Abstract
The COCH gene mutated in autosomal dominant sensorineural deafness (DFNA9) encodes cochlin, a major constituent of the inner ear extracellular matrix. Sequence analysis of cochlin from DFNA9 patients identified five distinct single-amino-acid mutations within a conserved region (the LCCL domain) of cochlin. To define the molecular basis of DFNA9, we have generated myc-tagged wild-type and mutant cochlins and explored their behavior in transient transfection systems. Western blotting of cell lysates and culture media indicates that wild-type and mutant cochlins are synthesized and secreted in similar amounts. Immunofluorescent staining confirms that all are detected within the endoplasmic reticulum and the Golgi complex of transfected cells. Our findings suggest that COCH mutations are unlikely to cause abnormalities in secretion and suggest that extracellular events might cause DFNA9 pathology. In agreement, we show that wild-type cochlin accumulates in extracellular deposits that closely parallel the matrix component fibronectin, whereas mutant cochlins vary in the amount and pattern of extracellular material. Whereas some mutants exhibit an almost normal deposition pattern, some show complete lack of deposition. Our results suggest that DFNA9 results from gene products that fail to integrate correctly into the extracellular matrix. The partial or complete penetrance of integration defects suggests that DFNA9 pathology may be caused by multiple molecular mechanisms, including compromised ability of cochlin to self-assemble or to form appropriate complexes with other matrix components.
Similar content being viewed by others
References
Barroso M, Nelson D, Sztul ES (1995) TAP/p115, a general "fusion" factor is homologous to yeast USO1 and is required for stable binding of vesicles to target membrane. Proc Natl Acad Sci USA 92:527–531
Cooper DN, Nussbaum RL, Krawczak M (2002) Proposed guidelines for papers describing DNA polymorphism-disease associations. Hum Genet 110:207–208
Dunnen JT den, Antonarakis SE (2001) Nomenclature for the description of human sequence variations. Hum Genet 109:121–124
Fassio A, Sitia R (2002) Formation, isomerisation and reduction of disulphide bonds during protein quality control in the endoplasmic reticulum. Histochem Cell Biol 117:151–157
Fransen E, Verstreken M, Verhagen WIM, Wuyts FL, Huygen PLM, D'Haese P, Robertson NG, Morton CC, McGuirt WT, Smith RJH, Declau F, Heyning PH van de, Camp G van (1999) High prevalence of symptoms of Meniére's disease in three families with a mutation in the COCH gene. Hum Mol Genet 8:1425–1429
Gao Y, Alvarez C, Nelson D, Sztul ES (1998) Molecular cloning, characterization and dynamics of rat formimino-transferase cyclo-deaminase, a Golgi associated 58 K protein. J Biol Chem 273:33825–33834
Hampton RY (2002) ER-associated degradation in protein quality control and cellular regulation. Curr Opin Cell Biol 14:476–482
Ikezono T, Omori A, Ichinose S, Pawankar R, Watanabe A, Yagi T (2001) Identification of the protein product of the Coch gene (hereditary deafness gene) as the major component of bovine inner ear protein. Biochim Biophys Acta 1535:258–265
Kamarinos M, McGill J, Lynch M, Dahl H (2001) Identification of a novel COCH mutation, 1109 N highlights the similar clinical features observed in DFNA9 families. Hum Mutat (Mutat Brief) 408:1–6
Khetarpal U (2000) DFNA9 is a progressive audiovestibular dysfunction with a microfibrillar deposit in the inner ear. Laryngoscope 110:1379–1384
Kok YJM de, Bom SJH, Brunt TM, Kemperman MH, Beusekom E van, Velde-Visser SD van der, Robertson NG, Morton CC, Huygen PLM, Verhagen WIM, Brunner HG, Cremers CWRJ, Cremers FPM (1999) A Pro51Ser mutation in the COCH gene is associated with late onset autosomal dominant progressive sensorineural hearing loss with vestibular defects. Hum Mol Genet 8:361–366
Liepinsh E, Trexler M, Kaikkonen A, Weigelt J, Banyai L, Patthy L, Otting G (2001) NMR structure of the LCCL domain and implications for DFNA9 deafness disorder. EMBO J 20:5347–5353
Manolis EN, Yandavi N, Nadol JB Jr, Eavey RD, McKenna M, Rosenbaum S, Khetarpal U, Halpin C, Merchant SN, Duyk GM, MacRae C, Seidman CE, Seidman JG (1996) A gene for non-syndromic autosomal dominant progressive postlingual sensorineural hearing loss maps to chromosome 14q12–13. Hum Mol Genet 5:1047–1050
Mayne R, Ren ZX, Liu J, Cook T, Carson M, Narayana S (1999) VIT-1: the second member of a new branch of the von Willebrand factor A domain superfamily. Biochem Soc Trans 27:832–835
Merchant SN, Linthicum FH, Nadol JB Jr (2000) Histopathology of the inner ear in DFNA9. Adv Otorhinolaryngol 56:212–217
Nelson D, Alvarez C, Gao Y, Garcia-Mata R, Fialkowski E, Sztul ES (1998) The membrane transport factor TAP/p115 cycles between the Golgi and earlier secretory compartments and contains distinct domains required for its localization and function. J Cell Biol 143:319–331
Petersen MB (2002) Non-syndromic autosomal-dominant deafness. Clin Genet 62:1–13
Povey S, Lovering R, Bruford E, Wright M, Lush M, Wain H (2001) The HUGO Gene Nomenclature Committee (HGNC). Hum Genet 109:678–680
Robertson NG, Skvorak AB, Yin Y, Weremowicz S, Johnson KR, Kovatch KA, Battey JF, Bieber FR, Morton CC (1997) Mapping and characterization of a novel cochlear gene in human and in mouse: a positional candidate gene for a deafness disorder, DFNA9. Genomics 46:345–354
Robertson NG, Lu L, Heller S, Merchant SN, Eavey RD, McKenna M, Nadol JB Jr, Miyamoto RT, Linthicum FH Jr, Lubianca Neto JF, Hudspeth AJ, Seidman CE, Morton CC, Seidman JG (1998) Mutations in a novel cochlear gene cause DFNA9, a human nonsyndromic deafness with vestibular dysfunction. Nat Genet 20:299–303
Robertson NG, Resendes BL, Lin JS, Lee C, Aster JC, Adams JC, Morton CC (2001) Inner ear localization of mRNA and protein products of COCH, mutated in the sensorineural deafness and vestibular disorder, DFNA9. Hum Mol Genet 10:2493–2500
Steel KP, Bussoli TJ (2001) Deafness genes: expressions of surprise. Otorhinolaryngology 100:10–20
Trexler M, Banyai L, Patthy L (2000) The LCCL module. Eur J Biochem 267:5751–5757
Verhagen WIM, Bom SJH, Huygen PLM, Fransen E, Camp G van, Cremers CWRJ (2000) Familial progressive vestibulocochlear dysfunction caused by a COCH mutation (DFNA9). Arch Neurol 57:1045–1047
Verhagen WIM, Bom SJH, Fransen E, Camp G van, Huygen PLM, Theunissen EJJM, Cremers CWRJ (2001) Hereditary cochleovestibular dysfunction due to a COCH gene mutation (DFNA9): a follow-up study of a family. Clin Otolaryngol 26:477–483
Verstreken M, Declau F, Wuyts FL, Haese PD, Camp G van, Fransen E, Hauwe V, Buyle S, Smets REM, Feenstra L,Stappen A van der, Heyning PH van de (2001) Hereditary otovestibular dysfunction and Meniere's disease in the large Belgian family is caused by a missense mutation in the COCH gene. Otol Neurotol 22:874–881
Acknowledgements
We thank Dr. Cynthia Morton and Nancy Robertson for helpful discussion and sharing of results prior to publication. We are grateful to Dr. Anne Woods for providing antibodies and explanations and to Dr. Ben Sha for modeling the LCCL domain.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Grabski, R., Szul, T., Sasaki, T. et al. Mutations in COCH that result in non-syndromic autosomal dominant deafness (DFNA9) affect matrix deposition of cochlin. Hum Genet 113, 406–416 (2003). https://doi.org/10.1007/s00439-003-0992-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00439-003-0992-7