MIT researchers reshape DNA folding

DNA isn’t just a string of genes with labels on it. It’s a twisted physical object, and every time a cell reads one gene, that reading process changes the twist nearby. MIT researchers just showed that this mechanical effect is strong enough to reshape how neighboring genes behave in human cells — and, crucially, that you can design around it. That matters because synthetic biology usually treats genes like modular parts. This work says the layout itself is part of the program. ### What actually changed? The new result is an experimental one. Katie Galloway’s lab at MIT, led on this paper by Christopher Johnstone, tested whether the order and orientation of adjacent genes — what they call “gene syntax” — can systematically change gene expression by altering DNA supercoiling as transcription happens. The paper appeared in *Science* on April 30, 2026. ### What is the physical trick here? When RNA polymerase transcribes a gene, it has to pry open the DNA helix and move along it. That motion doesn’t stay local. It changes the twisting of DNA around the active gene — loosening DNA on one side and tightening it on the other. MIT’s experiments show that this twist pattern changes how easy it is for polymerase to start transcribing neighboring genes. Upstream neighbors tend to get a boost. Downstream neighbors tend to get suppressed. Basically, one active gene creates a mechanical bias for the genes next to it. ### Why does gene order matter so much? Because “neighboring genes” is not one thing. The team looked at three layouts: tandem, where two genes point the same way; divergent, where they point away from each other; and convergent, where they point toward each other. Those layouts feel abstract, but they decide where positive and negative supercoiling piles up. So the same two genes can help each other, interfere with each other, or alternate their output depending on how they’re arranged on the DNA. The sequence still matters — but the map matters too. ### Why is that a big deal for synthetic biology? Most synthetic gene circuits are built as if each component mainly talks through biochemistry — promoters, repressors, transcription factors, feedback loops. This study adds another control layer: the mechanics of the DNA strand itself. If you ignore that layer, a circuit can behave unpredictably. If you use it on purpose, you can make circuits that amplify output, damp it, or switch between states more cleanly. That is a big upgrade for anyone trying to engineer cells to do reliable work. ### Didn’t people already know DNA folding affects genes? Yes — but mostly at the level of chromatin, loops, and 3D genome architecture. The sharper point here is that ordinary transcription of one gene can directly tune its immediate neighbors through local supercoiling, and that this can be used as a design rule. MIT had modeled the idea back in 2022. The new paper shows it in cells and turns it into something engineers can use, not just something biologists should keep in mind. ### Is this “switching genes on and off” in a therapy sense? Not really — at least not yet. This is much more of a design and control result than a ready-made medical technology. The near-term use is building better synthetic circuits and understanding why neighboring genes can couple in surprising ways. That could eventually matter for cell programming and disease models, but the paper is not a gene therapy platform announcement. The catch is that biology is messy, and effects that are clear in engineered systems still have to prove themselves across different cell types and genomic contexts. ### So what’s the cleanest way to think about it? Think of DNA less like a text file and more like a spring-loaded cable. Reading one section slightly twists the cable, and that changes how easy it is to read the next section. MIT’s contribution is showing that this isn’t just a nuisance. It’s a usable engineering parameter. ### Bottom line? The headline isn’t that MIT learned to arbitrarily refold the whole genome. It’s subtler and, in some ways, more useful: gene activity mechanically reshapes nearby DNA, and researchers can exploit that by choosing gene order and orientation carefully. For synthetic biology, that turns DNA layout from background detail into a real control knob.