Differential expression of novel gsα signal transduction protein cDNA species

Abstract

The Gsα guanine nucleotide-binding signal transduction protein is part of a heterotrimeric complex that is involved in the stimulation of adenylate cyclase upon activation of membrane receptors. We report the characterization of 16 Gsα cDNA clones isolated from the human adult retina and fetal eye libraries. Molecular heterogeneity in the 5'- region defines four novel Gsα cDNA species which are generated either by alternate splicing or by using alternative promoter. The novel exons upstream of exon 2 interrupt the highly conserved 'region A' in the Gsα polypeptide. Non-AUG codons in the novel 5'-exon can initiate translation of these Gsα species in vitro. Reverse transcription of total RNA coupled with polymerase chain reaction (RTPCR) using specific primers and in situ hybridization to mRNA in baboon tissue sections with a specific oligonucleotide probe show a high level of expression of these species in retina and brain but not in liver. Differential expression of alternatively spliced Gsα species suggests novel signal transducing pathways. © 1991 Oxford University Press.