cDNA Sequence of human p11 calpactin I light chain

The cDNA encoding full-length human p11 calpactin I light chain has been cloned and subjected to DNA sequencing. The open reading frame specifies a 97-amino-acid residue protein that surprisingly is identical to the p11 sequences of two mammalian ungulate species, cow and pig. However, the previously reported p11 polypeptide sequences of mouse and rat exhibited 8-9% nonidentity to human p11. These mammalian sequence comparison results are unexpected in view of current molecular cladistic theories that suggest a closer relationship between primates and rodents, rather than primates and ungulates. The mouse p11 gene has been previously mapped to chromosome 3 at a position syntenic with a centromeric-proximal region on human chromosome 1, and the human p11 cDNA clone is likely to be useful in physical mapping on chromosome 1.