Commonly know to exist as as two intertwining DNA strands, the double helix- but also existing as four strands it now appears.
Quadruple-stranded DNA helices have been identified in human cancer cells after being made previously in the lab; but this is the first evidence of it occurring naturally. These are called G-quadruplexes and are formed by the interaction of for G (guanine) bases that make a square- most abundant when cells are about to divide (transitory structures). They form in telomeres and chromosomes.
Cancer cells divide rapidly, and they commonly have defects in their telomeres (a region at each end of a chromosome, which protects the end from deterioration or from fusion with neighbouring chromosomes) so the quadruple helix may be a feature unique to cancer cells. This difference means that this could be the way forward in treating cancer as they could target only the cancer cells and not harm healthy cells. Could the G-quadruplexes be blocked? Are they present in healthy cells too? Are they present by design?NewScicentist 26 January 2013
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