When DNA gets into, RNA gets involved

DNA gets tangled. For example, Its two strands are usually arranged in double propeller, or DNA duplex. However. Furthermore, when they separate and thus authorize the reading of genetic information, it happens that they fold up on themselves and form kinds of nodes. Moreover, This is particularly the case with regions rich in guanine molecules (G)-one of the four DNA constituents-. Furthermore, where the interaction of four of these molecules creates “g-quadruplexes” (G4). Therefore, These nodes – whose function is not yet fully understood – would help regulate the expression of genes. Similarly, but they could also harm the stability of the genome by acting as obstacles to the replication of DNA, even its transcription by RNA. Nevertheless, The sequences where the formation of G4 is possible represent approximately 1 % of our genome. which is colossal comparatively, for example, to the sequences when dna gets into, rna coding proteins, which cover about 2 %. Faced with such an abundance. and the risks linked to G4, cells have developed mechanisms that unravel DNA, but they remained misunderstood. Koichi Sato. of the Oncode Institute, in Utrecht, in the Netherlands, and his colleagues now describe such a mechanism, notably involving a RNA.

This process brings into play “R curls”. “G curls”. The R curls are hybrid duplexes made up of a bit of DNA and a bit of RNA. When a buckle R is formed on the complementary strand to that of the G4. therefore in front of the node, the structure created is called “Lecle G”. The Koichi Sato team postulated that the G loop is required to unroll the G4. To demonstrate this, the researchers used xenope eggs, a frog when dna gets into, rna very often used as a model organism in the laboratory. They injected them with DNA containing a G4, then identified the proteins that interacted with the node. Result: among them are DNA repair proteins. which is surprising since DNA is simply distorted and not damaged here, but also enzymes (Helicases) in charge of unrolling the G4. The study reveals that the formation of loop G is required for the resolution of the G-Quadruplexes. and that it disasses itself once its task is accomplished.

“Taken separately. these events, and the proteins involved, are known,” comments David Monchaud, CNRS research director at the Institute of Molecular Chemistry of the University of Burgundy. “” The existence of G4. R -loops has indeed been established for fifty years, and that of the G loop, for twenty years, but the coordination of their roles when dna gets into, rna is completely original here. This mechanism therefore represents a new system for preserving genomic stability. offers new therapeutic targets to understand and control the instability of the genome, widespread in genetic diseases, including cancers. Fostering G4. preventing their detangling could indeed cause DNA damage, to which cancer cells are more sensitive than healthy cells due to a generally deficient repair system.