Aging or senescence is a process in which individuals undergo an exponential decline in vitality, leading to death. Recent years,much progress on the molecular mechanisms underlying senescence have been made. (1) Some...
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Aging or senescence is a process in which individuals undergo an exponential decline in vitality, leading to death. Recent years,much progress on the molecular mechanisms underlying senescence have been made. (1) Some senescence-related gene such as SEN6A,hic-5,din1 and MORF 4 have been clarified; (2) In 1997, through a set of experiments sponsered by scientists of Department of Biology Massachusetts Institute of Technology, it was found that the accommulation of extrachromosomal rDNA circles (ERC) in budding yeasts nucleolus is responsible for cell-senescence and the researchers propose that when enough of these circles accumulate, they clog the nucleus and prevent the cell from reading or replicating its genome, causing it to stop dividing and ultimately to die; (3) In another work finished by National Institute on Aging and the Geron biotech company of Melo, it was proved that a cells biological clock,which tells the cell how and how many times to divide, lies in its telomeres, little bits of DNA that coat the tips of the chromosome and it was clarified that a powerful enzyme,telomerase, with the potential to rejuvenate the human bodys aging tissues could effectively extend the shortened telomere . Although there is a long way to go, scientists still believe that it will be made reality in the future to greatly extend the life-span of human.
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