title: Characterization of a mammalian smooth muscle myosin heavy-chain gene: complete nucleotide and protein coding sequence and analysis of the 5' end of the gene.
abstract: The purpose of this study was to characterize the complete cDNA sequence encoding the rabbit smooth muscle myosin heavy chain (MHC) and determine the exon/intron organization at the 5' end of the corresponding gene. The full-length cDNA sequence of 6644 base pairs encoding a protein of 1972 amino acids was generated from two cDNA clones: PBRUC1 (approximately 6.3 kilobases), isolated from a rabbit uterus cDNA library, and PBRU-PCR33 (420 base pairs), produced by primer extension and PCR amplification. Compared with the chicken smooth muscle MHC sequence [Yanagisawa, M., Hamada, Y., Katsuragawa, Y., Imamura, M., Mikawa, T. & Masaki, T. (1987) J. Mol. Biol. 198, 143-157] the rabbit MHC shares about 90% amino acid identity in the S1 globular head region but shows a striking sequence divergence at the junction between the 25-kDa and 50-kDa proteolytic fragments of the functionally important S1 head domain. Genomic cloning shows that the rabbit smooth muscle MHC gene is large and has an unusual exon/intron organization at the 5' end. The first eight contiguous exons are located within a region of at least 70 kilobases of genomic DNA. Some introns span several kilobases of DNA and others at the 5' end show a high degree of intron conservation in the Mg(2+)-ATPase domain when compared with more distantly related sarcomeric MHC genes. Primer extension and S1 nuclease mapping analysis demonstrate that transcription initiates from a single site in the rabbit smooth muscle MHC gene.
authors.affiliation: Department of Physiology and Biophysics, University of Vermont College of Medicine, Burlington 05405.
authors.forename: P
authors.initials: P
authors.lastname: Babij
authors.forename: C
authors.initials: C
authors.lastname: Kelly
authors.forename: M
authors.initials: M
authors.lastname: Periasamy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005260:Female; D015723:Gene Library; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000502:physiology*; D009218:Myosins / Q000235:genetics*; D009838:Oligodeoxyribonucleotides; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D011817:Rabbits; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014599:Uterus / Q000502:physiology*
chemical_list: D009838:Oligodeoxyribonucleotides; D004247:DNA; D009218:Myosins