Alternative splicing produces transcripts encoding two forms of the α subunit of GTP-binding protein G_o

The α subunit of the guanine nucleotide-binding protein G_o ("o" for other) is believed to mediate signal transduction between a variety of receptors and effectors. cDNA clones encoding two forms of G_o α subunit were isolated from a mouse brain library. These two forms, which we call G_oAα and G_oBα, appear to be the products of alternative splicing. G_oAα differs from G_oBα over the C-terminal third of the deduced protein sequence. Both forms are predicted to be substrates for ADP-ribosylation by pertussis toxin. G_oAα transcripts are present in a variety of tissues but are most abundant in brain. The G_oBα transcript is expressed at highest levels in brain and testis. It is possible that G_oAα and G_oBα have different functions.