title: A cluster of three novel Ca2+ channel gamma subunit genes on chromosome 19q13.4: evolution and expression profile of the gamma subunit gene family.
abstract: The CACNG1 gene on chromosome 17q24 encodes an integral membrane protein that was originally isolated as the regulatory gamma subunit of voltage-dependent Ca2+ channels from skeletal muscle. The existence of an extended family of gamma subunits was subsequently demonstrated upon identification of CACNG2 (22q13), CACNG3 (16p12-p13), and CACNG4 and CACNG5 (17q24). In this study, we describe a cluster of three novel gamma subunit genes, CACNG6, CACNG7, and CACNG8, located in a tandem array on 19q13.4. Phylogenetic analysis indicates that this array is paralogous to the cluster containing CACNG1, CACNG5, and CACNG4, respectively, on chromosome 17q24. We developed sensitive RT-PCR assays and examined the expression profile of each member of the gamma subunit gene family, CACNG1-CACNG8. Analysis of 24 human tissues plus 3 dissected brain regions revealed that CACNG1 through CACNG8 are all coexpressed in fetal and adult brain and differentially transcribed among a wide variety of other tissues. The expression of distinct complements of gamma subunit isoforms in different cell types may be an important mechanism for regulating Ca2+ channel function.
authors.affiliation: Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA. dburgess@bcm.tmc.edu
authors.forename: D L
authors.initials: DL
authors.lastname: Burgess
authors.forename: L A
authors.initials: LA
authors.lastname: Gefrides
authors.forename: P J
authors.initials: PJ
authors.lastname: Foreman
authors.forename: J L
authors.initials: JL
authors.lastname: Noebels
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001921:Brain / Q000196:embryology / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics*; D002460:Cell Line; D002531:Cerebellum / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism; D002888:Chromosomes, Human, Pair 19; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D016678:Genome; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D018482:Muscle, Skeletal / Q000378:metabolism; D010802:Phylogeny; D020033:Protein Isoforms; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic
chemical_list: D015220:Calcium Channels; D020033:Protein Isoforms