CLONING, SEQUENCING AND EXPRESSION OF AN ISOFORM OF CARDIAC C-PROTEINFROM THE MEXICAN AXOLOTL (AMBYSTOMA-MEXICANUM)

C-protein, a myosin binding protein, is thought to regulate and stabil ize thick filaments during assembly of sarcomeric A-bands. Multiple is oforms of C-protein have been characterized in avian and mammalian sys tems. We now report the isolation and the nucleic acid sequence of a p artial C-protein cDNA clone from an axolotl heart cDNA expression libr ary in lambda gt11. The clone was isolated by screening the library wi th a heterologous monoclonal anti-C-protein antibody (MF1). Sequence c omparison revealed that CPRO(Axocard)1 has an average sequence identit y of 62-68% at the nucleic acid and 72-78% at the amino acid levels re spectively to human and chicken sequences. We could not detect any sig nificant differences at the levels of expression of the cardiac isofor m of C-protein (CPRO(Axocard)1) in normal and non-beating heart tissue s of the double-recessive cardiac lethal mutant (c/c) axolotl, Ambysto ma mexicanum. This is the first report of a C-protein sequence from an amphibian species. (C) 1995 Academic Press, Inc.