Novel rat calpastatin mRNA variants.

Rat calpastatin cDNAs obtained by RT-PCR method were isolated and directly sequenced; this allowed the identification of two new variants both characterized by a 23 amino acids deletion at the end of the unique N-terminal domain L, increasing the number of functional isoforms. The deletion shows high homology to the amino acid sequence coded by exon 8 of human calpastatin gene and properly conserved splicing consensus sequences, suggesting exon skipping in domain L. Furthermore, three point mutations scattered along the coding region were found.