The chorion genes of Drosophila melanogaster are expressed in distinct spatial and temporal patterns in female follicles (eggchambers) and provide a powerful system for molecular analysis of developmental gene expression. To dissect the molecular mechanisms governing spatial expression, the PI has identified and cloned CF4: a DNA-binding protein which interacts with sequences of the s36 chorion gene. CF4 contains a novel DNA-binding domain. The PI will focus on the molecular biology and developmental genetics of CF4 to confirm its involvement in regional-specific chorion gene expression by: examining the temporal and spatial RNA and protein distribution of CF4 in follicles, initiating molecular and biochemical studies, and using a genetic approach for identifying existing or generating new mutations using the FLP recombination system to generate genetic mosaic follicles, and he will also develop a GALA directed follicle-specific gain of function assay and examine the effect of CF4 ectopic expression.//