Using DNA to take snapshots of cells

Science magazine takes focus on a new form of microscopy, using DNA like a microscope to look inside cells:

To make the DNA microscope, postdoc Joshua Weinstein of the Broad Institute of in Cambridge, Massachusetts, and colleagues started with a group of cells in a culture dish. By creating DNA versions of the RNA molecules in the cells, they produced a large number of DNA molecules they could track. They then added tags—short pieces of DNA—that latched onto these DNA duplicates. Next, the scientists mixed in chemicals that produce multiple copies of these tags and the DNA molecules they connect to. As these copies built up, they started to drift away from their original location. When two wandering DNA molecules ran into each other, they linked up and spawned a unique DNA label that marked the encounter.

These labels are crucial for capturing a DNA image of the cells. If two DNA molecules start out close to each other, their diffusing copies will hook up frequently and produce more labels than two DNA molecules that start out farther apart. To count the labels, the researchers grind up the cells and analyze the DNA they contain. A computer algorithm can then infer the original positions of the DNA molecules to generate an image.

…DNA microscopy can do some things optical microscopy can’t. For instance, optical microscopy often can’t distinguish among cells with DNA differences, such as tumor cells with specific mutations or immune cells, which are often genetically unique after shuffling their DNA. Weinstein says DNA microscopy may help improve certain cancer treatments by identifying immune cells that can attack tumors.

You can read the original research in Cell here.