Expression of neuronal markers in chick and quail embryo neuroretina cultures infected with Rous sarcoma virus.

Cultures of neuroretina (NR) cells from 7-day chick and quail embryos were infected with ts NY-68, a thermosensitive mutant of Rous sarcoma virus (RSV) which transformed NR cells at 36 degrees C. The following differentiation markers for neurones were studied: tetanus toxin-binding sites at the cell surfaces, presence of synapses, and the specific activity of the enzymes choline acetyltransferase (CAT) and glutamic acid decarboxylase (GAD). Appearance of synapses and expression of CAT were similar in control and transformed cultures. Tetanus toxin-binding cells were observed in transformed primary cultures and also in quail NR subcultures. GAD-specific activity was markedly stimulated in chick and quail primary cultures transformed by ts NY-68 and further increased in subcultures of ts NY-68-transformed quail NR cells. Stimulation of GAD activity is controlled by the transforming (src) gene of RSV since it was not observed in cultures infected with RAV-1, a leukosis virus which lacks the src gene. These data show that infection of chick and quail NR cultures with RSV results in the transformation of cells with neuronal markers.