Transposon theory of aging: A New study reveals the aging and life span read more at here www.spinonews.com/index.php/item/893-transposon-theory-of-aging-a-new-study-reveals-the-aging-and-life-span

A new study increases and strengthens the links that have led scientists to propose the “transposon theory of aging.”

Transposons are rogue elements of DNA that break free in aging cells. As cells get older, tightly wound heterochromatin wrapping that typically imprisons transposons becomes looser, allowing them to slip out of their positions in chromosomes and move to new ones, disrupting normal cell function.

Meanwhile, scientists have shown that potentially related interventions, such as restricting calories or manipulating certain genes, can demonstrably lengthen lifespans in laboratory animals.

The new results, led by Jason Wood from Brown University, come from several experiments that are thorough and direct in connecting the dots among weakening heterochromatin, increased transposing expression, aging, and life span.

In one set of experiments, they inserted special genetic snippets into fat body cells, the equivalent of human liver and fat cells in flies that would glow bright green when specific transposable elements move about in the genome.

Under the microscope, the scientists could see a clear pattern of how the glowing “traps” lit up more and more as the flies aged. Wood says, increase in transposon activity was not steady as flies grew older. Flies reach a certain age and then it takes off more exponentially.

The data show that the time frame in which transposable element activity really begins to increase is tightly correlated with the time when the flies start to die.

To further explore the connection between transposing expression and lifespan, the team tested the effects of manipulating genes known to improve heterochromatin repression that is not only found in flies, but also in mammals. For example, increasing expression of the gene Su(var)3-9, which helps form heterochromatin, extended maximal fly lifespan from 60 to 80 days.

Wood says, the transposons appear to be a significant factor in aging. There are lots of potential mechanisms that influence the aging process but we think this is one of them.