Four synonymous genes encode calmodulin in the teleost fish, medaka (Oryzias latipes): conservation of the multigene one-protein principle.

We cloned four distinct calmodulin (CaM)-encoding cDNAs from a small teleost fish, medaka (Oryzias latipes). The deduced amino acid (aa) sequences were exactly the same in these four genes and identical to the aa sequence of mammalian CaM, because of synonymous codon usages. The four cDNAs from medaka, termed CaM-A, -B, -C and -D, corresponded to mRNAs of 1.8, 1.4, 2.5 and 1.8 kb, respectively, in Northern blot analysis. Our results demonstrated that the 'multigene one-protein' principle of CaM synthesis is applicable to medaka, as well as to mammals whose CaM is encoded by at least three different genes.