Chromosomal localization of the genes encoding two forms of the G protein beta polypeptide, beta 1 and beta 3, in man.
The signal-transducing G proteins are heterotrimers composed of three subunits, alpha, beta, and gamma. Multiple distinctive forms of the alpha, beta, and gamma subunits, each encoded by a distinct gene, have been described. To investigate further the structural diversity of the beta subunits, we recently cloned and characterized a novel cDNA encoding a third form of the G protein beta subunit, which we have termed beta 3. The protein corresponding to beta 3 has not yet been identified. The three forms of the beta subunit show 81-90% amino acid sequence identity. Previous studies had localized the human genes for the beta 1 and beta 2 subunits to chromosomes 1 and 7, respectively. The present studies were designed to determine whether the gene encoding beta 3 is linked to either the beta 1 or the beta 2 gene. Genomic DNA was isolated from a panel of rodent-human hybrid cell lines and analyzed by hybridization to cDNAs for beta 1 and beta 3. Discordancy analysis allowed assignment of the beta 3 gene to chromosome 12 and confirmed the previous assignment of the beta 1 gene to chromosome 1. These results were confirmed and extended by using in situ chromosome hybridization, which permitted the regional localization of the beta 1 gene to 1pter----p31.2 and the beta 3 gene to 12pter----p12.3. Digestion of human genomic DNA with 10 restriction enzymes failed to disclose a restriction fragment length polymorphism for the beta 3 gene. These data indicate that there is considerable diversity in the genomic organization of the beta subunit family.
Levine
M A
MA
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Modi
W S
WS
O'Brien
S J
SJ
D000818:Animals; D015139:Blotting, Southern; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D002881:Chromosomes, Human, Pair 12; D006224:Cricetinae; D019204:GTP-Binding Proteins / Q000145:classification / Q000235:genetics*; D005796:Genes; D006801:Humans; D006822:Hybrid Cells; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012150:Polymorphism, Restriction Fragment Length; D012689:Sequence Homology, Nucleic Acid
D019204:GTP-Binding Proteins