Nat Chem: Seven years later, it's making progress again! For the first time, British scientists have observed the formation of four spiral dna in living cells.

Introduction: !---- In 1953, Watson and Crick discovered the structure of the double helix of DNA, opening the age of molecular biology, bringing genetic research deep into the molecular hierarchy, and the "mystery of life" was opened., British scientists have observed for the first time the formation of four spiral DNA in living cells.2013, on the 60th anniversary of the publication of the double helix structure of DNA, the team led by Shankar Balasubramanian, a professor in the Department of Chemistry at the University of Cambridge, first announced the discovery of a quadrliatary DNA structure in the human genome, which is found mainly in the part of the DNA rich in ostrich (G), known as the G-Quartet (G4s), but it was not clear at the time that the specific location and function of the G-tetrahevana in the genome might be linked to certain cancers.by 2016, they found that G-tetraas were present in the DNA regions that regulate genes, especially cancer genes, suggesting that they act as gene switches.previous studies have required killing cells or using high concentrations of chemical probes to observe the formation of G4, so researchers have not tracked their actual presence in normal living cells.this time, a team led by Shankar Balasubramanian, in conjunction with researchers at Imperial College London and the University of Leeds, developed a fluorescent marker that can attach to G4 in living cells in humans, allowing them to observe for the first time how the structure is formed and its role in living cells.the study was published July 20 in The Journal of Natural Chemistry.the researchers, entitled "Single-visualization of DNA G-quadruplex formation in live cells", used a G4-specific fluorescent probe (SiR-PyPDS), which enables real-time single-molecule detection of a single G4 structure in a living cell.G4s live cell single-molecule fluorescence imaging was performed with low concentrations of SiR-PyPDS (20 nM) to provide informative measurements representing the G4 population in living cells without disrupting the formation and dynamics of G4 as a whole.single-molecule fluorescence imaging and real-time chemical capture of the unfolded G4 in living cells show that G4 fluctuates between the folding state and the unfolded state.researchers also demonstrated that G4 formation in living cells is cell cycle-dependent and is interfered with by the chemical inhibitions of transcription and replication. "This is the first time that we have been able to demonstrate that tetrahedral DNA is a stable structure produced by normal cellular processes and is present in our cells, forcing us to rethink the biology of DNA, a new area of basic biology and could open up new avenues for the diagnosis and treatment of diseases such as cancer," said Lead Researcher Dr. Marco Di Antonio of the.S. Abstract Rethinking DNA. "Now we can track G4 sons in cells in real time and directly study their biological role, ".we know it seems to be more common in cancer cells, and now we can explore what it does and how to stop it, and possibly devise new therapies." the team believes that G4s are formed in DNA to temporarily keep them open and promote processes such as transcription, in which cells read DNA instructions and prepare proteins.this is a form of "gene expression" in which part of the genetic code in THE DNA is activated.G4 appears to be more commonly associated with cancer-related genes and are widely detected in cancer cells. the team says that because they can now image a single G4 at once, they can track its role in specific genes and how they express themselves in cancer. these basics may reveal new targets for drugs that block the process. natural formation team was able to make a breakthrough in imaging a single G4, thanks to a rethinking of the mechanisms typically used to detect cell work. previously, the antibodies and molecules used by the team could identify and attach to G4, but they required very high concentrations of "probes". this means that probe molecules can destroy DNA, which inturn causes them to form G4 instead of detecting the natural formation of G4. Dr. Aleks Ponjavic co-led the study at Professor David Klenerman's lab and developed a microscope to observe this new fluorescent marker. "Scientists need special probes to look at molecules in living cells, but these probes sometimes interact with the substances we're trying to observe," said. with a single-molecule microscope, we can observe probes that are 1,000 times lower in concentration than previously used. in this case, our probe simply binds to G4 for only a few milliseconds without affecting its stability, which allows us to study the behavior of G4 in its natural environment without external influences. " for the new probe, the team used a very "bright" small dose of fluorescent molecule that could easily adhere to G4. small dosemeans that they do not need to image each G4 in the cell, but can identify and track individual G4s so that they can understand their basic biological role without affecting their overall prevalence and stability in the cells. team also found that G4s form and dissipate very quickly, suggesting that they form only to perform a function and, if they last too long, may be toxic to normal cells. .