NSF Award
0110856
0110856<br/>Jaynes<br/><br/>This proposal is to investigate two aspects of transcriptional<br/>regulation in developing Drosophila embryos. The first is a novel<br/>long-range activity that occurs at the even-skipped (eve) locus at the<br/>blastoderm stage of development, earlier than similar long-range activities<br/>are thought to be active at other genes. The second is the mechanism of<br/>repression by the eve protein product, Eve.<br/><br/>Long-range regulation is thought to underlie such phenomena as<br/>epigenetic control of gene expression. Epigenetic mechanisms are known to<br/>be important for maintaining the correct spatial domains of expression of<br/>HOX and other genes, mediated by genes of the Polycomb and trithorax<br/>groups. This and other epigenetic phenomena, such as position effect<br/>variegation and repression at the mating type locus in yeast, are mediated<br/>in part by the regulation of chromatin structure. In contrast to the<br/>well-studied examples of these phenomena in Drosophila, long-range<br/>regulation at eve occurs at very early stages of development, so that its<br/>analysis may provide a novel perspective on the mechanisms involved. This<br/>proposal uses an integrated biochemical and genetic approach to investigate<br/>these mechanisms, to identify specific DNA sequences that mediate the<br/>effects, to identify and study the functions of proteins that bind to those<br/>sequences, and to identify genes that contribute to long-range regulation<br/>of eve.<br/><br/>Transcriptional repression is a crucial activity in the function of<br/>many DNA binding proteins. Through work on this project, Eve has been<br/>shown to interact functionally with the corepressor Groucho. Eve has also<br/>been shown to contain a Groucho-independent repression activity. This<br/>proposal will investigate the mechanisms of each of these activities using<br/>a genetic approach. Fusion proteins between Eve repression domains and the Gal4 DNA binding protein repress reporter transgenes both early and late in embryonic development, providing an efficient means of screening for<br/>genetic modifiers of this repression activity. This proposal will screen<br/>simultaneously for modifiers of Groucho-dependent and -independent<br/>repression activity. This work should provide novel insights into the<br/>mechanisms of repression.
