Electrical coupling of body-wall muscle cells of C. elegans

大多数无脊椎动物和脊椎动物组织的相邻细胞可以通过称为间隙连接的细胞间通道相互通信。间隙连接在细胞发育和细胞功能中起着重要作用。间隙连接蛋白的突变可能导致多种疾病，包括脱髓鞘、耳聋、女性不育、白内障、心律失常或畸形、胚胎致死，以及可能的癌症。缝隙连接可由连接蛋白、内连接蛋白和泛连接蛋白组成。虽然这三个蛋白家族在一级序列上是不同的，但它们形成的间隙连接具有主要的结构和功能特性。同一家族的间隙连接蛋白可以自组装或共组装形成间隙连接，并定位到特定的亚细胞结构域。亚基特异性组装和适当的亚细胞定位对间隙连接的功能至关重要。然而，人们对它们的机制知之甚少。本研究的目的是利用秀丽隐杆线虫体壁肌肉作为模型系统(1)鉴定表达的间隙连接蛋白，并评估其在电偶联和运动中的作用；(2)通过共免疫染色、不同荧光蛋白标记和非洲爪蟾卵母细胞共表达来确定所鉴定的间隙连接蛋白是自组装还是共组装成间隙连接；(3)分离出绿色荧光蛋白标记的间隙连接蛋白亚细胞错定位的突变体，以便在后续研究中通过对突变体的分析来鉴定介导间隙连接亚细胞定位的蛋白。长期目标是了解功能，亚单位特异性组装和亚细胞定位缝隙连接的机制。

Neighboring cells of most invertebrate and vertebrate tissues can communicate with each other through intercellular channels called gap junctions. Gap junctions play important roles in development and cellular functions. Mutations of gap junction proteins may cause a variety of diseases, including demyelination, deafness, female infertility, cataracts, cardiac arrhythmias or malformation, embryonic lethality, and possibly cancer.Gap junctions may be formed by connexins, innexins, and pannexins. Although the three families of proteins are distinct in primary sequence, gap junctions formed by them share major structural and functional properties. Gap junction proteins of the same family may self-assemble or co-assemble to form gap junctions, and get localized to specific subcellular domains. Subunit-specific assembly and appropriate subcellular localization are critical to the function of gap junctions. However, their mechanisms are poorly understood. The aims of this proposal are to use the nematode Caenorhabditis elegans body-wall muscle as a model system to (1) identify gap junction proteins expressed, and evaluate their roles in electrical coupling and locomotion; (2) determine if the identified gap junction proteins self-assemble or co-assemble into gap junctions by coimmunostaining, labeling with distinct fluorescent proteins, and co-expression in Xenopus oocytes; and (3) isolate mutants showing subcellular mislocalization of a green fluorescent protein-tagged gap junction protein so that proteins mediating gap junction subcellular localization may be identified through analyses of the mutants in subsequent studies. The long-term goal is to understand functions, subunit-specific assembly, and mechanisms of subcellular localization of gap junctions.