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Different mechanisms preclude mutant CLDN14 proteins from forming tight junctions in vitro
Marie Wattenhofer1, Alexandre Reymond, Véronique Falciola
1Department of Genetic Medicine and Development, University of Geneva Medical School and Geneva University Hospitals, Geneva, Switzerland.
Human Mutation
|May 10, 2005
Summary
Mutations in claudin 14 (CLDN14) cause deafness by preventing the formation of essential tight junctions in hair cells. This study reveals how specific CLDN14 mutations disrupt these crucial cellular structures, impacting hearing.
Area of Science:
- Genetics
- Cell Biology
- Otolaryngology
Background:
- Nonsyndromic deafness DFNB29 in humans is linked to mutations in the claudin 14 (CLDN14) gene.
- A murine model suggests hair cell degeneration due to cation overload, but the precise mechanism remains unclear.
Purpose of the Study:
- To investigate the mechanism by which CLDN14 mutations lead to hearing loss.
- To compare the function of wild-type and mutant CLDN14 in forming tight junctions.
Main Methods:
- Ectopic expression of wild-type and mutant CLDN14 in mouse fibroblasts (LM cells).
- Analysis of tight junction formation and protein localization at the plasma membrane.
- Identification of alternative spliced transcripts of CLDN14.
Main Results:
- Wild-type CLDN14 induced tight junction formation, while two missense mutants (p.V85D and p.G101R) failed to do so.
- Mutant CLDN14 proteins exhibited differential abilities to localize at the plasma membrane.
- Alternative spliced CLDN14 transcripts were identified, suggesting complex regulation.
Conclusions:
- CLDN14 mutations impair tight junction formation through distinct mechanisms.
- Proper recruitment of CLDN14 to tight junctions is essential for maintaining the hearing process.
- Understanding these mechanisms can inform future therapeutic strategies for deafness.