MOLECULAR-CLONING, SEQUENCING AND EXPRESSION OF AN ISOFORM OF CARDIACALPHA-TROPOMYOSIN FROM THE MEXICAN AXOLOTL (AMBYSTOMA-MEXICANUM)

The cDNA for alpha-tropomyosin (TM) was cloned by the polymerase chain reaction (PCR) from a lambda gt11 library constructed with mRNA from juvenile axolotl heart tissues. Subsequently, the nucleotide sequence of the cDNA was determined. This is the first reported cDNA for axolot l alpha-tropomyosin. Comparative analyses of the deduced amino acid se quence of this cDNA with Xenopus skeletal muscle alpha-tropomyosin seq uences indicate that the axolotl heart cDNA has 93% and 96% homology i n the regions of amino acids 39-80 (exon 2b) and 258-284 (exon 9a), re spectively. However, there is about 86.55% homology at the nucleic aci d level (coding region) and 97.5% homology at the amino acid level wit h that of Xenopus skeletal muscle alpha-tropomyosin cDNA. Northern blo t analyses with polyA+ RNA from juvenile heart suggest the presence of at least two different transcripts for alpha-tropomyosin in axolotl h eart. The results of 3'-RACE concur with those of northern blot analys es. (C) 1994 Academic Press, Inc.