Kiwi boffins in DNA discovery

Researchers’ finding could open door to breakthrough on understanding disease

What we know about diseases as common as cancer, diabetes and dementia could be transformed following ground-breaking findings by Kiwi researchers.

The new study by scientists from Auckland University’s Liggins Institute, Otago University and Massey University has revealed fresh insights into mitochondria and the littleunderstood role they play in the development of our bodies.

Measuring just a 1000th of a millimetre each, mitochondria DNA are specialised sub-units of cells that act as their batteries or generators, as they supply most of the cell’s energy.

The more energy-hungry a type of cell is, the more mitochondria it contains, ranging from several to thousands of them.

We receive the DNA in our cells’ nuclei — organised into chromosomes — from both parents, but we inherit our mitochondrial DNA from our mothers only.

Mutations in the mitochondrial DNA are relatively common, affecting one in a few thousand people, and are linked to common illnesses along with a wide range of fatal or progressively debilitating diseases, including diabetes, gastrointestinal disorders, heart disease, dementia, deafness, and eye disorders.

But now there are new reasons to suspect their roles in disorders.

In their new study, published in the journal Mitochondrion, the researchers have shown for the first time that human mitochondrial DNA leaves the mitochondria, travels into the host cell nucleus and connects to specific genes.

“We found evidence that mitochondria DNA and nuclear DNA ‘talk Researchers have shown for the first time in humans that mitochondrial DNA travels into the host cell nucleus and “talks to” specific genes on the DNA. Mitochondrial DNA may influence gene expression. This finding could be a key to understanding how mitochondrial DNA mutations manifest as disease. to each other’, and these interactions aren’t random,” said lead researcher Dr Justin O’Sullivan, a Liggins molecular geneticist.

The findings give weight to the idea that mitochondria do much more than supply energy and regulate a cell’s metabolism — the processes that keep it alive.

“We think the connections we detected are part of a feedback system between mitochondria and the cell nucleus that may influence how humans grow and develop throughout life,” O’Sullivan said.

Interactions between the two sets of DNA within our cells could be one of the ways the environment influences gene expression, he said.

One theory about mitochondrial disease is that the damaged -mitochondria fail to supply enough energy to the cell so it can’t work properly.

But this latest finding suggests another possible culprit: problems with the way the mitochondrial and nuclei DNA “talk” to each other — or fail to talk to each other.