Molecular cloning of bovine actin-like protein, actin2.

Actins are major cytoskeletal components and highly conserved in evolution. In mammals, there are six actin isoforms, a pair of which shows at least 93% identity in the amino acid sequence. We have cloned cDNA for a bovine protein that is distantly related to members of the mammalian actin isotypes. The predicted amino acid sequence (418 residues long, calculated molecular mass 47369) shows that this protein, which we have named actin2, exhibits 36% identity to mammalian actins and 60% identity to the yeast actin-like protein, act2. We have concluded that actin2 defines a new class of mammalian actin-like proteins. It was also revealed that actin2 messenger RNA is expressed in a broad range of tissues.