Stimulation of crystallin synthesis in embryonic brain cells in culture.

Expression of δ-crystallin, a lens-specific protein, in 6-day-old chick embryonic brain cells was examined in situ and in vitro. The presence of minute amounts of δ-crystallin and its mRNA (δ-mRNA) in brain cells in situ was demonstrated by immunoblot and Northern blot analysis. In spreading cultures of the brain cells, δ-crystallin and δ-mRNA showed a significant increase from their in situ level. Immunohistological staining (peroxidase antiperoxidase) with monospecific anti-serum against δ-crystallin revealed that δ-producers were both epithelial cells and dendritic cells. Neither lentoidogenesis nor α-crystallin expression was observed. Stimulation of δ-crystallin synthesis in cultured brain cells differed when compared with transdifferentiating cultures of neural retina cells. In the latter, δ-crystallin synthesis occurred concomitantly with differentiation of morphologically distinct lens cells containing α-crystallin.