Proto-oncogene expression during retinoic acid-induced neural differentiation of embryonal carcinoma cells.

Proto-oncogene expression is altered in P19 embryonal carcinoma cells during retinoic acid-induced neuronal differentiation. A transient three- to four-fold increase in erbB proto-oncogene expression and a similar although smaller increase in src expression was observed during the period of time when events committing the cells to differentiate were occurring, but prior to the expression of the differentiated phenotype. During the differentiation phase, the only change was a decrease in myc proto-oncogene expression. These changes were not observed in untreated controls, cell treated with retinoic acid while growing as monolayer cultures or with mutants of P19 which did not undergo neuronal differentiation in response to retinoic acid treatment, suggesting some degree of specificity for neuronal differentiation.