The Drosophila G protein gamma subunit gene (D-G gamma 1) produces three developmentally regulated transcripts and is predominantly expressed in the central nervous system.
A genomic clone, 536, located at the 44CD region of polytene chromosomes of Drosophila melanogaster, has been characterized for its neurobiological importance. We found that this clone contains a gene which produces 2.6-, 1.3- and 1.1-kilobase (kb) RNAs. While the 2.6-kb RNA is expressed only in the head, the 1.3-kb RNA is present exclusively in the body. The 1.1-kb RNA, however, is found in both the head and body, but in much higher concentration in the head. DNA sequence analysis of a 2.6-kb RNA-specific cDNA showed that this gene encodes a 70-amino acid polypeptide which is the putative Drosophila homologue to the gamma subunit of the bovine G-protein. The Drosophila protein, named D-G gamma 1, shares 46, 43, and 28% identity, and 59, 52, and 60% similarity, with the gamma 2, gamma 3, and gamma t proteins of bovine G proteins, respectively. Sequencing of the 1.1-kb RNA-specific cDNA clone revealed that the 1.1-kb RNA is produced from the 2.6-kb transcription unit by usage of an alternative polyadenylation site, and has a coding region identical to that of the 2.6-kb RNA. Genomic Southern blot hybridization indicated that the Drosophila genome has only one D-G gamma 1 gene. Throughout development the 1.1-kb RNA is found to be the most prevalent species; its level peaks between 9 and 12 h of embryogenesis. As is the case for the other G protein genes of Drosophila, the D-G gamma 1 gene is predominantly expressed in the central nervous system of the fly.
Ray
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Department of Zoology, University of Tennessee, Knoxville 37996.
Ganguly
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002417:Cattle; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development; D019204:GTP-Binding Proteins / Q000235:genetics*; D015870:Gene Expression; D005796:Genes; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009424:Nervous System Physiological Phenomena; D016366:Open Reading Frames; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D012313:RNA; D004247:DNA; D019204:GTP-Binding Proteins