London, May 31 : By developing an animal model, scientists at Mayo Clinic have discovered the function of two prominent tumour suppressor genes, p16 and p19, in the aging process.
It was known that both these genes were expressed at increased levels as humans and mice age, but now, researchers have indicated that p16 provides gas to accelerate cellular aging, while p19 suppresses that process.
These findings may aid in understanding the development of some characteristics associated with aging, such as loss of muscle mass and strength or cataracts, and how they might be retarded.
"Scientists interested in aging have developed mice that lack p16 or p19, but these mice were not suitable for studies on aging because they all die of cancer before they even begin to age. By crossing these mice with a mouse strain that ages five times faster than normal due to a mutation in the BubR1 gene, we were able to bypass this problem," Nature quoted the study's first author, Darren Baker, a laboratory technician at Mayo Clinic and a doctoral candidate, as saying.
The researchers further said that while there are many genes playing their respective roles in aging, the excessive production of p16 triggers aging in tissues. And on the other hand, the p19 gene actually counteracts the effects of p16.
And according to Jan van Deursen, Ph.D., a molecular biologist at Mayo Clinic, this was quite startling, as tissue culture experiments had predicted that p19 expression promotes aging.
One more vital finding of the study is that initiation and progression of aging is partly caused by the accumulation of senescent or aging cells in tissues and organs. These senescent cells have an abnormal gene expression profile and secrete proteins that damage the surrounding cells, affecting tissue and organ function and aspects of aging.
The study is published in the online issue of Nature Cell Biology.