Gap junctional communication during zebrafish fin growth

描述（由申请人提供）：斑马鱼鳍为揭示控制大小和形状的分子机制提供了极好的模型系统。鳍的生长是通过在鳍条的末端增加骨节来实现的。因此，产生短节的鳍长突变体可以识别调节骨形态发生的分子。事实上，短鳍突变体产生短鳍条片段，这种表型是由斑马鱼连接蛋白43突变引起的。有趣的是，人类连接蛋白43的突变导致眼齿指发育不良，这是一种导致颅面和肢体畸形的综合征。因此，连接蛋白43控制着斑马鱼和人类真皮骨的形态，因此可能在这些组织的大小和形状的调节中发挥类似的作用。该建议的潜在目标是将连接蛋白43的功能与节段形态发生的细胞和分子事件相关联。这将通过四个目标来实现。首先，将产生几个新的连接蛋白43等位基因，其修饰或限制间隙连接细胞间通讯。其次，在细胞-细胞通讯的异源测定中，将在连接蛋白43的不同等位基因中监测间隙连接通讯。第三，连接蛋白43的表达将被监测的节段形态发生所需的细胞事件，如细胞增殖和成骨细胞分化。最后，短片段的细胞基础将通过监测短鳍突变体中的这些过程来检查。因此，该建议的目的将提供直接的见解控制骨节生长在斑马鱼。此外，这些见解将直接促进未来对人类骨畸形生物学的理解。

DESCRIPTION (provided by applicant): Zebrafish fins provide an excellent model system for revealing the molecular mechanisms controlling size and shape. Fins grow by the addition of bony segments to the distal ends of growing fin rays. Therefore, fin length mutants that produce short segments may identify molecules that regulate bone morphogenesis. Indeed, the short fin mutant produces short fin ray segments, and this phenotype is caused by mutations in zebrafish connexin43. Interestingly, mutations in human connexin43 cause oculodentodigital dysplasia, a syndrome which results in craniofacial and limb malformations. Thus, connexin43 controls the morphology of dermal bone in both zebrafish and humans, and may therefore play similar roles in the regulation of size and shape in these tissues. The underlying goal of this proposal is to correlate the function of connexin43 with the cellular and molecular events of segment morphogenesis. This will be accomplished by four aims. First, several new alleles of connexin43 that modify or limit gap junction intercellular communication will be generated. Second, gap junction communication will be monitored in different alleles of connexin43 in a heterologous assay for cell-cell communication. Third, connexin43 expression will be monitored with respect to the cellular events required for segment morphogenesis, such as cell proliferation and osteoblast differentiation. Finally, the cellular basis for short segments will be examined by monitoring these processes in short fin mutants. Thus, the aims of this proposal will provide immediate insights into the control of bony segment growth in zebrafish. Furthermore, these insights will directly facilitate future understanding of the biology of human bone malformations.