Tissue-specific expression of a chicken calmodulin pseudogene lacking intervening sequences.

An eel calmodulin cDNA probe has been used to isolate a calmodulin gene from a chicken DNA library. Sequence analysis revealed this calmodulin gene (cCM1) to contain the nucleotides that code for 148 amino acids, a termination codon, and 486 residues of 3'-noncoding sequence before an A-A-T-A-A-A poly(A) addition signal. The amino acid sequence derived from these nucleotides is 87% homologous to that of bovine brain calmodulin. cCM1 is one of two calmodulin genes in the chicken genome but is unique in that it does not contain intervening sequences to interrupt the structural segments of the protein. This suggests that cCM1 originated as a processed gene copy derived from the other calmodulin gene, cCL1, a circumstance usually associated with pseudogenes. In contrast, cCM1 appears to be a functional member of a multigene family whose expression is specific for muscle cells.