Class VI unconventional myosin is required for spermatogenesis in Drosophila
Class VI unconventional myosin is required for spermatogenesis in Drosophila
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DOI：
10.1091/mbc.10.12.4341
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发表时间：
1999-12-01
影响因子：
3.3
通讯作者：
Bownes, M
中科院分区：
文献类型：
--
作者：
Hicks, JL;Deng, WM;Bownes, M
我们已经鉴定出VI类非常规肌球蛋白（95F肌球蛋白）存在功能部分缺失的突变，这种突变导致雄性不育。在精子发生过程中，生殖系前体细胞经历有丝分裂和减数分裂，形成一束64个精细胞。这些精细胞通过细胞质桥相互连接，直到个体化过程发生。个体化过程涉及在精细胞核周围形成一种由细胞骨架蛋白和膜构成的复合物，即个体化复合物（IC）。这种复合物贯穿每个精细胞的长度，将共享的膜分解为包围每个精细胞的单层膜。我们已经确定95F肌球蛋白是IC的一个组成部分，其功能对个体化至关重要。在野生型睾丸中，95F肌球蛋白定位于IC的前沿。95F肌球蛋白的两个独立突变仅在包括睾丸在内的一部分组织中减少了95F肌球蛋白的量。95F肌球蛋白的这种减少由于精细胞个体化缺陷导致雄性不育。用95F肌球蛋白重链cDNA进行生殖系转化可挽救雄性不育表型。在这些95F肌球蛋白突变体中，IC的运动异常，这表明95F肌球蛋白在IC运动中起关键作用。本报告是首次鉴定出除肌动蛋白之外的IC组成成分。我们提出95F肌球蛋白是一种在个体化过程中参与膜重组的动力蛋白。
We have identified partial loss of function mutations in class VI unconventional myosin, 95F myosin, which results in male sterility. During spermatogenesis the germ line precursor cells undergo mitosis and meiosis to form a bundle of 64 Spermatids. The spermatids remain interconnected by cytoplasmic bridges until individualization. The process of individualization involves the formation of a complex of cytoskeletal proteins and membrane, the individualization complex (IC), around the spermatid nuclei. This complex,traverses the length of each spermatid resolving the shared membrane into a single membrane enclosing each spermatid. We have determined that 95F myosin is a component of the IC whose function is essential for individualization. In wild-type testes, 95F myosin localizes to the leading edge of the IC. Two independent mutations in 95F myosin reduce the amount of 95F myosin in only a subset of tissues, including the testes. This reduction of 95F myosin causes male sterility as a result of defects in spermatid individualization. Germ line transformation with the 95F myosin heavy chain cDNA rescues the male sterility phenotype. IC movement is aberrant:in these 95F myosin mutants, indicating a critical role for 95F myosin in IC movement. This report is the first identification of a component of the IC other than actin. We propose that 95F myosin is a motor that participates in membrane reorganization during individualization.