MOLECULAR-CLONING OF HUMAN G-ALPHA(Q) CDNA AND CHROMOSOMAL LOCALIZATION OF THE G-ALPHA(Q) GENE (GNAQ) AND A PROCESSED PSEUDOGENE

G alpha(q) is the alpha subunit of one of the heterotrimeric GTP-bindi ng proteins that mediates stimulation of phospholipase C beta. We repo rt the isolation and characterization of cDNA clones from a frontal co rtex cDNA library encoding human G alpha(q) The encoded protein is 359 amino acids long and is identical in all but one amino acid residue t o mouse G alpha(q). Analysis of human genomic DNA reveals an intronles s sequence with strong homology to human G alpha(q) cDNA. In compariso n to G alpha(q) cDNA, this genomic DNA sequence includes several small deletions and insertions that alter the reading frame, multiple singl e base changes, and a premature termination codon in the open reading frame, hallmarks of a processed pseudogene, Probes derived from human G alpha(q) cDNA sequence map to both chromosomes 2 and 9 in high strin gency genomic blot analyses of DNA from a panel of human-rodent hybrid cell Lines. PCR primers that selectively amplify the pseudogene seque nce generate a product only when DNA containing human chromosome 2 is used as the template, indicating that the authentic G alpha(q) gene (G NAQ) is located on chromosome 9. Regional localization by FISH analysi s places GNAQ at 9q21 and the pseudogene at 2q14.3-q21.