Gene Expression of Myofibrillar Proteins in Single Muscle Fibers of Adult Chicken: Micro Two Dimensional Gel Electrophoretic Analysis1

Using a micro two dimensional gel electrophoretic system and silver stain method, we examined the isoform patterns of myofibrillar proteins in single muscle fibers of adult chicken. Several isoforms of myosin light chains, tropomyosin, troponin T, troponin I, and troponin C were identified. Analysis of pectoral, anterior latissimus dorsi, sartorius and soleus muscle revealed that single fibers contained either fast or slow form of each of the troponin subunits, indicating that troponin exists as a 'homocomplex.' The form of troponin in a given cell was associated with that of myosin light chains. The form of tropomyosin, however, was not associated with those of myosin light chains and troponin, but was tissue specific. Overall, we found four combinations of isoforms of myosin light chains, troponin subunits and tropomyosin subunits. In adult dystrophic chicken the isoform patterns of tropomyosin and troponin T in single fibers of pectoral muscle markedly deviated from the normal patterns.