The condensation of hundreds of megabase-pair-long human chromosomes in a small nuclear volume is a spectacular biological phenomenon. It is thought that the process is driven by the formation of chromosome loops, which are driven by ATP-consuming motors. An analytically solvable model for loop extrusion (LE) is described, which was motivated by real-time imaging experiments. Theory suggests that the motors undergo a large conformational change, induced by ATP binding, bringing distant parts of the motor to proximity by a scrunching mechanism, like that proposed in DNA bubble formation during bacterial transcription. Extension of the theory to multiple motors in conjunction with a method that uses Hi-C data show that mitotic structures are characterized by random helical perversion.
About Dave Thirumalai
Dave Thirumalai is the holder of the Collie-Welch Regents Chair at The University of Texas at Austin. His current research interest lies in understanding the physics of chromosome folding with particular focus on the role motors play in affecting the structures of mitotic chromosomes. In addition, he is also developing theoretical and computational methods to describe collective cell migration, which have potential applications to the physics of cancer.
Sponsored by the Center for Physical Genomics and Engineering, the Cancer and Physical Sciences Program at the Robert H. Lurie Comprehensive Cancer Center, and NIH Grants T32GM142604 and U54CA268084