Edgar B A, O'Farrell P H
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Cell. 1990 Aug 10;62(3):469-80. doi: 10.1016/0092-8674(90)90012-4.
The string (stg) locus of Drosophila encodes a factor that is thought to trigger mitosis by activating the p34cdc2 protein kinase. stg is required for mitosis early in development and is transcribed in a dynamic pattern that anticipates the pattern of embryonic cell divisions. Here we show that differential cell cycle regulation during postblastoderm development (cell cycles 14-16) occurs in G2. We demonstrate that stg mRNA expressed from a heat shock promotor triggers mitosis, and an associated S phase, in G2 cells during these cycles. Hence, differential cell cycle timing at this developmental stage is controlled by stg. Finally, we use heat-induced stg expression to alter the normal pattern of embryonic mitoses. Surprisingly, the complex mitotic pattern evident during normal development is not essential for many features of pattern formation or for viability.
果蝇的string（stg）基因座编码一种因子，该因子被认为通过激活p34cdc2蛋白激酶来触发有丝分裂。stg在发育早期的有丝分裂中是必需的，并且以一种动态模式进行转录，这种模式预示着胚胎细胞分裂的模式。在这里，我们表明在胚盘后期发育（细胞周期14 - 16）期间，不同的细胞周期调控发生在G2期。我们证明，从热休克启动子表达的stg mRNA在这些周期的G2细胞中触发有丝分裂以及相关的S期。因此，在这个发育阶段不同的细胞周期时间是由stg控制的。最后，我们利用热诱导的stg表达来改变胚胎有丝分裂的正常模式。令人惊讶的是，正常发育过程中明显的复杂有丝分裂模式对于模式形成的许多特征或生存能力并非必不可少。
