TRANSCRIPTIONAL ACTIVATION OF THE DROSOPHILA-MELANOGASTER GLUCOSE-6-PHOSPHATE-DEHYDROGENASE GENE BY INSERTION OF DEFECTIVE P-ELEMENTS

Tandem insertions of defective P elements (1.15 kb KP and 0.6 kb core P) accelerate the transcription rate of the glucose-6-phosphate dehydr ogenase (G6PD) gene in Drosophila melanogaster. In this report, we hav e analyzed the activation mechanism of the G6PD promoter by in vitro t ranscription and gel retardation assays. Results showed that one cis-a cting region in the core P and. two such regions in the KP are associa ted with activation of the G6PD promoter, and that putative transcript ional regulatory protein(s) which specifically bind to each of the cis -acting regions are present in nuclear extracts of Canton S embryos. O n the other hand, the P elements do not activate the normal actin 5C p romoter, but activate the promoter when the 20 bp sequence around the G6PD transcription start site is placed in front of the promoter. It a ppears that the GC-rich region in this 20 bp sequence is required for the activation.