Molecular localization, developmental expression and nucleotide sequence of the alpha-methyldopa hypersensitive gene of Drosophila.

The region surrounding the dopa decarboxylase gene of Drosophila contains a cluster of functionally related genes, many of which affect cuticle development and/or catecholamine metabolism. In this report we describe the molecular mapping and sequencing of a full-length cDNA copy of a transcript that maps to the alpha-methyldopa hypersensitive region. Developmental RNA blots show stage-specific patterns of transcription and multiple RNA transcripts. A 2-kb transcript is most abundant at about 12 hr of embryogenesis, and lower levels are detected throughout most of embryogenesis. Lower levels of this transcript are also detected in adults. Smaller stage-specific transcripts are detected in late third-instar larvae. This pattern of transcription is consistent with the known lethal phases and phenotypes of the alpha-methyldopa hypersensitive gene (amd). Based on map position, pattern of transcription, homology with dopa decarboxylase and association with altered DNA in mutants, we conclude that this transcript represents the amd gene.