The telomeres, these regions which are found at the end of the chromosomes, and to which we attributed only a protective function of the genome, have just seen their status change. An article published in the very serious journal PNAS actually relates “the discovery of two proteins which would be encoded by sequences found in telomeres, one of which is found in large quantities in certain human cancers”, writes the site iflscience.com.
“The discovery that telomeres code for proteins will change our understanding of cancer, aging and how cells communicate with each other,” says Jack Griffith, professor of microbiology and immunology at the University of North Carolina, in the United States.
These structures, which until now were thought to carry no genetic information, are made up solely of repeating DNA sequences and play a key role in aging. In effect, “When a cell divides, the telomeres get shorter, so after a certain number of divisions the cell stops dividing and dies, tells the news site. A mechanism that guarantees the cell not to accumulate too many mutations over time but, above all, that provides it with an effective defense against cancer, the primary characteristic of which is rapid cell division.”
VR and GL
Unlike most proteins in the human body, the two newly discovered proteins consist solely of repeats of two amino acids. The first has valine (V) and arginine (R) repeats, it is called VR. The second consists of glycine (G) and leucine (L) repeats. “These two proteins are signal proteins, essential for triggering chains of reactions involving other proteins which, ultimately, provide important biological functions”, precise iflscience.com. During their experiments, the scientists noticed that the VR protein was present in large quantities in certain cancer cells and in people with diseases affecting their telomeres.
According to Taghreed Al-Turki, a postdoc in Jack Griffith’s lab, “the amount of VR and GL proteins would increase with the age of the individual. which would allow [aux scientifiques] to use them as a biomarker of aging to assess the biological age of an individual.”
Much remains to be discovered when it comes to VR and GL, but for now researchers prefer to focus on the “development of a blood test that would detect, [indirectement grâce à VR et à GL]the presence of cancer or inflammation”, conclut Jack Griffith.