Structure and expression of the Drosophila melanogaster gene encoding 6-phosphogluconate dehydrogenase.

We have determined the nucleotide sequence and structure of Pgd+, the Drosophila melanogaster gene that encodes the enzyme, 6-phosphogluconate dehydrogenase (6PGD). The derived 481-amino acid sequence for D. melanogaster 6PGD is presented and compared with 6PGD sequences from other species. To characterize the cis-acting sequences necessary for expression of Pgd+, fragments containing this gene as well as Pgd+ promoter-lacZ fusions were introduced into the D. melanogaster germ line by P-element-mediated transformation. Our results indicate that the large second intron is critical for Pgd+ expression in adults. Only 421 bp of Pgd+ 5'-flanking DNA are necessary to direct expression in imaginal discs, gonads and gut of third-instar larvae. Sequences downstream from the transcription start point are necessary for expression in the larval fat body.