STABILITY OF CHICKEN TROPONIN-T EXPRESSION IN CULTURED MUSCLE-CELLS

Cells prepared from chicken skeletal muscles of early developmental st ages were cultured to study their troponin T isoform expression. using antisera specific to fast- and slow-muscle-type isoforms, and compare d with the cells from later stages described in the previous study (Ma shima et al., 1996). We found that cultured myogenic cells from chicke ns and chick embryos could be classified, as in the previous study, in to two types, fast type and fast/slow type in which fast- and slow-mus cle-type isoforms were coexpressed. Ratios of these two types of muscl e cells varied depending on their origins and developmental stages, an d fast/slow type cells were in the majority at early stages. Since two distinct populations of cells committed to myogenic cell lineages wer e supposed to give rise to the two types of myotubes, we investigated the intrinsic stability of troponin T expression of the cultured myoge nic cells using the serial subcloning method. The results of clonal an alysis suggested that the expression pattern of troponin T isoform in cultured muscle cells is stable and that myogenic cell lineages play a n important role in giving rise to different muscle types.