Human Genome Found To Contain Quadruple Helix DNA Strands
January 21, 2013

Quadruple Helix DNA Strands Discovered By UK Scientists

redOrbit Staff & Wire Reports - Your Universe Online

On the 60th anniversary of the publication of the paper describing the double-helix structure of DNA, researchers from Cambridge University reportedly have proven the existence of four-stranded “quadruple helix” DNA structures within the human genome.

It was in 1953 that James D. Watson and Francis Crick, also of Cambridge University, published a paper which described the interweaving structure of the double-stranded molecules that contain the genetic code for all living things. Now, in research published in the journal Nature Chemistry, scientists describe the quadruple helix structures known as G-quadruplexes.

G-quadruplexes form in zones of DNA that are rich in guanine, a nucleobase or building block that is also known simply as “G,” the university explained in a January 20 statement.

The findings of the study, which was funded by Cancer Research UK, were announced after more than a decade of research that involved computer modeling, laboratory experiments, and ultimately, the use of fluorescent biomarkers to identify the structures in human cancer cells.

“The research“¦ goes on to show clear links between concentrations of four-stranded quadruplexes and the process of DNA replication, which is pivotal to cell division and production,” Cambridge University officials explained. “By targeting quadruplexes with synthetic molecules that trap and contain these DNA structures — preventing cells from replicating their DNA and consequently blocking cell division — scientists believe it may be possible to halt the runaway cell proliferation at the root of cancer.”

"We are seeing links between trapping the quadruplexes with molecules and the ability to stop cells dividing, which is hugely exciting,” added Shankar Balasubramanian, the lead researcher and a professor in the university´s Department of Chemistry. "The research indicates that quadruplexes are more likely to occur in genes of cells that are rapidly dividing, such as cancer cells. For us, it strongly supports a new paradigm to be investigated - using these four-stranded structures as targets for personalized treatments in the future."

Previously, scientists have demonstrated that quadruplex DNA could form in test tubes, but it was generally not believed such structures could be found in nature. The Cambridge University team´s new research, however, shows not only can they occur, but they actually form in the DNA of human cells. According to officials at Cancer Research UK, this knowledge could be used to help treat the disease.

“This research further highlights the potential for exploiting these unusual DNA structures to beat cancer — the next part of this pipeline is to figure out how to target them in tumor cells," said Dr. Julie Sharp, the organization´s senior science information manager. "It's been sixty years since its structure was solved but work like this shows us that the story of DNA continues to twist and turn."

"The 'quadruple helix' DNA structure may well be the key to new ways of selectively inhibiting the proliferation of cancer cells. The confirmation of its existence in human cells is a real landmark,” added Balasubramanian.