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Parasitic DNA proliferates in aging tissues

By Guest PostJanuary 5, 2014Healthaging tissues, cancerous tissue, cancerous tumors, cell culture, DNA, fruit fly drosophila, hepatocellular carcinoma, jill kreiling, john sedivy, journal aging, lymphoma, marco dececco, normal tissues, parasitic dna, replicative senescence, retrotransposable elements, robert reenan, rtes, stephen helfand

As mice age, cells in tissues such as the liver and skeletal muscle lose control over rogue sequences of DNA called “retrotransposable elements,” according to new research in the journal Aging. The elements, which may undermine health, could proliferate in old mice and were also abundant in cancerous tissue. A low-calorie diet, however, restrained their advance.

PROVIDENCE, R.I. [Brown University] — The genomes of organisms from humans to corn are replete with “parasitic” strands of DNA that, when not suppressed, copy themselves and spread throughout the genome, potentially affecting health. Earlier this year Brown University researchers found that these “retrotransposable elements” (RTE’s) were increasingly able to break free of the genome’s control in cultures of human cells. Now in a new paper in the journal Aging, they show that RTEs were increasingly able to break free and copy themselves in the tissues of mice as the animals aged. In further experiments the biologists showed that this activity was readily apparent in cancerous tumors, but that it also could be reduced by restricting calories. (more…)

Locked RNA Editing Yields Odd Fly Behavior

At the level of proteins, organisms can adapt by editing their RNA — and an editor can even edit itself. Brown University scientists working with fruit flies found that “locking down” the self-editing process at two extremes created some strange behaviors. They also found that the process is significantly affected by temperature.

PROVIDENCE, R.I. [Brown University] — Because a function of RNA is to be translated as the genetic instructions for the protein-making machinery of cells, RNA editing is the body’s way of fine-tuning the proteins it produces, allowing us to adapt. The enzyme ADAR, which does this editing job in the nervous system of creatures ranging from mice to men, even edits itself. In a new study that examined the self-editing process and locked it down at two extremes in fruit flies, Brown University scientists found some surprising insights into how this “fine-tuning of the fine-tuner” happens, including bizarre behavioral effects that come about when the self-editor can’t edit. (more…)

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Parasitic DNA proliferates in aging tissues

Locked RNA Editing Yields Odd Fly Behavior