Manoukian A S, Krause H M
Banting and Best Department of Medical Research, University of Toronto, C.H. Best Institute, Ontario, Canada.
Genes Dev. 1992 Sep;6(9):1740-51. doi: 10.1101/gad.6.9.1740.
The Drosophila pair-rule gene even-skipped (eve) encodes a homeo-domain-containing protein (Eve) that is required for the development of both odd- and even-numbered parasegments. We have used a heat shock-inducible eve transgene to study the regulatory functions of Eve in vivo. Transcripts encoded by eight other segmentation genes were monitored for changes in distribution and abundance following short pulses of ectopic Eve expression. Two tiers of response times appeared to distinguish between genes that were direct [fushi tarazu (ftz), odd-skipped (odd), runt (run), paired, and wingless] and indirect [eve, hairy, and engrailed (en)] targets of Eve. Genes that appeared to be directly regulated by Eve were differentially repressed in a concentration-dependent fashion. Interestingly, the run and ftz genes could also be activated by Eve during a brief 20- to 30-min stage in development. The delayed actions upon the eve and en genes appeared to be mediated by run and odd. As in eve- embryos, these effects on segmentation gene expression patterns caused defects in both odd- and even-numbered parasegments. Four sequential phenotypes could be induced, each of which was attributable to the altered expression of a unique subset of target genes.
果蝇体节极性基因“偶数缺失”（eve）编码一种含同源结构域的蛋白质（Eve），该蛋白质对于奇数和偶数副节的发育都是必需的。我们利用热休克诱导型eve转基因来研究Eve在体内的调控功能。在短暂异位表达Eve后，监测由其他八个体节基因编码的转录本在分布和丰度上的变化。似乎有两层反应时间区分了Eve的直接靶标基因[分节基因（ftz）、奇数缺失（odd）、 runt（run）、配对（paired）和无翅（wingless）]和间接靶标基因[eve、毛状（hairy）和 engrailed（en）]。似乎受Eve直接调控的基因以浓度依赖的方式受到不同程度的抑制。有趣的是，在发育过程中一个短暂的20到30分钟阶段，run和ftz基因也能被Eve激活。对eve和en基因的延迟作用似乎是由run和odd介导的。与eve突变体胚胎一样，这些对体节基因表达模式的影响在奇数和偶数副节中都导致了缺陷。可以诱导出四种连续的表型，每种表型都归因于靶基因独特子集的表达改变。
