Doyle H J, Kraut R, Levine M
Department of Biological Sciences, Columbia University, New York, New York 10027.
Genes Dev. 1989 Oct;3(10):1518-33. doi: 10.1101/gad.3.10.1518.
zerknüllt (zen) is one of approximately 10 zygotically active genes that control the differentiation of the dorsal-ventral (D/V) pattern during early embryogenesis in Drosophila. Past genetic analyses suggest that maternal factors repress the expression of zen in ventral regions, thereby restricting zen products to dorsal and dorsal-lateral regions of precellular embryos. Subsequent interactions with other zygotic D/V regulatory genes refine the zen pattern, restricting expression to the dorsal-most ectoderm. Here we describe the use of zen promoter fusions and P-element transformation to identify cis elements that are responsible for the complex spatial pattern of zen expression. The zen promoter shows a two-tier organization: Distal sequences mediate its initial response to maternal factors, whereas proximal sequences are responsible for the refinement of the pattern in older embryos. The distal regulatory element has the property of a silencer (or anti-enhancer) element and can act over a distance to repress ventral expression of a heterologous promoter. Also, we discuss evidence that proximal promoter sequences interact with factors that may be modulated by a cell-cell communication pathway.
“皱缩”（zen）是大约10个合子激活基因之一，这些基因在果蝇早期胚胎发育过程中控制背腹（D/V）模式的分化。过去的遗传分析表明，母体因子抑制zen在腹侧区域的表达，从而将zen产物限制在前细胞胚胎的背侧和背外侧区域。随后与其他合子D/V调节基因的相互作用完善了zen模式，将表达限制在最背侧的外胚层。在这里，我们描述了使用zen启动子融合和P元素转化来鉴定负责zen表达复杂空间模式的顺式元件。zen启动子呈现出两层组织：远端序列介导其对母体因子的初始反应，而近端序列负责在较老胚胎中完善模式。远端调节元件具有沉默子（或抗增强子）元件的特性，并且可以在一定距离内起作用以抑制异源启动子的腹侧表达。此外，我们讨论了近端启动子序列与可能由细胞间通讯途径调节的因子相互作用的证据。
