Related Experiment Video
Updated: Jun 9, 2025
07:55
Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae
Published on: September 11, 2022
1.8K
Cohesin complex oligomerization maintains end-tethering at DNA double-strand breaks.
Jamie Phipps1,2, Mathias Toulouze1,2, Cécile Ducrot1,2
1UMR Stabilité Génétique Cellules Souches et Radiations, Université Paris Cité, INSERM, CEA, Fontenay-aux-Roses, France.
Nature Cell Biology
|November 1, 2024
Summary
Cohesin
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Genome stability relies on efficient DNA double-strand break (DSB) repair.
- Timely DSB repair requires keeping broken DNA ends tethered.
- Two DSB end-tethering pathways exist in Saccharomyces cerevisiae: the MRX complex and an Exo1-dependent pathway with unknown bridging proteins.
Purpose of the Study:
- To identify the bridging proteins involved in the Exo1-dependent DSB end-tethering pathway.
- To elucidate the role of cohesin oligomerization in DSB repair.
Main Methods:
- Utilized Saccharomyces cerevisiae as a model organism.
- Employed microscopy-based microfluidic experiments.
- Investigated the function of cohesin, its loader, and Smc5/6 in conjunction with Exo1.
Main Results:
- Cohesin, its loader, and Smc5/6 were identified as key players in tethering DSB ends with Exo1.
- Cohesin impaired in oligomerization failed to tether DSB ends, highlighting the importance of this function.
- Cohesin was shown to play a direct role in DSB repair by ensuring end-tethering, beyond its role in sister chromatid cohesion.
Conclusions:
- Cohesin's oligomerization is essential for preventing DSB end-separation and promoting repair.
- This study reveals a novel mechanism for cohesin in safeguarding genome integrity through DSB end-tethering.
Related Concept Videos
02:20Cohesins
4.4K
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of...
4.4K
02:31Homologous Recombination
50.2K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
50.2K
02:04Fixing Double-strand Breaks
12.3K
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
12.3K
02:17Separation of Sister Chromatids
3.6K
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
3.6K
02:15Condensins
3.4K
Condensins are large protein complexes that use ATP to fuel the assembly of chromosomes during mitosis. They transform the tangled, shapeless mass of post-interphase DNA into individualized chromosomes by compacting, organizing, and segregating chromosomal DNA.
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
3.4K
02:57Attachment of Sister Chromatids
3.2K
As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules. Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall...
3.2K