Mysterious structures discovered in human DNA - a new finding

Scientists have for the first time detected G-quadruplexes in human blood plasma using gentle processing methods. These four-stranded DNA structures were previously found only inside cells. The discovery could be useful for cancer research, as G4s are linked to gene regulation and are more common in tumors.

Scientists have for the first time obtained direct biochemical evidence of the presence of G-quadruplexes (G4) in human blood plasma. These compact four-stranded nucleic acid structures, formed from guanine, were previously detected only inside cells. The researchers used gentle sample processing methods, avoiding heating and traditional extraction, to avoid damaging the G4s. The presence of the structures was verified by two independent methods: using an antibody that recognizes G4 and a fluorescent compound that glows when binding to them. Both approaches recorded a signal. It is not yet clear whether the detected structures belong to DNA or RNA, as both can form G4s. In the next stage, scientists plan to treat samples with enzymes that break down DNA or RNA to determine the origin of the G4s. The discovery could be useful for cancer research: G4s are linked to gene regulation and are more common in some tumors, so their analysis in blood could potentially provide information about cancer. However, scientists emphasize that it is too early to use the method for diagnosis.