial cells [Moyer et al., 1999]. Login to comment
42 The transport of the electrolytes across the respiratory epithelia should be studied in vivo by means of measurement of nasal potential difference (NPD) in patients carrying the S1455X mutation, in order to evaluate the organ specific expression of the mutated gene, the hypothesis being that sodium and chloride transport might be normal or near normal at the level of airway epithelial cells despite the abnormal sweat electrolytes. Login to comment
45 The most distal CF-associated mutation reported is a missense mutation predicted to replace aspartic acid for asparagine at amino acid 1445 [Cystic Fibrosis Genetic Analysis Consortium, 2004], whereas mutations more distal with respect to S1455X have been associated to the congenital bilateral absence of vasa deferentes. Login to comment
46 All compound heterozygotes with the S1455X mutation so far reported are female, so we cannot exclude the possibility that this mutation in males would be related to isolated elevated sweat chloride and infertility. Login to comment
47 The fact that a very mild phenotype is associated with S1455X is important for genetic counseling. Login to comment
49 In the case of our adult patient, we calculated the risk of having a CF child of 1:334, but the risk could be further ''halved`` based on the hypothesis that a S1455X compound heterozygote would be asymptomatic. Login to comment

PMID: 16085675 [PubMed] Farmen SL et al: "Gene transfer of CFTR to airway epithelia: low levels of expression are sufficient to correct Cl- transport and overexpression can generate basolateral CFTR."

No. Sentence Comment

275 Third, evidence that mislocalization of CFTR might have a physiological consequence comes from the study of the S1455X mutation, which was located in the basolateral membrane in airway epithelial cells (27). Login to comment
272 Third, evidence that mislocalization of CFTR might have a physiological consequence comes from the study of the S1455X mutation, which was located in the basolateral membrane in airway epithelial cells (27). Login to comment

PMID: 16113408 [PubMed] Guggino WB et al: "The cystic fibrosis transmembrane regulator forms macromolecular complexes with PDZ domain scaffold proteins."

No. Sentence Comment

130 Several years ago, our group reported the identification of a 6.8-kb deletion (del14a) and a nonsense mutation (S1455X) in the CFTR genes of a mother and her youngest daughter with isolated elevated sweat chloride concentrations but with no evidence of pulmonary or pancreatic disease characteristic of cystic fibrosis. Login to comment
131 Further study showed that the S1455X-CFTR mutant generated cAMP-activated whole-cell chloride currents similar to wild-type CFTR. These data are consistent with the relatively normal lung and pancreatic function observed in the mother and her daughter (32). Login to comment
135 When the S1455X mutant is expressed in polarized, heterologous epithelial cells, a significant portion accumulates at the lateral membrane. Login to comment
146 There are limited data on a small number of individuals with the S1455X mutation, which makes it difficult to generalize on the role of the C terminus in CFTR biology. Login to comment

PMID: 16124861 [PubMed] Cutting GR et al: "Modifier genetics: cystic fibrosis."

No. Sentence Comment

193 This point may be best illustrated by the identification of four individuals in two unrelated families who carry a severe CF mutation paired with a rare nonsense mutation in CFTR (S1455X). Login to comment
557 Isolated elevated sweat chloride concentrations in the presence of the rare mutation S1455X: an extremely mild form of CFTR dysfunction. Login to comment

PMID: 16281647 [PubMed] Southern KW et al: "Establishing a diagnosis of cystic fibrosis."

No. Sentence Comment

54 One mutation of the CFTR gene (S1455X) results in an abnormal sweat test but no other phenotypic evidence of CF.10 This is a nonsense mutation that results in a truncated CFTR protein with the final 26 amino acids missing. Login to comment

PMID: 16283887 [PubMed] Epaud R et al: "Mild cystic fibrosis revealed by persistent hyponatremia during the French 2003 heat wave, associated with the S1455X C-terminus CFTR mutation."

No. Sentence Comment

0 Letter to the Editor Mild cystic fibrosis revealed by persistent hyponatremia during the French 2003 heat wave, associated with the S1455X C-terminus CFTR mutation To the Editor: Cystic fibrosis (CF) - an autosomal recessive disorder with widely variable presentation - is caused by a dysfunction of the CF transmembrane conductance regulator (CFTR) protein. Login to comment
13 The patient was a compound heterozygote for the F508del (maternally inherited) and the S1455X mutation located in the last exon 24 (paternally inherited). Login to comment
17 The S1455X mutation, encoding a truncated CFTR protein missing the last 26 amino acids, was originally described in the sib and the mother of a CF patient, who were compound heterozygotes for the S1455X mutation and a genomic 8.6 kb deletion removing exon 14a (3). Login to comment
19 A recent report documented two sisters with the [F508del] þ [S1455X] genotype and elevated sweat chloride values. Login to comment
21 Functional studies failed to elucidate the association of S1455X with elevated sweat chloride values (5-8). Login to comment
25 All rights reserved CLINICAL GENETICS doi: 10.1111/j.1399-0004.2005.00525.x 552 vas deferens (CBAVD) (4428insAG), apparently isolated CBAVD (E1473X and E1476X), and isolated positive sweat test (S1455X) (3, 4). Login to comment
26 Contrary to the previous S1455X-associated cases, our compound heterozygous [F508del] þ [S1455X] patient is a boy, and CBAVD-associated infertility may possibly occur. Login to comment
28 S1455X might not have a specific effect on CFTR function, but belong to a group of mild C-terminus CFTR truncation mutations. Login to comment
42 Isolated elevated sweat chloride concentrations in the presence of the rare mutation S1455X: an extremely mild form of CFTR dysfunction. Login to comment

PMID: 16648884 [PubMed] Mishra A et al: "The relevance of sweat testing for the diagnosis of cystic fibrosis in the genomic era."

No. Sentence Comment

244 Highsmith and colleagues (1994) studied 23 patients with pulmonary disease characteristic of CF but with a normal sweat test and identified a point mutation in intron 19 of the CFTR gene, termed 3849+10kb C-T.15 This mutation produces an alternative splicing site and decreased amounts of CFTR mRNA can be detected.16 Thus, according to the classification of the CFTR mutations, this mutation falls into Class V.16,67 Other mutations associated with normal or borderline sweat electrolytes are R117H, D1152H, A455E, G551S and 2789+5G - A.9,24,78 An interesting phenotype, presenting with elevated sweat chloride concentration in the absence of other CF symptoms, has been described in a patient with a nonsense mutation, S1455X.105 This mutation truncates 26 amino acids from the C-terminus of the protein product. Login to comment
246 CFTR mRNA transcripts bearing the S1455X mutation were normally processed and functional, which therefore suggests that the truncated stretch C-terminal amino acid plays some role in the sweat gland only. Login to comment

PMID: 17534127 [PubMed] Southern KW et al: "Cystic fibrosis and formes frustes of CFTR-related disease."

No. Sentence Comment

175 In contrast, a nonsense mutation (S1455X) results in truncation of the final 26 amino acids in CFTR and people with this mutation have a positive sweat test with raised sweat chloride levels, but no evidence of lung disease [107]. Login to comment

PMID: 17541014 [PubMed] Rowe SM et al: "Restoration of W1282X CFTR activity by enhanced expression."

No. Sentence Comment

208 Supporting this hypothesis, Mickle and coworkers reported that a disease-causing CFTR mutation produced by a PTC located 26 amino acids from the C-terminus (S1455X CFTR) retains partial function and demonstrates a mild pulmonary phenotype (but abnormal ion transport in the sweat gland [42]). Login to comment

PMID: 18493878 [PubMed] Paranjape SM et al: "Atypical cystic fibrosis and CFTR-related diseases."

No. Sentence Comment

64 Determination of the transepithelial nasal potential difference has been beneficial in establishing a CF Table 1 Mutations, sites, and molecular consequences associated with either an atypical presentation of CF respiratory disease or pancreatic sufficiency or late-onset pancreatic insufficiency (http:// www.genet.sickkids.on.ca) Mutation Site Consequence Atypical presentation M1210I Exon 19 Met to Ile at 1210 S1455X Exon 24 Ser to Stop at 1455 1811+18G→A Intron 11 mRNA splicing defect L346P Exon 7 Leu to Pro at 346 Y161D Exon 4 Tyr to Asp at 161 R31C Exon 2 Arg to Cys at 31 I752S Exon 13 Ile to Ser at 752 2811G/T Exon 15 Sequence variation Pancreatic sufficiency or late-onset pancreatic insufficiency R600G Exon 13 Arg to Gly at 600 D1152H Exon 18 Asp to His at 1152 Y89C Exon 3 Tyr to Cys at 89 R117H Exon 4 Arg to His at 117 D110E Exon 4 Asp to Glu at 110 296 + 3insT Intron 2 mRNA splicing defect E217G Exon 6a Glu to Gly at 217 V392G Exon 8 Val to Gly at 392 N1088D Exon 17b Asn to Asp at 1088 S737F Exon 13 Missense 1716+1G→A Intron 10 mRNA splicing defect R334W Exon 7 Arg to Trp at 334 R347P Exon 7 Arg to Pro at 347 A455E Exon 9 Ala to Glu at 455 P574H Exon 12 Pro to His at 574 3850-3T→G Intron 19 mRNA splicing defect diagnosis in many atypical cases. Login to comment

PMID: 9671706 [PubMed] Hall RA et al: "A C-terminal motif found in the beta2-adrenergic receptor, P2Y1 receptor and cystic fibrosis transmembrane conductance regulator determines binding to the Na+/H+ exchanger regulatory factor family of PDZ proteins."

No. Sentence Comment

149 Interestingly, a naturally occurring truncation of the tail of CFTR (S1455X) has been recently reported (24). Login to comment

PMID: 11826280 [PubMed] Russel FG et al: "Molecular aspects of renal anionic drug transport."

No. Sentence Comment

224 The CFTR mutant S1455X, which lacks the26C-terminalaminoacids,nolongerbindstoNHERF-1andismislocatedtothe lateral membrane upon expression in kidney (MDCK) and airway (16HBE14o-) epithelial cells (125). Login to comment
254 The CFTR mutant S1455X, which lacks the26C-terminalaminoacids,nolongerbindstoNHERF-1andismislocatedtothe lateral membrane upon expression in kidney (MDCK) and airway (16HBE14o-) epithelial cells (125). Login to comment

PMID: 23045527 [PubMed] Duan Y et al: "Keratin K18 increases CFTR surface expression by binding to its C-terminal hydrophobic patch."

No. Sentence Comment

23 Interestingly, clinical studies suggest that the deletion of CFTR`s C-terminal 26 residues by the S1455X mutation elevates the chloride concentration in sweat without producing any other CF symptoms, while the deletion of the C-terminal 69 residues by Q1412X mutation results in severe CF (8-10). Login to comment
238 It is possible that mutation Q1412X in CFTR, but not mutation S1455X, disrupts the K18 binding site and thus leads to the loss of plasmalemmal CFTR in epithelia and causes severe CF in patients. Login to comment
17 Interestingly, clinical studies suggest that the deletion of the CFTR C-terminal 26 residues by the S1455X mutation elevates the chloride concentration in sweat without producing any other CF symptoms, whereas the deletion of the C-terminal 69 residues by the Q1412X mutation results in severe CF (8-10). Login to comment
291 It is possible that mutation Q1412X in CFTR, but not mutation S1455X, disrupts the K18-binding site and thus leads to the loss of plasmalemmal CFTR in epithelia and causes severe CF in patients. Login to comment

PMID: 17662673 [PubMed] Alibakhshi R et al: "Analysis of the CFTR gene in Iranian cystic fibrosis patients: identification of eight novel mutations."

No. Sentence Comment

38 1 p.N1303K E21 C to G at 4041 Asn to Lys at 1303 6 p.S1455X E24 C to G at 4496 Ser to stop at 1455 1 c.186-?_296+?del E2 Large in frame deletion starting in intron 1, ending in intron 2 1 c.1342-?_1524+?del E9 Large in frame deletion starting in intron 8, ending in intron 9 1 c.406-?_1716+?del E4-E10 Large in frame deletion starting in intron 3, ending in intron 10 2 Mutations described for the first time appear in bold. Login to comment
66 Results A total of 69 unrelated CF patients (38 male and 31 female; aged between 2 months and 15 years) of Iranian Table 2 Genotype of CFTR genes in 53 Iranian patients Genotype Exon/intron Number of patients p.F508del/p.F508del E10/E10 10 p.F508del/p.R1162X E10/E19 2 p.F508del/p.T1036I E10/E17a 1 p.F508del/p.R1066C E10/E17b 1 p.F508del/c.1342-?_1524+?del E10/E9 1 p.S466X/p.S466X E10/E10 4 c.2183_2184delAAinsG/ c.2183_2184delAAinsG E13/E13 4 c.2183_2184delAAinsG/c.186- ?_296+?del E13/E2 1 p.N1303K/p.N1303K E21/E21 2 p.N1303K/p.S945L E21/E15 1 p.N1303K/c.1677delTA E21/E10 1 p.G542X/p.G542X E11/E11 2 p.G542X/c.2789+5GNA E11/I14b 1 c.3120+1GNA/c.3120+1GNA I16/I16 2 c.3120+1GNA/c.3121-1GNA I16 1 c.3121-1GNA/p.T1086I I16/E17b 1 c.3130delA/c.3130delA E17a/E17a 2 p.D192G/p.D192G E5/E5 1 p.R334W/p.R334W E7/E7 1 p.R334W/p.S945L E7/E15 1 p.R334W/p.L1077P E7/E17b 1 c.1525-1GNA/c.1525-1GNA I9/I9 1 p.S549R/p.S549R E11/E11 1 p.A566D/p.A566D E12/E12 1 c.1898+1GNT/c.1898+1GNT I12/I12 1 c.2576delA/p.S1455X/ E13/E24 1 c.2184insA/c.1677delTA E10/E13 1 p.R785X/p.R785X E13/E13 1 c.2752-1_2756delGGTGGCinsTTG/ c.2752-1_2756delGGTGGCinsTTG I14a/E14b 1 c.2789+5GNA/c.2789+5GNA I14b/I14b 1 p.K1177X/p.K1177X E19/E19 1 c.406-?_1716+?del/c.406-?_1716+?del E4-E10/E4-E10 1 Total 53 origin were extensively studied for the presence of mutations in the CFTR gene, for the presence of the deep intronic 3849+10 kbC→T mutation, and large deletions/ duplications. Login to comment
96 It was found once in a patient that carried S1455X in compound heterozygosity. Login to comment
65 Results A total of 69 unrelated CF patients (38 male and 31 female; aged between 2 months and 15 years) of Iranian Table 2 Genotype of CFTR genes in 53 Iranian patients Genotype Exon/intron Number of patients p.F508del/p.F508del E10/E10 10 p.F508del/p.R1162X E10/E19 2 p.F508del/p.T1036I E10/E17a 1 p.F508del/p.R1066C E10/E17b 1 p.F508del/c.1342-?_1524+?del E10/E9 1 p.S466X/p.S466X E10/E10 4 c.2183_2184delAAinsG/ c.2183_2184delAAinsG E13/E13 4 c.2183_2184delAAinsG/c.186- ?_296+?del E13/E2 1 p.N1303K/p.N1303K E21/E21 2 p.N1303K/p.S945L E21/E15 1 p.N1303K/c.1677delTA E21/E10 1 p.G542X/p.G542X E11/E11 2 p.G542X/c.2789+5GNA E11/I14b 1 c.3120+1GNA/c.3120+1GNA I16/I16 2 c.3120+1GNA/c.3121-1GNA I16 1 c.3121-1GNA/p.T1086I I16/E17b 1 c.3130delA/c.3130delA E17a/E17a 2 p.D192G/p.D192G E5/E5 1 p.R334W/p.R334W E7/E7 1 p.R334W/p.S945L E7/E15 1 p.R334W/p.L1077P E7/E17b 1 c.1525-1GNA/c.1525-1GNA I9/I9 1 p.S549R/p.S549R E11/E11 1 p.A566D/p.A566D E12/E12 1 c.1898+1GNT/c.1898+1GNT I12/I12 1 c.2576delA/p.S1455X/ E13/E24 1 c.2184insA/c.1677delTA E10/E13 1 p.R785X/p.R785X E13/E13 1 c.2752-1_2756delGGTGGCinsTTG/ c.2752-1_2756delGGTGGCinsTTG I14a/E14b 1 c.2789+5GNA/c.2789+5GNA I14b/I14b 1 p.K1177X/p.K1177X E19/E19 1 c.406-?_1716+?del/c.406-?_1716+?del E4-E10/E4-E10 1 Total 53 origin were extensively studied for the presence of mutations in the CFTR gene, for the presence of the deep intronic 3849+10 kbC࢐T mutation, and large deletions/ duplications. Login to comment
95 It was found once in a patient that carried S1455X in compound heterozygosity. Login to comment

PMID: 15463893 [PubMed] Braunstein GM et al: "Purinergic signaling underlies CFTR control of human airway epithelial cell volume."

No. Sentence Comment

6 In contrast, parental IB3-1 CF cells or IB3-1 cells expressing CFTR mutants (DF508, G551D, and S1455X) failed to RVD. Login to comment
119 IB3-1 cells express the DF508-CFTR and W1282X-CFTR mutations endogenously [35,49]. Login to comment
121 No CFTR protein was detectable in ''mock controls``, while band B ''core glycosylated`` (130-140 kDa) and band C ''maturely glycosylated`` (160-180 kDa) forms of CFTR were found for WT-CFTR, T1478X (also DTRL)-CFTR, S1455X-CFTR, and G551D-CFTR [9,51,52]. Login to comment
122 S1455X-CFTR showed a similar profile to T1478X-CFTR (data not shown). Login to comment
163 In similar experiments, DF508-CFTR and G551D-CFTR required at least 40 min to return to this threshold, and S1455X-CFTR required 30 min (data not shown). Login to comment
185 Cells expressing the more severe mutations, DF508-CFTR and G551D-CFTR, or the more severe C-terminal truncation mutant, S1455X-CFTR, were unable to fully recover their cell volume after hypotonic cell swelling. Login to comment
205 However, the cells transiently transfected with DF508-CFTR, G551D-CFTR, and S1455X-CFTR did not show a response (Fig. 5B). Login to comment
118 No CFTR protein was detectable in ''mock controls``, while band B ''core glycosylated`` (130-140 kDa) and band C ''maturely glycosylated`` (160-180 kDa) forms of CFTR were found for WT-CFTR, T1478X (also DTRL)-CFTR, S1455X-CFTR, and G551D-CFTR [9,51,52]. Login to comment
158 In similar experiments, DF508-CFTR and G551D-CFTR required at least 40 min to return to this threshold, and S1455X-CFTR required 30 min (data not shown). Login to comment
180 Cells expressing the more severe mutations, DF508-CFTR and G551D-CFTR, or the more severe C-terminal truncation mutant, S1455X-CFTR, were unable to fully recover their cell volume after hypotonic cell swelling. Login to comment
200 However, the cells transiently transfected with DF508-CFTR, G551D-CFTR, and S1455X-CFTR did not show a response (Fig. 5B). Login to comment

PMID: 9674722 [PubMed] Schwiebert EM et al: "Cystic fibrosis: a multiple exocrinopathy caused by dysfunctions in a multifunctional transport protein."

No. Sentence Comment

299 Examples of such nonsense mutations are G542X in NBF1, W1282X in NBF2, and S1455X in the C-terminus of the CFTR protein. Login to comment

PMID: 9499426 [PubMed] Mickle JE et al: "A mutation in the cystic fibrosis transmembrane conductance regulator gene associated with elevated sweat chloride concentrations in the absence of cystic fibrosis."

No. Sentence Comment

1 We report the identification of a 6.8 kb deletion (del14a) and a nonsense mutation (S1455X) in the CFTR genes of a mother and her youngest daughter with isolated elevated sweat chloride concentrations. Login to comment
4 CFTR mRNA transcripts bearing the S1455X mutation were stable in vivo, implying that this allele encoded a truncated version of CFTR missing the last 26 amino acids. Login to comment
5 Loss of this region did not affect processing of transiently expressed S1455X-CFTR compared with wild-type CFTR. Login to comment
7 Preservation of chloride channel function of S1455X-CFTR was consistent with normal lung and pancreatic function in the mother and her daughter. Login to comment
28 Shading indicates CFTR alleles: del14a alleles are solid, S1455X alleles are hatched and the wild-type allele is unshaded. Login to comment
54 Identification of nonsense mutation S1455X in mother and daughter with elevated sweat chloride concentrations Screening for 16 CF mutations common among Caucasians by reverse dot-blot assay did not detect a mutation in any family member. Login to comment
71 This novel mutation is predicted to change the codon for serine at residue 1455 to an opal termination codon, and is designated S1455X.Both theproband`s mother and sister are compound heterozygotes for deletion 14a and S1455X (Fig. 1). Login to comment
73 Since the del14a mutation caused the CF phenotype in the homozygous state, we predicted that the S1455X mutation was the cause of the isolated elevated sweat chloride concentrations in the sister and mother. Login to comment
74 CFTR mRNA transcript bearing the S1455X mutation is stable RT-PCR was used to determine the consequences of the del14a and S1455X mutations upon transcript splicing and stability. Login to comment
78 Since nonsense mutations frequently cause severe reduction in mRNA levels (28), the stability of mRNA transcripts bearing the nonsense mutation S1455X was assessed as follows. Login to comment
81 Immunoprecipitation of wild-type and S1455X CFTR transiently expressed in HEK 293 cells. Login to comment
82 Wild-type CFTR and S1455X CFTR proteins immunoprecipitated with the R-domain-specific monoclonal antibody are indicated by the arrow.Both migrateat ~175kDa.TheS1455XCFTRtruncated protein was not detected by immunoprecipitation with the C-terminus-specific antibody. Login to comment
85 the larger amplicon carrying the S1455X mutation was at similar levels to the smaller amplicon missing exon 14a (Fig. 3). Login to comment
86 Thus, normal CFTR mRNA transcripts and transcripts either bearing S1455X or missing exon 14a were present at similar levels, indicating that the S1455X transcripts were stable. Login to comment
87 To verify this result, we compared the levels of CFTR transcripts bearing S1455X with those missing exon 14a by RT-PCR amplification of exon 24 followed by hybridization with oligonucleotides specific for each transcript. Login to comment
89 Quantitation of the hybridization signals by phosphoimaging indicated that S1455X CFTR transcripts were stable, although less abundant (37.9 ± 1.99% SEM, n = 7) than del14a CFTR (62.1 ± 1.17% SEM). Login to comment
90 Since the S1455X CFTR mRNA was stable, we predicted that CFTR missing the last 26 amino acids was produced in vivo. Login to comment
91 The S1455X CFTR truncated protein is processed to a mature state and functions similarly to wild-type CFTR Processing of CFTR bearing S1455X was evaluated by immunoprecipitation using commercially available monoclonal antibodies directed against the R-domain or the last four residues at the C-terminus (Genzyme). Login to comment
93 Both S1455X CFTR and wild-type CFTR products immunoprecipitated with the R-domain antibody have an apparent Mr of 175 kDa (Fig. 4). Login to comment
94 As expected, the S1455X CFTR mutant truncated at the C-terminus was not immunoprecipitated by the C-terminus antibody (Fig. 4). Login to comment
96 Since the S1455X mutant appears to undergo post-translational modifications similar to wild-type CFTR, we expected that the mutant protein would be properly folded and inserted into the cell membrane. Login to comment
97 To assay function, wild-type and S1455X CFTRcDNAs were transiently transfected into CF airway epithelial cells (IB3-1) devoid of functional CFTR. Login to comment
99 Whole-cell chloride current activated by cAMP in IB3-1 cells transfected with wild-type CFTR or S1455X CFTR.Current-voltage plots for wild-type CFTR (left) and S1455X CFTR (right) in the presence of CPT-cAMP (200 µM) are shown as filled symbols. Login to comment
103 Incubation with a non-hydrolyzable form of cAMP (CPT-cAMP; 200 µM) evoked chloride currents of similar magnitude in wild-type CFTR (+100 mV: 1090.9 ± 84.2 SEM pA; n = 12) and S1455X CFTR (+100 mV: 938.9± 114.4 pA; n = 20) transfected cells that were significantly higher (P < 0.05) than non-transfected cells (+100 mV: 89.3 ± 34.0 pA; n = 5). Login to comment
106 Whole-cell patch-clamp analysis of IB3-1 cells transfected with S1455X CFTR displayed cAMP-activated currents that were outwardly rectified and inhibited by glybenclamide (+100 mV: 302.7 ± 127.5 pA; n = 7). Login to comment
107 Thus, S1455X CFTR generates robust cAMP-activated chloride currents similarly to wild-type CFTR. Login to comment
119 The good health of the mother at 46 years of age suggested a very low likelihood that the S1455X/ del14a genotype causes CF. Login to comment
126 The S1455X mutation was implicated as the cause of the isolated elevated sweat chloride concentrations in the mother and younger daughter based on several lines of evidence. Login to comment
131 Indeed, whole-cell patch-clamp data obtained from IB3-1 bronchial epithelial cells indicate that the chloride channel of S1455X CFTR functions similarly to wild-type CFTR. Login to comment
132 This probably explains why the mother and child carrying the S1455X mutation escaped the pulmonary and pancreatic manifestations of CF. Login to comment
133 However, the remote possibility exists that another undetected mutation on the S1455X allele may contribute to the phenotype. Login to comment
134 Moreover, since the functional data were derived from a heterologous airway epithelial expression system as patient samples were not available for patch-clamp studies, S1455X CFTR dysfunction in vivo may vary in a tissue-specific manner. Login to comment
135 The S1455X mutation is predicted to eliminate a region containing two stretches of amino acids that are highly conserved among species (36-38). Login to comment
137 The phenotype associated with the S1455X mutation indicates that the C-terminal sequences of CFTR have a functional role in the sweat gland. Login to comment
141 Loss of these sequences due to the S1455X mutation prohibits CFTR trafficking to the basolateral surface, leading to reduced chloride permeability of the duct cells and elevated chloride concentrations in the sweat. Login to comment
164 Dot-blots were hybridized at 42_C for 1 h with γ-32P-labeled S1455X mutant probe (5'-CACTTGCTTCAGTT- CCGG-3') or S1455 wild-type probe (5'-ACCGGAACTCAAG- CAAGTG-3'), washed at room temperature and exposed to X-ray film for 10 min at -80_C. Login to comment
166 Expression analysis The mutation S1455X was created in the CFTR-containing vector pBQ4.7 (gift from J. Rommens and L.-C. Tsui; The Hospital for Sick Children, Toronto) by single-strand mutagenesis (48) and then shuttled into the Rous sarcoma virus (RSV)-driven expression vector (pRSV-CFTR) using NcoI and SalI restriction sites common to both plasmids (30). Login to comment
180 Whole-cell patch-clamp recording Whole-cell recordings were performed on IB3-1 cells transiently transfected with either pRSV-CFTR or pRSV-CFTR/S1455X using an inverted Nikon microscope (Nikon, Inc., Melville, NY), an Axopatch amplifier (Axon Instruments, Inc., Foster City, CA) and PCLAMP 6.0 software (Axon Instruments, Inc.). Login to comment
183 IB3-1 cells were transiently transfected at 30% confluency in a 35 mm dish for 6-8 h with either 3 µg of wild-type CFTR (pRSV-CFTR) or 3 µg of CFTR bearing the mutation S1455X (pRSV-CFTR/S1455X) using 15 µl of lipofectin and 1 ml of Opti-MEM. Login to comment
2 We report the identification of a 6.8 kb deletion (del14a) and a nonsense mutation (S1455X) in the CFTR genes of a mother and her youngest daughter with isolated elevated sweat chloride concentrations. Login to comment
6 Loss of this region did not affect processing of transiently expressed S1455X-CFTR compared with wild-type CFTR. Login to comment
8 Preservation of chloride channel function of S1455X-CFTR was consistent with normal lung and pancreatic function in the mother and her daughter. Login to comment
29 Shading indicates CFTR alleles: del14a alleles are solid, S1455X alleles are hatched and the wild-type allele is unshaded. Login to comment
55 Identification of nonsense mutation S1455X in mother and daughter with elevated sweat chloride concentrations Screening for 16 CF mutations common among Caucasians by reverse dot-blot assay did not detect a mutation in any family member. Login to comment
72 This novel mutation is predicted to change the codon for serine at residue 1455 to an opal termination codon, and is designated S1455X.Both theproband`s mother and sister are compound heterozygotes for deletion 14a and S1455X (Fig. 1). Login to comment
75 CFTR mRNA transcript bearing the S1455X mutation is stable RT-PCR was used to determine the consequences of the del14a and S1455X mutations upon transcript splicing and stability. Login to comment
79 Since nonsense mutations frequently cause severe reduction in mRNA levels (28), the stability of mRNA transcripts bearing the nonsense mutation S1455X was assessed as follows. Login to comment
83 Wild-type CFTR and S1455X CFTR proteins immunoprecipitated with the R-domain-specific monoclonal antibody are indicated by the arrow.Both migrateat ~175kDa.TheS1455XCFTRtruncated protein was not detected by immunoprecipitation with the C-terminus-specific antibody. Login to comment
88 To verify this result, we compared the levels of CFTR transcripts bearing S1455X with those missing exon 14a by RT-PCR amplification of exon 24 followed by hybridization with oligonucleotides specific for each transcript. Login to comment
92 The S1455X CFTR truncated protein is processed to a mature state and functions similarly to wild-type CFTR Processing of CFTR bearing S1455X was evaluated by immunoprecipitation using commercially available monoclonal antibodies directed against the R-domain or the last four residues at the C-terminus (Genzyme). Login to comment
95 As expected, the S1455X CFTR mutant truncated at the C-terminus was not immunoprecipitated by the C-terminus antibody (Fig. 4). Login to comment
98 To assay function, wild-type and S1455X CFTRcDNAs were transiently transfected into CF airway epithelial cells (IB3-1) devoid of functional CFTR. Login to comment
100 Whole-cell chloride current activated by cAMP in IB3-1 cells transfected with wild-type CFTR or S1455X CFTR.Current-voltage plots for wild-type CFTR (left) and S1455X CFTR (right) in the presence of CPT-cAMP (200 &#b5;M) are shown as filled symbols. Login to comment
104 Incubation with a non-hydrolyzable form of cAMP (CPT-cAMP; 200 &#b5;M) evoked chloride currents of similar magnitude in wild-type CFTR (+100 mV: 1090.9 &#b1; 84.2 SEM pA; n = 12) and S1455X CFTR (+100 mV: 938.9&#b1; 114.4 pA; n = 20) transfected cells that were significantly higher (P < 0.05) than non-transfected cells (+100 mV: 89.3 &#b1; 34.0 pA; n = 5). Login to comment
108 Thus, S1455X CFTR generates robust cAMP-activated chloride currents similarly to wild-type CFTR. Login to comment
120 The good health of the mother at 46 years of age suggested a very low likelihood that the S1455X/ del14a genotype causes CF. Login to comment
127 The S1455X mutation was implicated as the cause of the isolated elevated sweat chloride concentrations in the mother and younger daughter based on several lines of evidence. Login to comment
136 The S1455X mutation is predicted to eliminate a region containing two stretches of amino acids that are highly conserved among species (36-38). Login to comment
138 The phenotype associated with the S1455X mutation indicates that the C-terminal sequences of CFTR have a functional role in the sweat gland. Login to comment
142 Loss of these sequences due to the S1455X mutation prohibits CFTR trafficking to the basolateral surface, leading to reduced chloride permeability of the duct cells and elevated chloride concentrations in the sweat. Login to comment
165 Dot-blots were hybridized at 42C for 1 h with b3;-32P-labeled S1455X mutant probe (5'-CACTTGCTTCAGTT- CCGG-3') or S1455 wild-type probe (5'-ACCGGAACTCAAG- CAAGTG-3'), washed at room temperature and exposed to X-ray film for 10 min at -80C. Login to comment
167 Expression analysis The mutation S1455X was created in the CFTR-containing vector pBQ4.7 (gift from J. Rommens and L.-C. Tsui; The Hospital for Sick Children, Toronto) by single-strand mutagenesis (48) and then shuttled into the Rous sarcoma virus (RSV)-driven expression vector (pRSV-CFTR) using NcoI and SalI restriction sites common to both plasmids (30). Login to comment
181 Whole-cell patch-clamp recording Whole-cell recordings were performed on IB3-1 cells transiently transfected with either pRSV-CFTR or pRSV-CFTR/S1455X using an inverted Nikon microscope (Nikon, Inc., Melville, NY), an Axopatch amplifier (Axon Instruments, Inc., Foster City, CA) and PCLAMP 6.0 software (Axon Instruments, Inc.). Login to comment
184 IB3-1 cells were transiently transfected at 30% confluency in a 35 mm dish for 6-8 h with either 3 &#b5;g of wild-type CFTR (pRSV-CFTR) or 3 &#b5;g of CFTR bearing the mutation S1455X (pRSV-CFTR/S1455X) using 15 &#b5;l of lipofectin and 1 ml of Opti-MEM. Login to comment

PMID: 11001491 [PubMed] Kleizen B et al: "Regulated trafficking of the CFTR chloride channel."

No. Sentence Comment

47 However, expressing the C-terminally truncated green fluorescent protein (GFP)- CFTR-S1455X construct shifted the CFTR localization to the basolateral membrane, suggesting that the deleted 26 amino acids somehow mask interaction of basolateral targeting signals in the CFTR deletion mutant and thereby prevent basolateral localization (Moyer et al., 1999). Login to comment
49 In light of these studies it would be of interest to assess whether CFTR-S1455X (but not WT-CFTR) has acquired the capacity to interact with the AP-1 complex in cells expressing the novel m1B adaptor subunit (Folsch et al., 1999). Login to comment

PMID: 23276700 [PubMed] Krenkova P et al: "Distribution of CFTR mutations in the Czech population: positive impact of integrated clinical and laboratory expertise, detection of novel/de novo alleles and relevance for related/derived populations."

No. Sentence Comment

56 The S1455X mutation was observed in compound heterozygosity with the F508del in a male patient who was clinically diagnosed at age 7 years, in which "repeated bronchitis" led to sweat testing (mean concentration 70 mmol/l). Login to comment
57 Interestingly, the patient's asymptomatic father bears mutation S1455X in trans to a novel variant S1456N and the patient's apparently healthy brother has the maternal-F508del/S1456N genotype. Login to comment
76 We have not included the male with the S1455X/F508del in our cohort, since he only suffers from "isolated elevated sweat chloride concentrations" [20] and does not meet the diagnostic criteria for CF [10]. Login to comment

PMID: 25304080 [PubMed] Dell'Edera D et al: "Analysis of cystic fibrosis gene mutations in children with cystic fibrosis and in 964 infertile couples within the region of Basilicata, Italy: a research study."

No. Sentence Comment

59 As mentioned before, molecular screening Table 2 Comparison between the results obtained in this study and those obtained in a previous study Castaldo et al. [14] Mutations observed in the present study F508del 55.8% (29) 48.62% (141) N1303K 3.8% (2) 9.31% (27) G542X 3.8% (2) 8.96% (26) W1282X 3.8% (2) 1.03% (3) 2183AA>G 5.8% (3) 2.76% (8) R1162X 0 0 1717-1G>A 1.9% (1) 0 T338I 0 0 R347P 0 0.69% (2) 711+5G>A 0 0 852del22 5.8% (3) 1.03% (3) 4382delA 0 0.69% (2) 1259insA 0 0.34% (1) 4016insT 0 0.34% (1) R553X 0 0.34% (1) R1158X 0 0 L1077P 0 1.03% (3) I502T 0 0 3849+10kbC>T 1.9% (1) 0.34% (1) D579G 0 0.69% (2) G1244E 3.8% (2) 0 G1349D 0 0.34% (1) 2789+5G>A 0 1.03% (3) 711+1G>T 0 0 L1065P 0 0 2522insC 0 0 E585X 0 0 G85E 0 0 G178R 0 0 D1152H 0 3.10% (9) I148T-3195del6 0 0 I148T (alone) 0 4.48% (13) R334W 0 0 DI507 0 0.69% (2) I1005R 0 0 3272-26A>G 0 0 2711delT 0 0 L558S 1.9% (1) 0.34% (1) W1063X 0 0 D110H 0 0 S549R (A>C) 1.9% (1) 0.69% (2) 2184insA 0 0 3131del22 0 0 Table 2 Comparison between the results obtained in this study and those obtained in a previous study (Continued) R709N 0 0 A349V 0 0 4015insA 0 0 Y849X 1.9% (1) 0.34% (1) G551D 0 1.03% (3) 621+3A>G 0 0.34% (1) E831X 0 0 I507del 0 0.69% (2) IVS8 TG12/t5 0 1.03% (3) H139R (A->G) 0 0.34% (1) 1248+1G>A 0 0.34% (1) R74W;V201M;D1270N 0 0.69% (2) S1455X 0 0.34% (1) dele 2,3 (21kb) 0 0.34% (1) 991del5 0 0.34% (1) UNKNOWN 7 %(4) 4.83% (14) F508C 0 0.69% (2) TOTAL 52 290 of CF is highly recommended in the USA by the National Institutes of Health Consensus Development Conference Statement on genetic testing for cystic fibrosis [17]. Login to comment

PMID: 25910067 [PubMed] Lucarelli M et al: "A Genotypic-Oriented View of CFTR Genetics Highlights Specific Mutational Patterns Underlying Clinical Macrocategories of Cystic Fibrosis."

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390 L1077P c.3230T>C CF-PI CF-causing p.Leu1077Pro Y1092X(C>A) c.3276C>A CF-PI CF-causing p.Tyr1092* M1137V c.3409A>G CFTR-RD nd p.Met1137Val D1152H c.3454G>C CF-PI,CF-PS,CFTR-RD varying clinical consequence p.Asp1152His R1162X c.3484C>T CF-PI CF-causing p.Arg1162* D1168G c.3503A>G CFTR-RD nd p.Asp1168Gly 3667ins4 c.3535_3536insTCAA CF-PI CF-causing p.Thr1179IlefsX17 S1206X c.3617C>A uncertain: CF-PI and/or CF-PS nd p.Ser1206* I1234V c.3700A>G CF-PI,CF-PS CF-causing p.Ile1234Val S1235R c.3705T>G CFTR-RD non CF-causing p.Ser1235Arg 3849+10kbC>T c.3717+12191C>T CF-PI,CF-PS CF-causing V1240G c.3719T>G CFTR-RD nd p.Val1240Gly G1244R c.3730G>A uncertain: CF-PI and/or CF-PS nd p.Gly1244Arg G1244E c.3731G>A CF-PI,CF-PS CF-causing p.Gly1244Glu G1247R(G>C) c.3739G>C CF-PS nd p.Gly1247Arg W1282X c.3846G>A CF-PI CF-causing p.Trp1282* Q1291R c.3872A>G CF-PI,CF-PS,CFTR-RD nd p.Gln1291Arg 4016insT c.3884_3885insT CF-PI CF-causing p.Ser1297PhefsX5 4040delA c.3908delA CF-PI nd p.Asn1303ThrfsX25 N1303K c.3909C>G CF-PI CF-causing p.Asn1303Lys ex22-24del c.3964-3890_4443+3143del9454ins5 CF-PI nd ex22,23del c.3964-78_4242+577del1532 CF-PI CF-causing 4168delCTAAGCC c.4036_4042del CF-PI nd p.Leu1346MetfsX6 G1349D c.4046G>A CF-PI CF-causing p.Gly1349Asp H1375P c.4124A>C uncertain: CF-PI and/or CF-PS nd p.His1375Pro S1455X c.4364C>G CF-PS,CFTR-RD nd p.Ser1455* Q1476X c.4426C>T CFTR-RD nd p.Gln1476* nd,Not determined.According to the three rules described (see Materials and Methods),each mutated allele was classified according to its clinical outcome.It was impossible to univocally assign 16 of the 125 different mutated alleles to one or more macrocategories.A comparison with the CFTR2 project (11) (http://www.cftr2.org) is shown.The alleles are ordered according to their nucleotidic position. Login to comment

PMID: 25963003 [PubMed] Ooi CY et al: "Inconclusive diagnosis of cystic fibrosis after newborn screening."

No. Sentence Comment

103 In combination with a disease-causing mutation, R117H-7T has been associated with diagnostic uncertainties in CF, TABLE 2 Genotypes of Subjects With CFSPID According to Initial Sweat Chloride Measurements Sweat Chloride ,30 mmol/L Sweat Chloride 30-59 mmol/L Allele 1 Allele 2 n Allele 1 Allele 2 n F508dela R117H (7T)b 9 F508dela R117Cd 2c F508dela 5Tb 2 F508dela L206Wd 2c F508dela D1152Hb 2 F508dela P67Ld 1c F508dela R117Hb 1 F508dela 5Tb 8 F508dela D1270Nb 1 F508dela R117H (7T)b 3 F508dela L997F 3 F508dela R117Hb 3 F508dela 1716G.A 1 F508dela S1455X 1c F508dela 621+3G.A 1 F508dela R170H 1 F508dela I1328T 1 F508dela I148T 1 F508dela L967S 1 F508dela L997F 1 F508dela M1137T 1 F508dela Q1476X 1 F508dela Y301C 1 F508dela S1235R 1 1717-1G.Aa D1152Hb 1 F508dela T1299I 1 2183AA.Ga 5Tb 1 2183AA.Ga R117Cd 1 2183AA.Ga S431G 1 2789+5G.Aa R117H (7T)b 1 3849+10kbC.Ta 3041-15T.G 1 3849+10kbC.Ta 3041-15T.G 1 621+1G.Ta R117H (7T)b 1 621+1G.Ta G1069Rb 1 711+1G.Ta D1152Hb 1 G542Xa L206Wd 1c G542Xa R117H (7T)b 1 G542Xa C1410T 1 G542Xa D1152Hb 1 G551Da 5Tb 1 G551Da D1152Hb 1 N1303Ka 5Tb 1 N1303Ka D1152Hb 1 R1162Xa R117H (7T)b 1c N1303Ka E527G 1 R553Xa 5Tb 1 R117H (5T)a 5Tb 1 R553Xa L997F 1 R117H (7T)b R117H (7T)b 1 R560Ta G576A 1 R117H (7T)b 3041_71G.C 1 W1282Xa 5Tb 2 R117Hb Q1476X 1 F508dela - 2 R117H (5T)a - 1 -, no mutation identified on the second allele. Login to comment
108 TABLE 3 Characteristics of Subjects With CFSPID Who Later Met Diagnostic Criteria of CF Subject Number Allele 1 Allele 2 Ethnicity NBS IRT, mg/L Initial Sweat Chloride, mmol/L Highest Sweat Chloride, mmol/L Country 1 F508del R117C White 105.8 36 61 Canada 2 F508del S1455X White 66.6 46 74 Canada 3 F508del P67L White 151.2 38 38 Canada 4 F508del L206W White 83.8 58 64 Canada 5 G542X L206W White 67 49 66 Canada 6 F508del L206W White 59.9 45 45 Canada 7 R1162X R117H-7T White 126 36 70 Italy 8 2183AA.G R117C White 129 32 32 Italy 9 F508del R117C White 80.4 48 56 Canada e OOI et al including in newborn-screened infants with equivocal CF diagnosis and in older individuals with single-organ manifestations of CF.17,18,20-22 As in the case of the 7 subjects who were initially classified as CFSPID but who were subsequently recognized to carry 2 disease-causing mutations on the basis of the CFTR2 project, the diagnostic consequences (benign versus disease-causing) of the CFTR mutations identified in all of the other subjects with CFSPID may not be apparent until later on, when new genetic information becomes available and classification of CFTR mutations currently considered to be of "unknown" consequences is updated. Login to comment