| Research Abstract |
Troponin is a regulatory protein of muscle contraction and a functional complex of troponin T, roponin I, and troponin C. Many isoforms of troponin T were found in chicken breast muscle, using anti-troponin T antibody. The number of the isoforms is over 60, and they are classified into 4 groups, L, BN, BC, BA, in the order of expression in the breast muscle. L is the type expressed constantly in leg muscle, BN is expressed at embryonic stages, BC in young chickens, and BA in adult chickens. In contrast with the drastic transition of troponin T isoforms, troponin I and troponin C are constant in the component. By a devised two-dimensional gel electrophoresis which can analyze all the troponin components and by image analysis of the gel from the electrophoresis, we could determine the molecular ratio of T : I : C along the development of chickens. In spite of the drastic change of troponinT isoforms the ratio was 1 : 1 : 1 as expected from the function, and the accumulation of the components was found to progress coordinately all along the development. The character of expressing BN, BC, and BA was also in the muscle cells of the wing, and kept even after transplantation of breast muscle into leg muscle.
To compare the coordinate accumulation of protein, the ratio of tropomyosin and actin in smooth muscle was investigated. In this experiment, we found several tropomyosin isoforms which were roughly classified into muscle type and non-muscle type. When muscle type alone was counted its amount was less than expected, and when non-muscle type was included it is too much excess, showing a incoordinate accumulation of actin and tropomyosin in smooth muscle. Distribution of the non-muscle type isoforms has to be studied to get a final conclusion.
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