Flies have been found to have reduced genetic control with age, according to a study recently published in Aging. Gene silencing – when gene expression is prevented- is key in normal functioning of cells. However researchers from Brown University found that as flies aged, genes that should be silenced for normal function are no longer being silenced, mirroring patterns found in Yeast.
The study investigated chromatin, a combination of DNA and protein packaging important in silencing or allowing gene expression. The way that chromatin is structured affects how accessible the DNA is for proteins involved in converting the information stored in the DNA into gene products. When a gene is silenced the chromatin prevents access to the relevant section of DNA, and so no protein or other gene products are produced.Studies on yeast had already found the same pattern of reduced gene silencing with age, however until now it was not tested in other organisms. “For many years it has been suggested that one of the issues that occurs with age, leading to cellular dysfunction, is that some genes that should be silenced lose that silencing,” said Dr. Stephen Helfand, one of the authors of the paper. “It hasn’t been very well demonstrated to take place other than in yeast. So what we were trying to do in flies is see whether genes that are normally repressed lose their repression.”
Interestingly, when flies were fed a low-calorie diet the effects were reversed, suggesting that these changes are not the inevitable result of aging. So can we ditch the anti-aging skin creams and apply this information to humans? A recent study has connected heterochromatin breakdown and loss of gene control with the aging process in humans. However mechanisms to reverse this effect such as severe calorie restriction are not attractive options for humans . As a result scientists are looking into alternatives that mimick the effect of calorie restriction. “We’re trying to return the cell to a more youthful heterochromatin state with the hope that that will improve normal cell physiology and combat the loss of cellular function with age,” Helfand said.
The original paper can be accessed here.