Crystallin expression in the TVI cell line.

Abstract

The TVI cell line, derived from dorsal iris cells of adult newts (notophthalmus viridescens), was investigated for the presence of crystallins. Since there is reason to believe that iris epithelial cells are the main sources of this cell line and since iris epithelial cells are known to convert into lens cells in primary cultures, it is possible that TVI cells also possess the capacity to synthesize crystallins, those proteins characteristic of lens cells. It is also possible, however, that the large number of passages gone through by TVI cells in the past has eliminated such differentiated synthetic capacity expressed in earlier generations. Our immunoelectrophoresis studies reveal the presence of small amounts of alpha and beta crystallins, and the absence of gamma crystallins in TVI cells. Furthermore, immunofluorescence observations demonstrate that a small number of cells comparable to lens epithelial cells in crystallin composition and morphology are present in TVI cultures. In view of the fact that in the amphibian lens, epithelial cells which retain proliferative activity accumulate alpha and beta crystallins but not gamma crystallins, while fiber cells which are devoid of proliferative activity accumulate all three classes of crystallins, the present results suggest that the TVI cell line has lost the capacity to maintain lens fiber cells, which are known to be present in primary culture of iris epithelial cells.