Recent molecular studies have identified the interesting phenomenon of overlapping genes within the 71CD interval of chromosome 3 of Drosophila melanogaster. The overlapping genes exhibit distinct patterns of expression: the E600 gene is blastoderm-stage specific, the overlap (ov1) gene is a germ line expressed gene, and the Eip28/29 gene is ecdysone inducibe. We believe the analysis of these genes will allow us to address several important questions from the standpoint of developmental biology. In this proposal, we focus in on the expression of the ov1 gene. Strategies involving germ line transformation will be used to characterize the cis-acting regulatory elements controlling ov1 gene expression. These experiments should help us to understand the kinds of regulation used in the differential expression of this germ line expressed gene. We will also investigate the potential effect that overlapping gene organization may have on ov1 gene expression. The unusual sequence organization may provide an important regulatory mechanism in the expression of this complex gene cluster. Finally, experiments utilizing in situ hybridization of gene specific probes to RNAs in tissue and animal sections should yield a detailed description of ov1 gene expression during normal development. This is a complex and interesting system of overlapping genes that are apparently under independent control with respect to expression during development, tissue specific expression and hormone dependent expression. Overall, information about this cluster may lead to a better understanding of the processes involved in the regulation of gene expression during cellular differentiation, during gametogenesis and embryogenesis.
