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Synthetic Condensates and Cell-Like Architectures from Amphiphilic DNA Nanostructures
Published on: May 31, 2024
The cohesin ring concatenates sister DNA molecules
Christian H Haering1, Ana-Maria Farcas, Prakash Arumugam
1University of Oxford, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK.
Nature
|July 4, 2008
Summary
Cohesin, a protein complex crucial for cell division, forms a ring that traps sister DNA molecules. This study chemically closed the cohesin ring, confirming its role in holding DNA strands together during mitosis.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Sister chromatid cohesion is vital for accurate chromosome segregation during mitosis.
- The cohesin complex, comprising Scc1, Smc1, and Smc3 subunits, forms a tripartite ring structure.
- The ring entrapment model proposes that cohesin encircles sister DNA molecules to maintain cohesion.
Purpose of the Study:
- To experimentally validate the ring entrapment model of cohesin function.
- To investigate the structural mechanism by which cohesin mediates sister chromatid cohesion.
Main Methods:
- Site-specific crosslinking was employed to create covalently closed cohesin rings.
- Chemical connections were introduced at the interfaces between Scc1, Smc1, and Smc3 subunits.
- The stability and DNA-binding properties of the modified cohesin rings were assessed.
Main Results:
- Covalently closed cohesin rings were successfully generated.
- These modified cohesin structures formed dimeric DNA-cohesin complexes.
- The DNA-cohesin complexes exhibited resistance to protein denaturation, supporting the entrapment model.
Conclusions:
- Cohesin rings physically entrap individual sister minichromosome DNA molecules.
- The study provides direct evidence for the ring entrapment model of sister chromatid cohesion.
- This mechanism is essential for maintaining genomic stability during cell division.
Related Concept Videos
02:20Cohesins
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 homologous...
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 homologous...
02:20Cohesins
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 homologous...
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 homologous...
02:15Condensins
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...
02:15Condensins
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...
02:17Separation of Sister Chromatids
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...
02:17Separation of Sister Chromatids
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...