Murata T, Kageyama Y, Hirose S, Ueda H
Department of Genetics, The Graduate University for Advanced Studies, National Institute of Genetics, Shizuoka-ken, Japan.
Mol Cell Biol. 1996 Nov;16(11):6509-15. doi: 10.1128/MCB.16.11.6509.
The transcription factor FTZ-F1 is a member of the nuclear hormone receptor superfamily and is transiently expressed during the mid- and late prepupal periods in Drosophila melanogaster. A putative pupal cuticle gene, EDG84A, is expressed slightly following FTZ-F1 expression during the prepupal period and carries a strong FTZ-F1 binding site between bases 100 and 92 upstream of its transcription start site. In this study, EDG84A mRNA was found to be prematurely expressed upon heat induction of FTZ-F1 in prepupae carrying the heat shock promoter-FTZ-F1 cDNA fusion gene construct. Transgenic fly lines having the 0.8-kb region of the EDG84A promoter fused to lacZ expressed the reporter gene in a tissue- and stage-specific manner. Base substitutions in the FTZ-F1 binding site within the 0.8-kb promoter abolished expression of lacZ. These results strongly suggest that the EDG84A gene is a direct target of FTZ-F1. Deletion studies of the cis-regulatory region of the EDG84A gene revealed that space-specific expression in imaginal disc-derived epidermis is controlled by the region between bp -408 and -104 from the transcription start site. The region between bp -408 and -194 is necessary to repress expression in a posterior part of the body, while the region between bp -193 and -104 carries a positive element for activation in an anterior part of the body. These results suggest that FTZ-F1 governs expression of the EDG84A gene in conjunction with putative tissue-specific regulators.
转录因子FTZ-F1是核激素受体超家族的成员，在黑腹果蝇蛹前期和蛹后期短暂表达。一个假定的蛹表皮基因EDG84A，在蛹前期FTZ-F1表达后略有表达，并且在其转录起始位点上游100至92碱基之间带有一个强FTZ-F1结合位点。在本研究中，发现在携带热休克启动子-FTZ-F1 cDNA融合基因构建体的蛹中，热诱导FTZ-F1时EDG84A mRNA会过早表达。将EDG84A启动子的0.8 kb区域与lacZ融合的转基因果蝇品系以组织和阶段特异性方式表达报告基因。0.8 kb启动子内FTZ-F1结合位点的碱基替换消除了lacZ的表达。这些结果有力地表明EDG84A基因是FTZ-F1的直接靶标。对EDG84A基因顺式调控区的缺失研究表明，成虫盘衍生表皮中的空间特异性表达受转录起始位点-408至-104碱基之间区域的控制。-408至-194碱基之间的区域对于抑制身体后部的表达是必需的，而-193至-104碱基之间区域带有一个在身体前部激活的正调控元件。这些结果表明FTZ-F1与假定的组织特异性调节因子共同调控EDG84A基因的表达。
