Characterization of the G protein 73 Subunit Gene Reveals a Novel Gene

Heterotrimeric G proteins, composed of an α, β, and γ subunit, play a central role in cell function by transducing signals from transmembrane receptors to intracellular effectors. Since the nervous system exhibits a wealth of G protein mediated signaling pathways, we have begun characterization of the 7 subunit family by isolating and characterizing those genes which encode 7 subunits enriched within the nervous system. We have isolated the mouse 78 gene, determined its exon-intron distribution, and analyzed the 5' flanking region. Within ihe 5' flanking region of the 78 gene we identified a novel gene of unknown function, termed the 73 linked gene (3lg}. Sequence analysis, RT-PCR, primer extension analysis, and RNase protection assays indicate that 78 and Slg are transcribed in opposite directions, oriented in a head-to-head manner, and are separated by less than 50 bp. Slg is transcriptionally regulated in a manner similar to 78- Consistent with this gene organization; the UniGene database indicates that both 78 and Slg are closely linked within the human genome as well. The mechanisms underlying the transcriptional regulation of these two genes is of considerable interest.