Gap junctional communication during zebrafish fin growth

描述（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一个很好的模型系统。鳍的生长是通过在生长中的鳍的远端增加骨段来实现的。因此，产生短片段的鳍长突变可能识别调节骨形态发生的分子。事实上，短鳍突变体产生短鳍射线片段，这种表型是由斑马鱼连接蛋白突变引起的43。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，connexin43控制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。这一提议的潜在目标是将connexin43的功能与细胞和分子的片段形态发生事件联系起来。这将通过四个目标来实现。首先，connexin43的几个新的等位基因会改变或限制间隙连接的细胞间通讯。其次，在细胞-细胞通信的异源分析中，将监测connexin43的不同等位基因中的间隙连接通信。第三，connexin43的表达将与细胞片段形态发生所需的细胞事件（如细胞增殖和成骨细胞分化）相关。最后，将通过监测短鳍突变体的这些过程来检查短片段的细胞基础。因此，本提案的目的将为斑马鱼骨段生长的控制提供直接的见解。此外，这些见解将直接促进未来对人类骨骼畸形生物学的理解。

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.