Lens-specific mRNA in cultures of embryonic chick neural retina and pigmented epithelium.

Messenger RNA (mRNA) from cultures of 8-day embryonic chick neural retina and pigmented epithelium has been characterised by cell-free translation and by hybridisation to complementary DNA (cDNA) which is complementary to the most abundant mRNAs isolated from the day-old chick lens. In neural retina cultures cell-free translation of total RNA gives detectable crystallin products by 19 days in culture and the proportion of crystallin products gradually increases as the cultures progress, until at 42 days crystallins are the most prominent products. Hybridisation with cDNA showed that by 42 days in culture there is a 500-fold increase in the level of lens-specific mRNA relative to total mRNA. Most of this increase occurs during the final 12 days of Culture. The levels of lens-specific mRNA also increase significantly in pigmented epithelium cultures—by 60 days in culture there is an 80-fold increase over the level in the starting material. The results provide evidence for transcriptional control of crystallin synthesis during culture.