Your body is truly amazing. Every cell inside of it is capable of organising massive messes of DNA into chromosomes as a cell prepares to divide. That DNA, when unravelled, can span more that two meters in length, but your body’s cells whip it into tidy bundles.
Courtesy: Delft University
We’ve long known that the body can do this. But how it accomplishes this biological feat is another thing. Now, researchers from Delft University in the Netherlands and EMBL Heidelberg in Germany have succeeded in actually catching the process on video, observing how DNA gets structured in real time.
A recording of DNA organising itself. Courtesy: Delft University
It’s pretty nuts. Researchers were able to observe that, when a cell is preparing to divide into two daughter cells, a single protein complex called condensin reels in long, messy, intermingled strands of DNA in the cell, then begins organising it into loops. Those loops are fundamentally important for chromosomes to form in cells. The loops compact a cell’s genome so that it can be distributed evenly to its two daughter cells. The work settles a long-standing scientific debate about how condensin works to organise the DNA in dividing cells.
“This is cool to see for the first time,” Eric Topol, a geneticist at Scripps Research Institute who was not associated with the research, told Gizmodo. “It’s a ‘seeing is believing’ story, clearing up what was debated and not really known until actually visualized. Amazing the kind of stuff we can get to see these days!”
Understanding the basics of DNA architecture, said Stephen Montgomery, a Stanford geneticist, has important implications for understanding many aspects of how our cells function and how genes are expressed in the body.
“Stretched out from a cell, DNA is about two meters long, so the process of its compaction and disentanglement is highly influential in gene regulation and maintenance of cellular state and homeostasis,” he said.
Some parts of the genome, for example, are packed more tightly than others and less strongly expressed. Others are looser, and more strongly expressed. The spatial organisation of DNA itself plays a crucial role in our biology.
An artist’s rendering of DNA organising itself. Courtesy: Delft University
Finding the answer to this long-standing mystery was as simple as just recording the process in action, Cees Dekker, the senior author on the study, told Gizmodo. Improved camera and lab technology finally made such a video possible.
“We have in my lab tools so that we can visualise a single DNA molecule, and that’s what we did,” Dekker said. “So we settled this debate that has been raging for decades. This is the way that DNA organizes itself. It loops and loops and loops.”
“Now we understand the key principle of how DNA organizes itself in ourselves through cell division,” he added. “That’s a pretty cool thing.”