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Drug resistance clue

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Drug resistance clue

A chance discovery by Faculty of Dentistry researchers has uncovered a piece of genetic sleight-of-hand that may be contributing to the global problem of multi-drug resistance.

Research leader Dr Erwin Lamping (Sir John Walsh Research Institute) says the basic process of gene mutation is the key.

"When a gene mutates, its original function is lost. However, organisms can adapt to this with gene duplication – if one copy mutates and changes its function, the organism still has the original gene with its original function. This allows organisms to develop a range of different functions or abilities."

While investigating drug-resistance in yeast – a cause of many common human infections – the team discovered a gene encoding a protein that pumps drugs out of yeast cells. Right next to it was a seemingly identical, tandem-duplicated gene with only six short regions being different – the result of gene mutation.

"We carefully studied genes from seven yeast strains from different parts of the world and found 30 copies of the pump genes, all with the same pattern: they had large regions that were identical and six small regions that differed, enabling the pumping of different drugs," he says.

"This repetition of almost identical genes, but with different functions, may have gone largely unnoticed in other organisms, including humans.”

He says it may help explain why cancer cells become multi-drug resistant, why people react differently to drugs and why some drugs do not work for some people, potentially leading to new ways to overcome drug resistance in humans.

Photo: Graham Warman