Changes in protein synthetic profiles during retinoic-acid induction of differentiation of murine embryonal carcinoma cells.

Analysis of two-dimensional gel electrophoretic patterns of proteins labeled with [35S]methionine was undertaken to investigate changes in gene expression in embryonal carcinoma cell line Nulli-SCC1 during the induction of differentiation in vitro by retinoic acid. The results indicate that changes in protein profiles occur long before overt morphological differentiation is observed. Studies utilizing the antimetabolite, alpha-amanitin, coupled with those involving the cell-free translation of poly(A)+ -RNA, suggest that gene expression is controlled post-transcriptionally as well as transcriptionally. In this respect, embryonal carcinoma cells appear to resemble early embryonic cells, which show evidence of multiple levels of control of gene expression during the initial stages of development and differentiation.