| Résumé | Retinoic acid (RA) is a small lipophilic molecule that plays important roles in embryonic development by regulating cell proliferation, signaling and differentiation. There is compelling evidence that RA signaling controls the expression of a number of transcription factors in a spatio-temporal manner during these processes. In particular, Sox2, a transcription factor known for its involvement in stem cell fate commitment and neurogenesis may serve as a target of RA. In this study, we have used mouse embryonic carcinoma (EC) P19 cells to examine the effect of RA on Sox2 expression during neuronal and glial differentiation. Undifferentiated P19 cells express abundant levels of Sox2 during proliferation, a fact further supported by Sox2-DNA interaction throughout various stages of mitosis. In the presence of RA, P19 cells form embryonic bodies (EB) and differentiate into neurons and astrocytes in a chronological order similar to that of cell differentiation in the brain. RT-PCR, western blot and immunocytochemistry analyses show that the level of Sox2 is significantly reduced in P19 cells, as they differentiate into neurons, whereas P19 astrocytes maintain Sox2 expression. These results show that Sox2 is differentially expressed during neurogenesis and gliogenesis, suggesting its distinct functions throughout these processes. |
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