ANALYSIS OF ANIMAL NON MUSCLE HEAVY CHAIN GENE

非肌肉 (nm) 肌球蛋白是细胞骨架的重要组成部分，是一种复杂的细胞骨架 协调胞质分裂等细胞功能的细胞内网络， 运动和肌肉收缩。 最近的工作表明 缺乏肌球蛋白重链 (MHC) 的盘基网柄菌具有活力、能动性和 吞噬细胞，尽管它们表现出明显异常的胞质分裂。 在 哺乳动物细胞分裂期间，nm 肌球蛋白定位于卵裂沟 胞质分裂；标记的肌球蛋白轻链显微注射到活细胞中 定位于乳沟沟，并重新融入压力 胞质分裂完成时的纤维。 Nm 肌球蛋白也可能是必要的 对于肌节组装，因为细胞骨架必须充当支架 用于合成肌节收缩蛋白 共翻译组装。 基因靶向领域令人兴奋的进展现在使得靶向 通过同源重组产生不可选择的基因。 初步数据表明 nm mhc 基因是由一个或几个基因编码的 目标定位可行。 该项目的主要目标是完成 nm mhc 基因的克隆和表征，以便开始基因 通过同源重组进行破坏实验。 通过破坏纳米 mhc在小鼠非和肌肉细胞中的作用，我们应该能够阐明其作用 nm mhc 在胞质分裂、细胞运动和肌节组装中的作用。 进一步 研究将侧重于识别那些赋予特定功能的基因域 对肌肉和非肌肉中的 nm mhc 蛋白起作用。

Nonmuscle (nm) myosin is an essential part of the cytoskeleton, a complex intracellular network that orchestrates such cell functions as cytokinesis, motility, and muscle contraction. Recent work has demonstrated that dictyostelium lacking myosin heavy chain (mhc) are viable, motile, and phagocytic, although they demonstrate markedly abnormal cytokinesis. In dividing mammalian cells, nm myosin localizes to the cleavage furrow during cytokinesis; labeled myosin light chains microinjected into living cells localize in the cleavage furrow, and become reincorporated into stress fibers at the completion of cytokinesis. Nm myosin may also be necessary for sarcomere assembly, because the cytoskeleton must act as a scaffolding for synthesis of the sarcomeric contractile proteins to occur by cotranslational assembly. Exciting advances in gene targeting now make it possible to target nonselectable genes by homologous recombination. Preliminary data suggests that the nm mhc gene is encoded by one or a few genes making such gene targeting feasible. The primary goal of this project is to complete the cloning and characterization of the nm mhc gene, in order to begin gene disruption experiments by homologous recombination. By disrupting the nm mhc in mouse non and muscle cells, we should be able to elucidate the role of nm mhc in cytokinesis, cell motility and sarcomere assembly. Further studies will focus on identifying those gene domains that confer specific functions to the nm mhc protein in both muscle and nonmuscle.