Quadruple Helix DNA May Provide New Insights to Cancer

James Watson and Francis Crick may have discovered the double helix, but they probably didn't know there was also a "quadruple helix." Scientists from Cambridge University state that they have seen four-stranded DNA at work in human cells for the first time and that this formation of DNA may relate to cancer.

The four-stranded DNA is actually known as the G-quadruplex, with the "G" standing for guanine, one of the chemical components that make up a DNA strand. For a number of years, the team had been pursuing the four-stranded version of the molecule that scientists had previously only been able to produce in a test tube.

In their study, which was published in the journal Nature Chemistry, the scientists tracked down the quadruple helix. They created antibody proteins that were specifically designed to bind to regions of human DNA that were rich in the quadruplex structure. In order to watch these antibodies at work, the scientists tagged them with a fluorescence marker.

What did they find? The four-stranded DNA was most frequently seen during the s-phase of DNA replication when a cell copies its DNA just prior to dividing. The fact that the quadruplex DNA was seen at this stage means that it's of key interest in the study of cancer, which is usually driven by genes that have mutated to increase DNA replication.

It's possible that the creation of synthetic molecules that contain the quadruple helix structure could block the runaway cell proliferation at the root of tumors, according to BBC News. That could have major implications for the study of cancers in the future.