A New DNA structure inside Human Cells

Scientists discovered a ‘twisted knot’ of DNA in human cells, confirming that our double helix structure is crafted with more intricate symmetry.

Australian researchers have identified a new DNA structure, called the i-motif, inside cells. A twisted ‘knot’ of DNA, the i-motif has never before been directly seen inside living cells.

Above, an illustration of the “twisted knot” DNA structure.  Credit Zeraati et al., Nat Chem, 2018

Deep inside the cells in our body lies our DNA. The information in the DNA code – all 6 billion A, C, G and T letters – provides precise instructions for how our bodies are built, and how they work.

The iconic ‘double helix’ shape of DNA has ca­ptured the public imagination since 1953, when James Watson and Francis Crick famously uncovered the structure of DNA. However, it’s now known that short stretches of DNA can exist in other shapes, in the laboratory at least – and scientists suspect that these different shapes might play an important role in how and when the DNA code is ‘read’.

The new shape looks entirely different to the double-stranded DNA double helix.

Associate Professor Daniel Christ (Head, Antibody Therapeutics Lab, Garvan) who co-led the research, said:

“When most of us think of DNA, we think of the double helix. 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.

A 'twisted knot' of DNA in human cells

An illustration overlaid on imaging of the iMab antibody (green) in the nuclei of cells.  Credit Chris Hammang

The new findings, from the Garvan Institute of Medical Research, are published in the journal Nature Chemistry.

via gizmodo