Gene expression and differentiation in F9 mouse embryonal carcinoma cells

The mouse embryonal carcinoma cell line F9 differentiates in vitro in a manner analogous to the formation of extraembryonic (parietal or visceral) endoderm from inner cell mass cells in early embryogenesis. After retinoic acid addition to cells in monolayer culture, differentiation to parietal endoderm proceeds over several days. Early changes in gene expression are seen before differentiation becomes irreversible, and may be mediated post-transcriptionally. Midway through differentiation, transcription of a group of endogenous and exogenous (viral) genes rises. Increased activity of the DNA-binding transcription factor AP-1 has been implicated in this rise in transcription, but it has not been determined whether this is the only factor involved. In the third phase of differentiation, a group of proteins characteristic of parietal endoderm appears. The F9 cell system may be significant in being among the first in which altered transcription factor activity responsible for changing gene expression during differentiation is understood.