In vivo transcriptional analysis of the TATA-less promoter of the Drosophila melanogaster vermilion gene.

Transcriptional regulation of the TATA-less promoter of the Drosophila melanogaster vermilion (v) gene was investigated. Developmental Northern (RNA) blot analysis showed that v transcripts accumulate during late embryo, larval, and adult stages. Sequences that control expression in adults were delineated by analyzing a series of 5' and 3' deletion constructions after germ line transformation. These studies defined two regions, -300 to -600 and -60 to -160, relative to the major transcription start site, as important for maximal levels of expression. Analysis of transformants bearing v-lacZ promoter fusions showed that larval expression is fat body specific and that expression depends on sequences located between +19 and +36 downstream of transcription start site. This downstream element can be functionally replaced by a TATA box in vivo. Furthermore, when added to the wild-type v promoter, a TATA element augments the level of v transcription by three- to fivefold.