Abstract
Guanine nucleotide-binding proteins (G proteins) mediate signals between activated cell-surface receptors and cellular effectors. A bovine G-protein alpha-subunit cDNA has been used to isolate similar sequences from Drosophila genomic and cDNA libraries. One class, which we call DG alpha 0, hybridized to position 47A on the second chromosome of Drosophila. The nucleotide sequence of the protein coding region of one cDNA has been determined, revealing an alpha subunit that is 81% identical with rat alpha 0. The cDNA hybridizes strongly to a 3.8 kb mRNA and weakly with a 5.3 kb message. Antibodies raised against a trp-E-DG alpha 0 fusion protein recognized a 39,000 Da protein in Drosophila extracts. In situ hybridization to adult Drosophila sections combined with immunohistochemical studies revealed expression throughout the optic lobes and central brain and in the thoracic and abdominal ganglia. DG alpha 0 message and protein were also detected in the antennae, oocytes, and ovarian nurse cells. The neuronal expression of this gene is similar to mammalian alpha 0, which is most abundantly expressed in the brain.
