The new shape looks entirely different to the double-stranded DNA double helix. “When most of us think of DNA, we think of the double helix,” says Associate Professor Daniel Christ (Head, Antibody Therapeutics Lab, Garvan) who co-led the research. “This new research reminds us that totally different DNA structures exist — and could well be important for our cells.” “The i-motif is a four-stranded ‘knot’ of DNA,” says Associate Professor Marcel Dinger (Head, Kinghorn Centre for Clinical Genomics, Garvan),.who co-led the research with A/Prof Christ. “In the knot structure, C letters on the same strand of DNA bind to each other — so this is very different from a double helix, where ‘letters’ on opposite strands recognise each other, and where Cs bind to Gs [guanines].”Garvan Institute of Medical Research, “Found: A new form of DNA in our cells” at ScienceDaily
At first the researchers only found them in the lab but they have recently found them in a number of different human cell lines.
The researchers showed that i-motifs mostly form at a particular point in the cell’s ‘life cycle’ — the late G1 phase, when DNA is being actively ‘read’. They also showed that i-motifs appear in some promoter regions (areas of DNA that control whether genes are switched on or off) and in telomeres, ‘end sections’ of chromosomes that are important in the aging process.
Dr Zeraati says, “We think the coming and going of the i-motifs is a clue to what they do. It seems likely that they are there to help switch genes on or off, and to affect whether a gene is actively read or not.”Garvan Institute of Medical Research, “Found: A new form of DNA in our cells” at ScienceDaily
The paper is closed access.
And it all just sort of happened, right? Swishes of chemicals will do the trick.