A cohesin-regulated tug-of-war inside chromosomes

Cohesin, a ring-shaped protein complex, tethers the two DNA copies contained in each replicated chromosome such that they can be properly moved during cell division. A subset of cohesin complexes, known for its ability to extrude DNA loops, also facilitates the separation of duplicated DNA molecules, a new study by the Gerlich lab at IMBA - Institute of Molecular Biotechnology of the Austrian Academy of Sciences - shows. These findings support the notion that DNA loop extrusion is an evolutionarily conserved mechanism, promoting the segregation of replicated genomes into daughter cells.

Sister chromatid resolution by cohesin. One sister chromatid in each replicated chromosome was stained by the nucleotide analog f-ara-EdU (green) and all DNA was counterstained by DAPI. The residence time of cohesin was increased to enlarge loops, resulting in extensive resolution of sister chromatids, resembling unperturbed cells in mitosis. ©Batty/Gerlich/EMBO J

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