Genetic analysis of the function and development of the inner ear pigment cells essential for hearing acuity.

点击翻译按钮获取中文摘要

Little is known about the molecular mechanisms by which melanocytes, developed from neural crest cells, play an essential role in hearing acuity. The aim of this study is to elucidate the gene expression profile of the mouse inner ear affected by differentiation of the inner ear melanocytes and to infer the evolution of this melanocyte-envolved inner ear system. First, we found that inner ear melanocytes produce black melanin irrelevant to the coat color of mice. Next, we made two cDNA libraries prepared from the stria vascularis and its surrounding area of the inner ear obtained from wild type mouse and Mitf^<mi-bw> mutant mouse that shows aberrant pigmentation and hearing loss due to the failure of melanocyte differentiation. Then we obtained a subtraction library between those libraries. Differential screening was also carried out using this subtracted library. Micro array analysis of gene expression in each strain was also performed. Expression of many clones that showed differential expression in these two mouse strains was analyzed using in situ hybridization. Strangely enough, many of clones did not show significant in situ signals in each strain, nor many other clones showed prominent differences in expression between these two strains. Still, there were several clones express differentially and some of them did not express in the melanocytes but in their surrounding tissues. Although we need to analyze the sequence structure of these clones in detail, one putative gene seems to be involved in. stress reaction in melanocytes and another one seems to share a conserved roll with ascidian brain pigment cells that play as sensory organs. Functional analysis of these genes should be very important in future.