Boylan Kristin L M, Hays Thomas S
University of Minnesota, Department of Genetics, Cell Biology and Development, Minneapolis 55455, USA.
Genetics. 2002 Nov;162(3):1211-20. doi: 10.1093/genetics/162.3.1211.
The microtubule motor cytoplasmic dynein powers a variety of intracellular transport events that are essential for cellular and developmental processes. A current hypothesis is that the accessory subunits of the dynein complex are important for the specialization of cytoplasmic dynein function. In a genetic approach to understanding the range of dynein functions and the contribution of the different subunits to dynein motor function and regulation, we have identified mutations in the gene for the cytoplasmic dynein intermediate chain, Dic19C. We used a functional Dic transgene in a genetic screen to recover X-linked lethal mutations that require this transgene for viability. Three Dic mutations were identified and characterized. All three Dic alleles result in larval lethality, demonstrating that the intermediate chain serves an essential function in Drosophila. Like a deficiency that removes Dic19C, the Dic mutations dominantly enhance the rough eye phenotype of Glued(1), a dominant mutation in the gene for the p150 subunit of the dynactin complex, a dynein activator. Additionally, we used complementation analysis to identify an existing mutation, shortwing (sw), as an allele of the dynein intermediate chain gene. Unlike the Dic alleles isolated de novo, shortwing is homozygous viable and exhibits recessive and temperature-sensitive defects in eye and wing development. These phenotypes are rescued by the wild-type Dic transgene, indicating that shortwing is a viable allele of the dynein intermediate chain gene and revealing a novel role for dynein function during wing development.
微管马达胞质动力蛋白驱动着多种细胞内运输活动，这些活动对于细胞和发育过程至关重要。当前的一种假说认为，动力蛋白复合体的辅助亚基对于胞质动力蛋白功能的特化很重要。在一种旨在了解动力蛋白功能范围以及不同亚基对动力蛋白马达功能和调节作用的遗传学方法中，我们鉴定出了胞质动力蛋白中间链基因Dic19C中的突变。我们在一项遗传学筛选中使用了功能性Dic转基因，以找回那些需要该转基因才能存活的X连锁致死突变。我们鉴定并表征了三个Dic突变。所有这三个Dic等位基因都会导致幼虫致死，这表明中间链在果蝇中发挥着重要功能。与缺失Dic19C的缺陷类似，Dic突变会显性增强Glued(1)的粗糙眼表型，Glued(1)是动力蛋白激活剂动力蛋白激活复合体p150亚基基因中的一个显性突变。此外，我们通过互补分析确定了一个现有的突变shortwing (sw)是动力蛋白中间链基因的一个等位基因。与新分离出的Dic等位基因不同，shortwing纯合可存活，并且在眼睛和翅膀发育中表现出隐性和温度敏感型缺陷。这些表型可被野生型Dic转基因拯救，这表明shortwing是动力蛋白中间链基因的一个可存活等位基因，并揭示了动力蛋白在翅膀发育过程中的一种新作用。
