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Different mechanisms preclude mutant CLDN14 proteins from forming tight junctions in vitro
Author(s) -
Wattenhofer Marie,
Reymond Alexandre,
Falciola Véronique,
Charollais Anne,
Caille Dorothée,
Borel Christelle,
Lyle Robert,
Estivill Xavier,
Petersen Michael B.,
Meda Paolo,
Antonarakis Stylianos E.
Publication year - 2005
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.20172
Subject(s) - tight junction , biology , mutant , missense mutation , phenotype , microbiology and biotechnology , mutation , genetics , ectopic expression , mutant protein , exon , wild type , gene
Mutations in claudin 14 ( CLDN14 ) cause nonsyndromic DFNB29 deafness in humans. The analysis of a murine model indicated that this phenotype is associated with degeneration of hair cells, possibly due to cation overload. However, the mechanism linking these alterations to CLDN14 mutations is unknown. To investigate this mechanism, we compared the ability of wild‐type and missense mutant CLDN14 to form tight junctions. Ectopic expression in L mouse fibroblasts (LM cells) of wild‐type CLDN14 protein induced the formation of tight junctions, while both the c.254T>A (p.V85D) mutant, previously identified in a Pakistani family, and the c.301 G>A (p.G101R) mutant, identified in this study through the screen of 183 Spanish and Greek patients affected with sporadic nonsyndromic deafness, failed to form such junctions. However, the two mutant proteins differed in their ability to localize at the plasma membrane. We further identified hitherto undescribed exons of CLDN14 that are utilized in alternative spliced transcripts. We demonstrated that different mutations of CLDN14 impaired by different mechanisms the ability of the protein to form tight junctions. Our results indicate that the ability of CLDN14 to be recruited to these junctions is crucial for the hearing process. Hum Mutat 25:543–549, 2005. © 2005 Wiley‐Liss, Inc.