Scientists at the University of North Carolina have discovered that telomeres contain the genetic information for the production of two small proteins that are involved in the development of cancer and aging. This is reported in an article published in the journal Proceedings of the National Academy of Sciences (PNAS).
Telomeres are a DNA sequence made up of TTAGGG repeats that prevent chromosomes from binding to each other. As cells divide, telomeres shorten, and eventually become so short that the cell can no longer divide normally and dies.
In 2011, scientists discovered a six-base molecule that can generate a series of toxic proteins made up of two repeating amino acids. The similarity of this RNA to RNA produced by telomere transcription was noted, and the researchers hypothesized that the same mechanism may be at work in both cases.
In the new work, the scientists showed that telomeric DNA contains instructions for the production of signal proteins, designated VR (valine-arginine) and GL (glycine-leucine), according to the types of amino acids they are composed of. Signal proteins are molecules that trigger a cascade of biochemical reactions involving other intracellular proteins. The VR protein is present in increased amounts in some human cancer cells, as well as in the cells of patients suffering from telomere defect diseases.
The authors believe that with age, the amount of VR and GL in the blood steadily increases, which is a new biomarker of biological age in contrast to chronological age.