Description:

The chromosomes of cells are based on very long DNA molecules that must be replicated, disentangled and physically separated to allow successful cell division. Our group uses biophysical approaches to study chromosome structure and dynamics. A key feature of chromosome organization is the role of active chromosome loop formation, or "loop extrusion" as a mechanism underlying chromosome compaction, individualization, and segregation, as well as maintenance of regulatory chromatin loops. I will discuss experiments on SMC complexes (condensin, cohesin and SMC5/6 in eukaryotes), currently thought to be the loop-extruding elements, and how those experiments inform us on the mechanisms of these novel chromatin-organizing motors. For whole chromosomes, compaction via formation of tightly packed loops is combined with chromatin-chromatin interactions to achieve separation of chromosomes during cell division.  I will also discuss our recent studies of the mechanics of the cell nucleus between cell divisions and the role of the nuclear envelope and chromatin in controlling nuclear mechanics.

John Marko, Professor / Joint with Molecular Biosciences, Northwestern University