Kuziora M A, McGinnis W
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511.
Cell. 1988 Nov 4;55(3):477-85. doi: 10.1016/0092-8674(88)90034-7.
The Deformed (Dfd) gene is a homeotic selector that functions in specifying the identity of the mandibular and maxillary segments. We have constructed transformed fly strains carrying a Dfd cDNA under the heat-inducible control of the hsp70 promoter. With these strains we can induce the ectopic expression of Dfd protein in other segments at various stages of embryonic development. We find that both early and persistent synthesis of the protein is required for the transformation of other body segments toward head segmental identity. The persistent expression of the Dfd protein requires an endogenous copy of the Dfd gene, and we show that the expression of the endogenous copy can be induced by hsDfd expression. This implies that the Dfd protein autoactivates expression from the Dfd locus during normal development. The autoactivation circuit supplies a simple mechanism that can account, in part, for the stability of the determined state controlled by Dfd.
畸形（Dfd）基因是一种同源异型选择基因，在确定下颌和上颌节段的身份中发挥作用。我们构建了在热休克蛋白70（hsp70）启动子的热诱导控制下携带Dfd互补DNA（cDNA）的转基因果蝇品系。利用这些品系，我们可以在胚胎发育的各个阶段诱导Dfd蛋白在其他节段中异位表达。我们发现，蛋白质的早期合成和持续合成对于其他身体节段向头部节段身份的转变都是必需的。Dfd蛋白的持续表达需要Dfd基因的内源拷贝，并且我们表明内源拷贝的表达可以由hsDfd表达诱导。这意味着Dfd蛋白在正常发育过程中从Dfd基因座自动激活表达。自动激活回路提供了一种简单的机制，该机制可以部分解释由Dfd控制的确定状态的稳定性。
