Cloning and sequencing of a rat heart cDNA encoding a G-protein beta subunit related to the human retinal beta 3...

A cDNA (pJ5) encoding a protein with significant sequence identity to the previously known beta 1, beta 2, beta 3 and beta 4 subunits of guanine-nucleotide-binding proteins (G proteins) has been cloned from a 8-12-week-old rat heart cDNA library. Its predicted amino acid (aa) sequence of 340 aa most closely resembles that of the human beta 3 subunit, showing 96% identity. Northern blot analysis revealed that the major mRNA corresponding to the rat pJ5 cDNA is 2.0 kb in length. It is expressed at a high level in the heart and at a much lower level in the brain.