Hama C, Ali Z, Kornberg T B
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Genes Dev. 1990 Jul;4(7):1079-93. doi: 10.1101/gad.4.7.1079.
The Drosophila engrailed gene is expressed in the cells of the posterior developmental compartments. To investigate how the engrailed gene is regulated, chimeric genes consisting of fragments of the engrailed promoter and Escherichia coli lacZ were incorporated into the Drosophila germ line by P-element-mediated recombination. Fusion constructs with 7.5 kb of 5'-flanking sequence contain sufficient information to promote expression in most of the embryonic, larval, and imaginal posterior compartments; transformants with smaller fragments of the 5' region do not. Remarkably, of 20 independent transformants with constructs containing more than 1 kb of 5'-flanking DNA, 7 integrated in or around the engrailed locus. These strains inactivate engrailed function to varying degrees, and some express lacZ with a position- and temporal-specific program that is indistinguishable from the normal engrailed gene. Presumably, in these strains, lacZ is expressed in the context of the engrailed promoter.
果蝇的engrailed基因在发育中后部区域的细胞中表达。为了研究engrailed基因是如何被调控的，通过P因子介导的重组将由engrailed启动子片段和大肠杆菌lacZ组成的嵌合基因导入果蝇种系。含有7.5 kb 5'侧翼序列的融合构建体包含足够的信息，可促进在大多数胚胎、幼虫和成虫后部区域的表达；而含有5'区域较小片段的转化体则不能。值得注意的是，在20个含有超过1 kb 5'侧翼DNA构建体的独立转化体中，有7个整合到engrailed基因座内或其周围。这些品系在不同程度上使engrailed功能失活，并且一些品系以与正常engrailed基因无法区分的位置和时间特异性模式表达lacZ。据推测，在这些品系中，lacZ是在engrailed启动子的背景下表达的。
