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Cohesin-mediated DNA loop extrusion resolves sister chromatids in G2 phase
Paul Batty1,2, Christoph Ch Langer1, Zsuzsanna Takács1
1Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.
The EMBO Journal
|June 26, 2023
Summary
Sister chromatids resolve early in interphase due to cohesin
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Genetic information is stored in highly folded DNA.
- Replicated DNA forms intertwined sister chromatids that must separate for cell division.
- Mechanisms for sister chromatid resolution before mitosis are poorly understood.
Purpose of the Study:
- To investigate the chromosome-intrinsic mechanics of sister chromatid resolution during interphase.
- To determine the roles of cohesin and condensins in pre-mitotic sister chromatid separation.
Main Methods:
- Studied human cells during interphase.
- Assessed the impact of cohesin and condensin activity on sister chromatid resolution.
- Manipulated cohesin's looping capability.
Main Results:
- Sister chromatids resolve extensively during interphase, independent of condensins.
- Enhanced cohesin looping activity significantly increases interphase sister chromatid resolution.
- Cohesin's loop-extruding activity drives early resolution, even with arm cohesion present.
Conclusions:
- DNA loop extrusion by cohesin is a key mechanism for resolving sister chromatids during interphase.
- This process is not mitosis-specific and highlights a conserved genome segregation mechanism.
- Cohesin's role in resolution suggests a shared function across Structural Maintenance of Chromosomes (SMC) complexes in all life.
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