Hauck B, Gehring W J, Walldorf U
Institut für Allgemeine Genetik (240), Universität Hohenheim, Garbenstrasse 30, D-70593 Stuttgart, Germany.
Proc Natl Acad Sci U S A. 1999 Jan 19;96(2):564-9. doi: 10.1073/pnas.96.2.564.
The development of the Drosophila compound eye requires the function of a set of evolutionarily conserved genes. Among these, the Drosophila Pax-6 gene eyeless (ey) plays a major role. ey has been considered a master control gene of eye development in the animal kingdom because targeted expression of ey and vertebrate as well as invertebrate homologs lead to the formation of ectopic eyes in Drosophila. We demonstrate that an intron of the ey gene contains an enhancer that regulates the eye specific expression of the gene in the eye disc primordia of embryos and in the eye imaginal discs of third instar larvae. Moreover, a 212-bp enhancer element is necessary and sufficient for the enhancer function. It is partially conserved in Drosophila hydei and contains putative Pax-6 Paired domain binding sites. We show that several binding sites are required for the eye specific expression, and, therefore, we propose a Pax-6-like molecule to be a positive transactivator for the eye specific ey expression. This transactivator recently has been identified as twin of eyeless, the second Pax-6 gene in Drosophila.
果蝇复眼的发育需要一组进化上保守的基因发挥作用。其中，果蝇的Pax-6基因无眼（ey）起着主要作用。ey被认为是动物界眼睛发育的主控基因，因为ey以及脊椎动物和无脊椎动物同源物的靶向表达会导致果蝇中异位眼的形成。我们证明，ey基因的一个内含子包含一个增强子，该增强子在胚胎的眼盘原基和三龄幼虫的眼成虫盘中调节该基因的眼特异性表达。此外，一个212 bp的增强子元件对于增强子功能是必需且足够的。它在海德氏果蝇中部分保守，并包含假定的Pax-6配对结构域结合位点。我们表明，几个结合位点对于眼特异性表达是必需的，因此，我们提出一种类似Pax-6的分子是眼特异性ey表达的正性反式激活因子。这种反式激活因子最近被鉴定为无眼双基因，即果蝇中的第二个Pax-6基因。
