Members of a protein subfamily have been found to have demethylase activity, according to two papers to be published online by Nature. They show that the enzymes alter the structure of the protein-DNA complex called chromatin.
In chromatin, DNA is wrapped around proteins called histones. Specific patterns of methyl groups attached to one histone, H3, are involved in silencing genes and have been thought to be permanent chromatin marks. Kristian Helin and colleagues show that an enzyme called GASC1 (also called JMJD2C), and others in the same family, remove these methyl groups and thus alter the chromatin structure and consequently gene expression.
Production of GASC1 was previously known to be boosted in some human cancers, and the researchers show that blocking this enzyme cuts cell proliferation, suggesting that such an approach could stall the runaway cell division in cancer.
In a linked paper, Yi Zhang and colleagues show that the related protein JHDM3A (also called JMJD2A) also removes methyl groups from histone H3 and can change chromatin structure and the expression of genes when overexpressed.
Kristian Helin (Biotech Research & Innovation Centre, Copenhagen, Denmark)
Yi Zhang (The University of North Carolina, Chapel Hill, NC, USA)
(C) Nature press release.
Message posted by: Trevor M. D'Souza