Conserved structure of regulatory regions of the gap genes giant and Krüppel in Drosophila melanogaster and Rhodnius prolixus.

Conserved structure of regulatory regions of the gap genes giant and Krüppel in Drosophila melanogaster and Rhodnius prolixus. Rolando V. Rivera-Pomar^1,2, Andrés Lavore¹. 1) Centro de Bioinvestigaciones, Univ Nacional del Noroeste de Buenos Aires, Pergamino, Buenos Aires, Argentina; 2) Centro Regional de Estudios Genómicos, Universidad Nacional de La Plata. Florencio Varela, Argentina.

The insects develop in two main ways: short germ band and long germ band embryogenesis. In short germ band insects only the anterior segments are simultaneously specified, while the posterior segments are successively added later on. This mode of development is the most basal and widespread. However, most of our knowledge comes from Drosophila melanogaster, a derived insect with long germ band embryogenesis. Here we analyzed the structure, expression and function of the orthologue genes giant (gt) and Krüppel (Kr) in Rhodnius prolixus, a classical model for insect physiology that is emerging as developmental model due to the sequencing of its genome. Most of the genes that take part of the segmentation process are conserved. We have compared the expression, phenotype and regulatory enhancers of Drosophila, Tribolium and Rhodnius gt and Kr orthologs. By comparative genomic analysis, we have identified a putative regulatory region for Rp-Kr and Tc-Kr using Dm-Kr as a reference. We were able to predict two clusters of binding sites that are coincident with the empirically defined CD1 and CD2 regions. We also show the conservation of putative regulatory regions for Rp-gt. Taken together, the data suggest that the conservation of regulatory regions, at least for gap genes, is not as uncommon as we could have expected for insects largely separated during evolution and with different developmental modes. As the studies of transcriptional regulation in insects are still scarce the data presented here represent a necessary step towards the understanding of the evolution of the segmentation process. This work has been supported by grants from ANPCyT and UNNOBA.