Molecular cloning of the chicken gizzard telokin gene and cDNA

Telokin is a protein which consiste of the C-terminal portion of smooth muscle myosin light chain kinase (MLCK) (M. Ito, R. Dabrowska, V. Guerriero, Jr., and D. J. Hartshone (1989) J. Biol. Chem. 264, 13971-13974). In this study, the chicken gizzard telokin cDNA and gene were cloned and analyzed. The telokin cDNA coded 157 amino acid residues which were completely identical to the C-terminal portion of the amino acid sequence of chicken gizzard MLCK. The telokin gene was coded in a 6.3-kb EcoRI genomic fragment and it consisted of three exons. The 5'-leader sequence of the telokin cDNA and genomic sequence revealed that the telokin gene was included in the MLCK gene and the transcription started in the intronic sequence of the MLCK gene. The analysis of the telokin gene suggests that the telokin expression was under the control of an independent promotor. Northern blotting and the reverse transcriptase-polymerase chain reaction methods revealed that telokin was expressed not only in chicken gizzard but also in chicken heart, lung, intestine, and skeletal muscle although the levels of the expression in the latter were much less than that in the gizzard.