Two independent cis-acting elements regulate the sex- and tissue-specific expression ofyp3inDrosophila melanogaster

SummaryInDrosophila, the threeyolk protein(yp) genes are transcribed in a sex-, tissue- and developmentally specific manner, providing an ideal system in which to investigate the factors involved in their regulation. The yolk proteins are synthesized in the fat body of adult females, and in the ovarian follicle cells surrounding the developing oocyte during stages 8–10 of oogenesis. We report here an analysis of theyolk protein 3(yp3) gene and its flanking sequences by means of P-element mediated germ-line transformation and demonstrate that a 747 bp promoter region is sufficient to direct sex-specific expression in the female fat body and both the temporal- and cell-type-specificity of expression during oogenesis. Two elements that independently governyp3transcription in these tissues have been separated and no other sequences in the upstream, downstream or coding regions have been identified that are autonomously involved inyp3expression.