Spatially restricted expression of pipe in the Drosophila egg chamber defines embryonic dorsal-ventral polarity

The process of dorsal-ventral (DV) polarity in the embryo depends on the expression of pipe in the somatic tissue of the Drosophila ovary. To determine the formation of embryonic DV axis, a candidate pipe locus that encodes an enzyme with similarity to hefaran sulfate 2-0-sulfotransferase and expressed in the ventral follicle cells of the egg chamber was identified. The results of the molecular cloning of this transcription unit and their implications are discussed.