Genetic Tailors: CTCF and Cohesin Shape the Genome During Evolution

Research into chromosome structure and organization is an old field that has seen some fascinating progress in recent years. Modern molecular methods that can describe the shape of chromosomes have begun to revolutionize our understanding of genome organization and the mechanisms that regulate gene activity. A picture is beginning to emerge of chromatin loops representing a widespread organizing principle of the chromatin fiber and the proteins cohesin and CCCTC-binding factor (CTCF) as key players anchoring such chromatin loops. Here we review our current understanding of the features of CTCF- and cohesin-mediated genome organization and how their evolution may have helped to shape genome structure.

TrendsThe development of Hi-C and advances in sequencing technology are resulting in chromatin contact maps with increasing resolution and providing information about chromosome organization at ever-finer scales.In the future, single-cell Hi-C methods may be integrated with RNA-seq data from the same cell, providing an unprecedented opportunity to explore structure–function events in individual cells.Genome-editing tools (CRISPR/Cas9) allow researchers to engineer specific deletions/insertions in the genome and then evaluate their roles in the structure and function of the genome.The addition of new species to the catalog of Hi-C-sequenced genomes represents an unparalleled opportunity to explore how, and possibly why, the organization of genomes has changed over the course of evolution.