Cells inside our body keep dividing regularly, as is the scheme of the nature. However, if the division fails to take place, the cells will eventually die, leading to the chance of developing age-related diseases as well as cancer.
There are stretches of Deoxy Ribonucleic Acid (DNA) called telomeres present at the ends of chromosomes like protective caps. During cell division, these telomeres become shorter which makes the productivity of the protective cap less effective. Hence, the telomeres need to be checked upon regularly and elongated because if these DNA components get too short, the cell will stop dividing and move towards cell aging.
Scientists have studied what helps the telomeres to function properly and have found that a RNA species called TElomeric Repeat-containing RNA (TERRA) helps to work like the maintenance mechanic for telomeres. These get recruited at sites where telomeres need regulation and send a signal indicating that the telomeres need to be elongated or repaired. Which form of a system sends TERRA to the chromosome end is not known.
TERRA are a type of molecules called the non-coding RNAs, which do not get translated into proteins but instead function as chromosomes’ structural components. To study how these were getting assigned to places and remaining there, scientists visualized TERRA molecules under a microscope and found that a short stretch of the ribonucleic acid (RNA) was instrumental to bring it to the telomeres.
Now once TERRA has reached its required location, several proteins regulate its association with telomeres. Here, a protein called RAD51 plays a crucial role. Scientists from Ecole Polytechnique Fédérale de Lausanne and Masaryk University found that RAD51 was helping TERRA stick to telomeric DNA to form a so-called RNA-DNA hybrid molecule.
This sort of hybrid molecule formation has been previously detected only in the case of DNA repair. To witness it taking place during telomere repair is revolutionary.