The biology and polymer physics underlying large ‐scale chromosome organization

Chromosome large‐scale organization is a beautiful example of the interplay between physics and biology. DNA molecules are polymers and thus belong to the class of molecules for which physicists have developed models and formulated testable hypotheses to understand their arrangement and dynamic properties in solution, based on the principles of polymer physics. Biologists documented and discovered the biochemical basis for the structure, function and dynamic spatial organization of chromosomes in cells. The underlying principles of chromosome organization have recently been revealed in unprecedented detail using high‐resolution chromosome capture technology that can simultaneously detect chromosome contact sites throughout the genome. These independent lines of investigation have now converged on a model in which DNA loops, generated by the loop extrusion mechanism, are the basic organizational and functional units of the chromosome.

Deciphering the basic principles of chromosome organization from the separate perspectives of biology and polymer physics has undergone paradigm shifts over many decades, but these 2 fields have now converged on a model that explains the formation and positioning of loops and the loopy globule organization of chromosomes in interphase eukaryotic cells. According to this model, the cohesin complex binds to DNA and extrudes a loop of DNA until it reaches CTCF proteins bound to convergently positioned binding sites.

Source: Traffic - December 3, 2017 Category: Research Authors: Shelley Sazer, Helmut Schiessel Tags: REVIEW Source Type: research