Muscle dedifferentiation and contractile protein synthesis during post-traumatic regeneration by Owenia fusiformis (polychaeta annelid).

During anterior traumatic regeneration of the polychaete annelid Owenia fusiformis, we have observed by electron microscopy the dedifferentiation processes of muscle cells. The dedifferentiated cells are reminiscent of undifferentiated myoblasts. They form the blastema and redifferentiate in muscle cells in the regenerate. The in vivo and in vitro biochemical studies of the biosynthesis of contractile proteins, as markers of the terminal differentiation programme of the muscle cells, showed that gene expression correlated with the terminal differentiation programme (at last for muscle cells) seemed unaffected. It seems in fact that contractile protein synthesis is regulated partly at the translational level during traumatic regeneration in the invertebrate.