Congratulations to Viraat on his new preprint in collaboration with Nick Aboreden and Gerd Blobel at UPenn, Ed Banigan and Leonid Mirny here at MIT and also to James Jusuf here in the lab.

Previously, it was thought that all 3D genome structure is erased during mitosis and must be re-established as cells enter G1 phase. Using RCMC to generate high-res 3D genome maps at the mitosis-to-G1 transition, we show for the first time that this is not the case.

We unexpected observe strong microcompartments that are present already in prometaphase and further strengthen in ana/telophase.

Using 3D polymer modeling, we show that chromosome compaction is a strong regulator of compartment strength and that the 2-3-fold higher compaction of mitotic chromosomes largely explains the existence of microcompartments in mitotic chromosomes.

Check out the full preprint here.

See also a related and co-submitted preprint from Job Dekker's lab here.

Below: a GIF showing how 3D genome structure changes from mitosis to G1 at the Klf1 locus, comparing RCMC to Hi-C.