Gene interactions in the anterior region of the syncytial blastoderm of Drosophila melanogaster and of the sciarid fly Trichosia pubescens

Abstract

This proposal aims to study gene expression regulation and probe evolutionary mechanisms involved in the segmentation of dipterans. Our main goal is to investigate the transcriptional regulation of the segmentation cascade of Drosophila melanogaster. Our focus is the anterior portion of the syncytial blastoderm of Drosphila where the expression domains of gap genes are partially overlapping. We investigate the hypothesis that this expression pattern underlies a mechanism of combined transcription repression activities that set the borders of anterior pair-rule stripes, as well as the limits among gap domains. Data from literature and unpublished results of our laboratory sustain this hypothesis. We propose genetic crosses, biochemical assays, bioinformatics and computational approaches to check the roles of CG9571 and Tll in this combinatorial system and also, to draw a comprehensive model of the regulation of the combinatorial gap activity operating in the anterior part of the future head region. In parallel, our aim is to identify segmentation orthologous genes in the dipteran Trichosia pubescens and map their expression patterns. These results might reveal a more typical segmentation cascade for dipterans, because the well-studied Drosophila model seems to be not representative for the group according to the literature and preliminary data of our lab. (AU)