Investigating the segmentation cascade in the anterior regions of the embryo of Drosophila melanogaster and of the sciarid Trichosia pubescens

Abstract

The aim of this proposal is to study the molecular aspects of the segmentation cascade in the anterior regions of the embryos of two species of dipterans, the Drosophila melanogster model and the sciarid fly Trichosia pubescens. For Drosophila, we aim to investigate the transcriptional regulation of the modular promoters of the pair-rule genes. In the anterior regions of Drosophila, corresponding to the future head, the segmentation was poorly investigated and its functioning poorly known in relation to other parts of the embryo. We are working with the hypothesis that in the anterior regions of the embryo, there is a complex regulatory network controlling the correct positioning of the expression of pair-rule gene stripes. To investigate this hypothesis we propose experiments to identify the components and the underlying mechanisms involved in this regulation. In parallel we aim to study the segmentation in the sciarid fly Trichosia pubescens. Molecular aspects of the segmentation were investigated for just a couple of species, however, the evidence already obtained point to differences in critical aspects between the functioning of the cascade in the anterior regions of the Drosophila embryo and in other insects or even in other dipterans. With the experiments of cloning and determination of gene expression patterns outlined here, we intend to reveal molecular aspects of the segmentation of this species and to contribute to better understanding the evolutionary process of the segmentation among the dipterans. (AU)