Skeletal muscle and brain isoforms of a beta-subunit of human voltage-dependent calcium channels are encoded by a single gene.
Clones of the beta 1-subunit of the voltage-dependent calcium channel (VDCC) from human skeletal muscle and hippocampus cDNA libraries, and from human genomic libraries, were isolated using a human skeletal muscle beta 1 cDNA probe generated by polymerase chain reaction. The skeletal muscle beta 1 cDNA (beta 1M) encodes a protein of 523 amino acids that is 97% identical to the rabbit skeletal muscle beta-subunit. Two different cDNAs, beta 1B1 and beta 1B2, were obtained from the human hippocampus library. The beta 1B1 transcript encodes a protein of 478 amino acids that is identical to the skeletal muscle beta-subunit (beta 1M), except for an internal region of 52 amino acids. The beta 1B2 transcript encodes a protein of 596 amino acids. The beta 1B2 polypeptide is identical to the beta 1B1 polypeptide at amino acids 1-444; however, it has a unique 152 amino acid carboxyl terminus. Like beta 1B1, it differs from beta 1M at the internal 52 amino acids. Analysis of the beta 1 gene structure demonstrates that these three cDNAs represent transcripts encoded by a single beta 1 gene. Transcripts from the beta 1 gene were detected in RNA from skeletal muscle, heart, spleen, and brain, but not in RNA from liver, stomach, or kidney.
Powers
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Department of Anesthesiology, University of Wisconsin, Madison 53705.
Liu
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Hogan
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Gregg
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics*; D003001:Cloning, Molecular; D005796:Genes; D015698:Genomic Library; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009132:Muscles / Q000502:physiology*; D009838:Oligodeoxyribonucleotides; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012326:RNA Splicing; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D015220:Calcium Channels; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D012313:RNA