Elucidation of the double helix structure of the DNA by Watson and Crick was the turning point of the last century for the biological sciences. It is the most iconic image ever in biology. It satisfied all the properties of the replicator (the molecule for transmission of genetic information). 6O years after the achievement, it is the discovery of quadruple helix structure of DNA in some human cells that has got the attention of the world of biology.
These four-stranded structures, first identified in humans by Balasubramaniam et al. of University of Cambridge, are formed by interaction of four guanine bases forming a square and are hence also called G-quadruplexes. These were identified using antibodies which bind specifically to the G-quadruplexes and prevented from unfolding into the double-helix structure using pyridostatin. These are mostly found at the telomeres and during the S-phase, when cells replicate their DNA just before they divide.
Balasubramaniam thinks it possible for these quadruplexes to be induced by genome mutations and recombinations which are common in cancerous cells. If we could figure out how to target these in cancer cells, we might come up with a solution to cancer. The team has earlier shown that treatment of human breast cancer cells by pyridostatin stops them from replicating and migrating. Other questions which need to be answered are if these quadruplexes are present in some healthy cells too and if these play any role during embryonic development.
He also hints at the possibility of more natural (or synthetic) DNA structures with unimaginable potential benefits in these words
“I hope our discovery challenges the dogma that we really understand DNA structure because Watson and Crick solved it in 1353. We need to be open about what its structure is, because it’s dynamic”.
Read the full paper here:
Balasubramaniam, S., McCafferty, J., Biffi, G., Tannahill, D., Quantitative visualization of DNA G-quadruplex structures in human cells, Nature Chemistry, 20 January 2013, doi:10.1038/nchem.1548
Declaration: This post is inspired from the Weekly Writing Challenge: Iconic.