The complete sequence and expression patterns of the atrial myosin heavy chain in the developing chick

We have earlier reported partial cloning of a cDNA of a chick atrial myosin heavy chain (MHC) gene, CCSV2 and its expression pattern in embryonic chic k hearts (Oana et al (1995) fur J Cell Biol 67, 42-49). In this study, five overlapping cDNA clones (including CCSV2) which together encode the entire open reading frame of the chick atrial MHC gene were characterized, and bo th the entire nucleotide sequence consisting of 5825 bases and the deduced amino acid sequence consisting of 1931 amino acids determined. Reinvestigat ion of the nucleotide sequence of the previously reported and presumably di fferent chick atrial specific MHC cDNA clone, AMHC1 (Yutzey et al (1994) De velopment 120, 871-883), revealed that our clone and AMHC1 encoded the same MHC. The chick atrial MHC gene was strongly expressed in developing chick atria from a very early stage (Hamburger and Hamilton stage 9, 29-33 h) to the adult stage. This gene was also expressed, although weakly, in the vent ricle, somite (the precursor to skeletal muscle) and skeletal muscle during embryonic stages but not in adults. ((C) Elsevier, Paris).