Monday, January 21, 2013

Quadruple Helix DNA

Scientists Spot Quadruple Helix DNA Working in Human Cells

Forget the humble double helix: scientists from Cambridge University have now spotted four-stranded strings of DNA working inside human cells.

The researchers have published a paper in Nature Chemistry which demonstrates the existence and function of quadruple helix human DNA. The researchers believe it might be related to cancer—and that understanding it could be key to treating the disease in the future. Prof Shankar Balasubramanian from Cambridge University explains to the BBC:
"The existence of these structures may be loaded when the cell has a certain genotype or a certain dysfunctional state. We need to prove that; but if that is the case, targeting them with synthetic molecules could be an interesting way of selectively targeting those cells that have this dysfunction."
The four-stranded DNA is known as the G-quadruplex. That "G" refers to guanine, which is one of the four chemical bases which form DNA, and it seems the quadruple helix tends to form wherever there are unusually high concentrations of the base. The team were able to spot the G-quadruplex in human cells by creating proteins that bind to its structure—made possible by the fact that it's been spotted before in microscopic organisms called ciliates. The scientists watched as the quadruplex became more prevalent during cell division.

Now the researchers know that the four-stranded DNA is present in humans, they're set to explore its implications for cancer treatment. "I'm hoping now that the pharmaceutical companies will bring this on to their radar and we can perhaps take a more serious look at whether quadruplexes are indeed therapeutically viable targets," Balasubramaninan told the BBC. Here's hoping he's onto something. [Nature Chemistry via BBC]