Adh Gene Expression Research Articles

A cytological and molecular analysis of Adh gene expression in Drosophila melanogaster polytene chromosomes

Analysis of puffing patterns in Drosophila melanogaster salivary gland chromosomes indicates the existence of a developmentally specific puff in the 35B region. This puff seems to originate from bands 35B2 or 35B3, where Adh is located, and it is expanded in more than 60% of the nuclei examined. The presence of RNA polymerase II in this puff as well as its ability to incorporate tritiated uridine shows that it corresponds to a transcriptionally active site. RNA blotting and in situ hybridization experiments indicate that Adh is transcribed, although not very actively, in salivary glands during the third larval instar. However, this tissue does not display detectable levels of ADH activity. By contrast, we have found that in midgut polytene chromosomes the 35B region is not visibly puffed in spite of the high levels of Adh transcripts detected. These results seem to suggest that puffing at the 35B region could be mainly promoted by genes closely linked to Adh, possibly with a minor contribution of this gene.

Regulation of expression of Adh genes in maize.

A regulatory mutant of the Adh (alcohol dehydrogenase) gene was induced by ethyl methanesulfonate. The mutation reduces the ability of the gene to complete for the limited gene activating factor. The mutant shows full activity in the homozygote but only one-half the activity of the progenitor gene in heterozygotes where it is competing with another allele for the limited factor. Evidence is presented for multiple regulatory sites in both the Adh and Adh2 loci.