MELBOURNE, July 22 (Xinhua) -- Scientists in Australia have uncovered new insights into how cells regulate DNA methylation, a fundamental process that helps keep potentially harmful viral elements in our genome under control.
The study, led by Australia's Peter MacCallum Cancer Center and published in Nature Genetics, focused on understanding how the enzyme DNMT1, which maintains DNA methylation, is regulated within cells, according to a Peter Mac statement on Wednesday.
Human DNA contains about 20,000 genes, accounting for only around 2 percent of the genome, while more than half of our DNA consists of ancient viral sequences that entered the human genome millions of years ago during evolution, the statement said.
Researchers said cells keep these viral elements silent through DNA methylation, which attaches chemical tags to DNA that prevent harmful viral sequences from becoming active.
Scientists have long known that DNMT1 maintains DNA methylation, but how its activity is regulated has remained unclear. Peter Mac clinician-scientist Jesse Balic, who co-led the study, said learning how to precisely manipulate this enzyme could open new avenues for treating cancer and other diseases.
The researchers found that blocking DNMT1 with specific drugs reduced DNA methylation, reactivating previously silent viral regions of the genome.
"Even though there is no real virus present, the cell acts as if it is under attack, triggering an internal antiviral response that can lead to cell death," said Peter Mac Professor Mark Dawson, adding that a better understanding of the process could help researchers selectively target cancer cells.
Because DNA methylation is also used by most plants and animals, the research may have implications beyond medicine, including agriculture, Dawson said. ■