Discovered in vitro back in the 1990s, a new unique structure of DNA has just been confirmed in living cells beyond the confines of a petri dish-nursery. A research team from the Garvan Institute of Medical Research in Sydney observed the intercalated-motif structure (i-motif) occurring naturally in humans.

Going beyond the double helix

When most of us think of DNA, we imagine the classic double helix sequence, but there are actually multiple different structures which make up our genetic code.

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These include A-DNA, Z-DNA, triplex DNA, and Cruciform DNA, and the significance of each one is linked to when and where they are formed within the cell.

Our man on the inside

In order to identify the i-motifs in living cells, the research team developed an antibody called iMab, which would specifically recognize and bind to i-motif DNA structures. Once found, the team merely had to look for an immunofluorescence given off by the iMab which would shed light on the i-motif.

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There is still plenty of speculation of what the i-motif structure does and how. It seems to form towards the end of a cell’s lifespan, in areas known as ‘promoter-regions’—areas of DNA which control whether genes are turned off or on, as well as in the telomeres—genetic markers well known to be associated with aging.

A supply with a new demand

As scientists discover new DNA structures like i-motif or G4 DNA—discovered in 2013—Medhi Zeraati, a member of the research team and one of the authors of the new corresponding literature thinks it will compel scientists to further study them.

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“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,” he told Sciencealert, adding that pathological consequences could exist for failing to understand i-motif and the other forms of DNA within our cells.