CIS-ACTING SEQUENCES CONTROLLING THE ADULT-SPECIFIC TRANSCRIPTION PATTERN OF THE DROSOPHILA-AFFINIDISJUNCTA ADH GENE

The cis-acting sequences required for the adult-specific expression pa ttern of the alcohol dehydrogenase (Adh) gene of the Hawaiian picture- winged fruit fly, Drosophila affinidisjuncta were analyzed by germline transformation. Normally this gene produces two developmentally regul ated transcripts. The upstream (distal) promoter produces a distal tra nscript, which makes up about 80% of the total in adults, while the do wnstream (proximal) promoter produces a corresponding proximal transcr ipt, which accounts for the remainder. Previously constructed genes la cking regions corresponding to regulatory elements within the Drosophi la melanogaster Adh gene or regions known to be required for full expr ession of the D. affinidisjuncta Adh gene in larvae were analyzed by i ntroduction into the germline of D. melanogaster followed by RNase-pro tection analysis of RNA levels. In addition, to test a model of prefer ential promoter utilization by which transcription at the proximal pro moter is inhibited by transcription initiated at the upstream distal p romoter, a construction lacking the distal promoter was analyzed. Sequ ences homologous to the adult enhancer of the Adh gene of D. melanogas ter appear to play a similar role in the D. affinidisjuncta gene. In c ontrast to what has been reported for other Drosophila Adh genes, this and some other regulatory elements are shared by the two promoters of the D. affinidisjuncta gene. Taken together, the results favor a mode l of stage-specific switching between the two promoters of the D. affi nidisjuncta gene that involves competition for limiting components sti mulating transcription, rather than interference by read-through from the upstream promoter. Dev. Genet. 23:119-127, 1998. (C) 1998 Wiley-Li ss, Inc.