ANALYSIS OF CONNEXIN43 GENE-EXPRESSION INDUCED BY RETINOIC ACID IN F9TERATOCARCINOMA CELLS

All-trans retinoic acid (10(-7) M) induces cell-cell communication and expression of the gap junction protein connexin43 in mouse F9 teratoc arcinoma cells. Northern blot analysis revealed an increase of connexi n43 mRNA after treatment with retinoic acid, accompanied by an increas e of the mRNA of collagen IV, a differentiation marker. To address the question at what level gene expression is enhanced by retinoic acid, nuclear run-on experiments were carried out. There was no detectable c hange in the level of newly transcribed connexin43 mRNA. Therefore, we postulate a post-transcriptional mechanism responsible for the regula tion of connexin43 mRNA levels by retinoic acid.