CELL SURFACE CHANGES DURING DEDIFFERENTIATION IN THE METAPLASTIC TRANSFORMATION OF IRIS INTO LENS

Changes at the cell periphery during the dedifferentiative phase of the metaplastic transformation of iris into lens have been studied in Notophthalmus viridescens and Taricha granulosa using cell electrophoresis. Cell surface charge density increases as early as 1–3 days after lens removal. Cells of regenerates at 10–15 days after lentectomy have significantly lower electrophoretic mobilities than those of the irises of nonlentectomized newts. Decrease in surface charge density is due, at least in part, to the loss of ribonuclease- and neuraminidase-sensitive groups from the cell periphery. Loss of negatively charged groups from the cell surface appears to occur as cells go through dedifferentiation. Loss of cell surface components also occurs in the cells of the ventral iris which also undergo dedifFerentiation but do not regenerate a lens.