A well-characterised experimental system, the myogenin gene in C2C12 muscle
cell culture, was chosen to better understand the methylation mechanism un
derlying the regulation of gene expression. We already demonstrated that de
methylation dynamics of a specific CpG site in the 5'-flanking region of my
ogenin well correlates with gene expression and terminal differentiation. H
ere we demonstrate that S-adenosylmethionine-sulphate-p-toluenesulphonate (
SAM) inhibits myogenin expression and myoblast differentiation by delaying
the demethylation of specific CpG in differentiating myoblasts. These resul
ts suggest new perspectives in methylation mechanisms and the use of SAM in
the partial silencing of gene expression, as it could be required in disea
se treatment. (C) 2001 Published by Elsevier Science B.V. on behalf of the
Federation of European Biochemical Societies.