| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
We have performed a proteomic analysis of the inner ear proteins using 2D-GE. In the process of analysis, we have found very unique properties of the COCH gene product. The COCH gene mutated in DFNA9, an autosomal dominant hereditary sensorineural hearing loss and vestibular disorder, encodes cochlin. DFNA9 patients show symptoms such as episodes of vertigo, tinnitus, aural fullness and hearing loss. Clinically, these symptoms are consistent with the criteria for Meniere's disease. COCH is the only gene, identified so far, whose mutation leads to the symptoms of Meniere's disease in a significant portion of the carriers.
We showed Cochlin constitutes 70% of inner ear proteins, and identified three cochlin isoforms in the inner ear tissue, p63s, p44s and p40s, which exhibit significant molecular heterogeneity. Structure analysis of Cochlin isoforms showed that the mutations influence only the full-length isoform of Cochlin (p63s), and not the processed Cochlin isoforms (p44s and p40s), which do not contain the LCCL domain. What happens to the LCCL domain once it is cleaved from full-length Cochlin was an open issue.
We further characterized the expression and structure of Cochlin isoforms by isoform-specific antibodies that recognize three distinct domains. We have detected a set of three Cochlin isoforms only in the inner ear tissue and the expression of full length Cochlin P63 is inner ear specific.
The specificity of the expression of COCH gene in the inner ear suggests that the promoter and enhancer of COCH gene can be used for the inner ear specific gene targeting. We have cloned 800bp upstream of COCH gene and now we are analysing the promoter activity by tranfection study.
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