[The degree of methylation of alpha-fetoprotein in rat hepatoma cell lines and their clones producing and not producing this protein].

The extent of methylation of MspI-HpaII sites of alpha-fetoprotein (AFP) gene in DNAs from normal rat livers, rat hepatoma cell lines and their clones was compared by Southern blot hybridization. The expression of this gene was controlled by measuring the level of AFP specific RNA and by immunoperoxidase staining with antibodies to AFP. It was found that the AFP gene contained several CCGG sites in the 5'-region methylated in the nonproductive cell lines and normal adult liver and undermethylated in productive cell lines. The same phenomena was observed for productive and nonproductive hepatoma McA-RH7777 clones. These findings suggest that specific changes in the methylation pattern are associated with changes in AFP gene expression.