Scientists Capture DNA Strands "Zipping" Together, Offering New Clues to Cancer and Genome Organization
核心洞察
Researchers used high-resolution atomic force microscopy and molecular dynamics simulations to directly visualize DNA (搜索)-DNA recognition for the first time, confirming a mechanism proposed more than 20 years ago.
The study shows positively charged divalent ions such as magnesium and calcium act as molecular bridges that hold neighboring DNA (搜索) helices in a groove-to-groove alignment.
The team identified specific DNA (搜索) sequence motifs that form hotspots where pairing occurs more readily, regions that may matter when mutations disrupt normal cellular processes in cancer (搜索).
Researchers have captured the first direct visual evidence of how separate DNA (搜索) molecules align and interact, providing experimental support for a mechanism scientists have debated for more than two decades. The findings, published in Nucleic Acids Research, describe how neighboring DNA strands recognize matching sequences before the cell's specialized machinery takes over—a process with implications for chromosome organization, genome regulation, and cancer (搜索).
The study combined high-resolution atomic force microscopy, which images molecules at the nanoscale, with advanced molecular dynamics simulations. Together, the techniques allowed the team to observe DNA (搜索) pairing in unprecedented detail and to reconstruct topographical maps showing how the molecules were positioned, while simulations tracked individual atoms and ions as they moved around the DNA.
Groove-to-Groove Alignment via Ion Bridges
The team found that neighboring DNA (搜索) molecules can align in a highly organized "groove-to-groove" arrangement. Rather than coming together randomly, the strands appear to be held in place by positively charged divalent ions such as magnesium and calcium, which act as tiny molecular bridges between the negatively charged DNA molecules.
The simulations showed that double-charged metal ions can behave like two charged arms, each interacting with both DNA (搜索) molecules at once to form a bridge across the space separating them and helping hold the two strands in alignment. Researchers described the process as supporting a long-theorized "DNA zipper" model, in which ions help neighboring strands lock into alignment so that matching genetic sequences can recognize one another more effectively.
Professor Alexey Kornyshev from Imperial College London and his collaborators originally proposed the model about twenty years ago, suggesting that salt ions surrounding DNA (搜索) could produce alternating patterns of electrical charge that help neighboring DNA molecules align much like two interlocking spiral staircases. Until now, directly observing the proposed mechanism had proved difficult.
"It was incredible to be able to directly visualize the long-hypothesized mechanism for the first time," said Dr. Thomas Catley, co-lead author from the School of Chemical Materials and Biological Engineering at the University of Sheffield. "The advanced imaging techniques at our disposal are allowing us to uncover these key DNA (搜索) interactions which have implications in many key cellular processes."
Dr. Victor Velasco-Berrelleza from the University of Sheffield, who performed the simulations, added: "Microscopy shows us what happens, but the simulations allow us to uncover the molecular mechanism behind it."
Sequence Hotspots and Cancer Relevance
DNA (搜索) does not pair equally well along every sequence. The researchers found that some stretches of DNA created much stronger contacts than others, producing distinct hotspots where two helices were especially likely to line up. The strength and location of these interactions varied depending on which ions were present.
Professor Agnes Noy, from the School of Physics, Engineering and Technology at the University of York (搜索), who co-led the research, said: "This discovery could help researchers identify regions of the genome specially involved in DNA (搜索) pairing. These regions may become particularly important when mutations disrupt normal cellular processes and contribute to cancer (搜索)."
The authors note that DNA (搜索) pairing has been observed in cancer (搜索)-related contexts, including processes associated with chromosome organization and genome regulation. Understanding how DNA strands recognize each other may therefore help researchers better understand mechanisms that contribute to disease.
Catley said the findings reinforce a growing understanding that DNA (搜索) is far more dynamic than many people realize. "One of the biggest implications from this work is the further evidence that DNA isn't just a static code—it is a highly dynamic system which is constantly reshaping and reorganizing," he explained.
Therapeutic and Biotechnology Implications
Beyond disease biology, the work may influence fields ranging from genetics to biotechnology. By revealing how DNA (搜索) molecules can self-organize without the assistance of proteins, the study offers a new framework for studying chromosome behavior and the three-dimensional arrangement of the genome.
"By showing how simple ions can act as anchors to align the DNA (搜索) helix, we not only shed more light on the mechanisms of cancer (搜索), but also aid the design of new therapeutic biotechnologies—for example DNA origamis for targeted drug delivery," Catley said.
Because some DNA (搜索) sequences can be programmed to interact more strongly than others, scientists may eventually be able to exploit these properties to build customized DNA structures for biotechnology applications.
The researchers acknowledge that practical applications are likely years away. "As with many fundamental discoveries, there is still a long way to go before we turn these findings into clinical results," Catley told Newsweek. "However, by directly seeing this long-proposed mechanism for the first time, we've added a crucial piece to the puzzle of how DNA (搜索) in our cells organizes itself, and where this might go wrong in cancer (搜索)."
Their results suggest that stable ion-mediated contacts can initiate DNA (搜索) pairing, while matching genetic sequences help maintain and extend those interactions over longer stretches of the genome—a molecular explanation for a phenomenon that has remained unresolved for more than 20 years.