Transport of DNA within cohesin involves clamping on top of engaged heads by Scc2 and entrapment within the ring by Scc3
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ABSTRACT:
PROVIDER: PRJNA658519 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR12491807.fastq.gz | Fastqsanger.gz | |||
| SRR12491808.fastq.gz | Fastqsanger.gz | |||
| SRR12491809.fastq.gz | Fastqsanger.gz | |||
| SRR12491810.fastq.gz | Fastqsanger.gz | |||
| SRR12491811.fastq.gz | Fastqsanger.gz |
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Project description:In addition to extruding DNA loops, cohesin entraps within its SMC-kleisin ring (S-K) individual DNAs during G1 and sister DNAs during S-phase. All three activities require related hook-shaped proteins called Scc2 and Scc3. Using thiol-specific crosslinking we provide rigorous proof of entrapment activity in vitro. Scc2 alone promotes entrapment of DNAs in the E-S and E-K compartments, between ATP-bound engaged heads and the SMC hinge and associated kleisin, respectively. This does not require ATP hydrolysis nor is it accompanied by entrapment within S-K rings, which is a slower process requiring Scc3. Cryo-EM reveals that DNAs transported into E-S/E-K compartments are “clamped” in a sub-compartment created by Scc2’s association with engaged heads whose coiled coils are folded around their elbow. We suggest that clamping may be a recurrent feature of cohesin complexes active in loop extrusion and that this conformation precedes the S-K entrapment required for sister chromatid cohesion.
2020-09-03 | GSE156616 | GEO
Project description:In addition to extruding DNA loops, cohesin entraps within its SMC-kleisin ring (S-K) individual DNAs during G1 and sister DNAs during S-phase. All three activities require related hook-shaped proteins called Scc2 and Scc3. Using thiol-specific crosslinking we provide rigorous proof of entrapment activity in vitro. Scc2 alone promotes entrapment of DNAs in the E-S and E-K compartments, between ATP-bound engaged heads and the SMC hinge and associated kleisin, respectively. This does not require ATP hydrolysis nor is it accompanied by entrapment within S-K rings, which is a slower process requiring Scc3. Cryo-EM reveals that DNAs transported into E-S/E-K compartments are 'clamped' in a sub-compartment created by Scc2's association with engaged heads whose coiled coils are folded around their elbow. We suggest that clamping may be a recurrent feature of cohesin complexes active in loop extrusion and that this conformation precedes the S-K entrapment required for sister chromatid cohesion.
| S-EPMC7492086 | biostudies-literature
Project description:The ring-shaped cohesin complex is the key player in sister chromatid cohesion, DNA repair, and gene transcription. The loading of cohesin to chromosomes requires the loader Scc2 and is regulated by ATP. This process is also hindered by Smc3 acetylation. However, the molecular mechanism behind this inhibition remains mysterious. Here we identify a novel configuration of Scc2 with pre-engaged cohesin and reveal dynamic conformations of the cohesin/Scc2 complex in the loading reaction. We demonstrate that Smc3 acetylation blocks the association of Scc2 with pre-engaged cohesin by impairing the interaction of Scc2 with Smc3’s head. Lastly, we show that ATP binding induces the cohesin/Scc2 complex to clamp DNA by promoting the interaction between Scc2 and Smc3 coiled-coil. Our results illuminate a dynamic reconfiguration of the cohesin/Scc2 complex during loading and indicate how Smc3 acetylation and ATP regulate this process.
2023-08-16 | GSE217833 | GEO
Project description:The ring-like cohesin complex plays an essential role in chromosome segregation, organization, and double-strand break repair through its ability to bring two DNA double helices together. Scc2 (NIPBL in humans) together with Scc4 function as the loader of cohesin onto chromosomes. Chromatin adapters such as the RSC complex facilitate localization of the Scc2-Scc4 cohesin loader. Here we identify a broad range of Scc2- chromatin protein interactions that are evolutionarily conserved and reveal a role for one complex, Mediator, in recruitment of the cohesin loader. We identified budding yeast Med14, a subunit of the Mediator complex, as a high copy suppressor of poor growth in Scc2 mutant strains. Physical and genetic interactions between Scc2 and Mediator are functionally substantiated in direct recruitment and cohesion assays. Depletion of Med14 results in defective sister chromatid cohesion and decreased binding of Scc2 at RNA Pol II transcribed genes. Previous work has suggested that Mediator, Nipbl, and cohesin connect enhancers and promoters of active mammalian genes. Our studies suggest an evolutionarily conserved fundamental role for Mediator in direct recruitment of Scc2 to RNA pol II transcribed genes. We identified two mutations in the evolutionarily conserved HEAT domain of SCC2 that result in significantly reduced growth, scc2R787G and scc2G1242V. This experiment uses RNA-Seq analysis to study the effect of these mutations on gene expression.
2022-05-25 | GSE201191 | GEO
Project description:The ring-like cohesin complex plays an essential role in chromosome segregation, organization, and double-strand break repair through its ability to bring two DNA double helices together. Scc2 (NIPBL in humans) together with Scc4 function as the loader of cohesin onto chromosomes. Chromatin adapters such as the RSC complex facilitate localization of the Scc2-Scc4 cohesin loader. Here we identify a broad range of Scc2- chromatin protein interactions that are evolutionarily conserved and reveal a role for one complex, Mediator, in recruitment of the cohesin loader. We identified budding yeast Med14, a subunit of the Mediator complex, as a high copy suppressor of poor growth in Scc2 mutant strains. Physical and genetic interactions between Scc2 and Mediator are functionally substantiated in direct recruitment and cohesion assays. Depletion of Med14 results in defective sister chromatid cohesion and decreased binding of Scc2 at RNA Pol II transcribed genes. Previous work has suggested that Mediator, Nipbl, and cohesin connect enhancers and promoters of active mammalian genes. Our studies suggest an evolutionarily conserved fundamental role for Mediator in direct recruitment of Scc2 to RNA pol II transcribed genes. We identified two mutations in the evolutionarily conserved HEAT domain of SCC2 that result in significantly reduced growth, scc2R787G and scc2G1242V. This experiment uses RNA-Seq analysis to study the effect of these mutations on gene expression.
2022-05-25 | GSE201192 | GEO
Project description:The evolutionarily conserved cohesin complex is crucial for holding sister chromatids together from the time of DNA replication until their segregation during the metaphase to anaphase transition. Human diseases associated with with mutations in the cohesin network are termed "cohesinopathies". Scc2 is required for loading cohesin onto DNA prior to DNA replication. Cornelia de Lange syndrome (CdLS), a developmental disorder characterized by growth and intellectual impairment is caused by mutations in Scc2. How mutations in Scc2 gives rise to these developmental defects is currently unknown, as overt defects in chromosome segregation are not observed in CdLS patients. One hypothesis is that, reduced binding of Scc2 causes gene misregulation. To further explore this idea ChIP-seq was performed using an scc2-4 mutant. We observed from the analysis, we observe reduce binding of Scc2 to Pol II transcribed genes (snoRNAs, ribosomal protein genes) and pol II transcribed genes (tRNAs). Studies are currently underway to examine the biological implications of this observation.
2015-06-16 | GSE55357 | GEO
Project description:The evolutionarily conserved cohesin complex is crucial for holding sister chromatids together from the time of DNA replication until their segregation during the metaphase to anaphase transition. Human diseases associated with with mutations in the cohesin network are termed "cohesinopathies". Scc2 is required for loading cohesin onto DNA prior to DNA replication. Cornelia de Lange syndrome (CdLS), a developmental disorder characterized by growth and intellectual impairment is caused by mutations in Scc2. How mutations in Scc2 gives rise to these developmental defects is currently unknown, as overt defects in chromosome segregation are not observed in CdLS patients. One hypothesis is that, reduced binding of Scc2 causes gene misregulation. To further explore this idea ChIP-seq was performed using an scc2-4 mutant. We observed from the analysis, we observe reduce binding of Scc2 to Pol II transcribed genes (snoRNAs, ribosomal protein genes) and pol II transcribed genes (tRNAs). Studies are currently underway to examine the biological implications of this observation. Examining genome-wide binding of scc2-4 mutant
2015-06-16 | E-GEOD-55357 | biostudies-arrayexpress
Project description:The functions of cohesin are central to genome integrity, chromosome organization, and transcription regulation through its prevention of premature sister-chromatid separation and the formation of DNA loops. The loading of cohesin onto chromatin depends on the Scc2-Scc4 complex, however, little is known about how it stimulates the cohesin loading activity. Here we determine the large “hook” structure of Scc2 responsible for catalyzing cohesin loading. We identify key Scc2 surfaces that are crucial for DNA binding and for cohesin loading in vivo. Using previously determined structures and modeling, we derive a pseudo-atomic structure of the full-length Scc2-Scc4 complex. Finally, our crosslinking and electron microscopy analyses reveal that Scc2-Scc4 utilizes its modular structure to make multiple contacts with a folded cohesin at an interface created by the cohesin head-hinge interaction.
2017-01-11 | PXD004692 | Pride
Project description:The evolutionarily conserved cohesin complex is crucial for holding sister chromatids together from the time of DNA replication until their segregation during the metaphase to anaphase transition. Human diseases associated with with mutations in the cohesin network are termed "cohesinopathies". Scc2 is required for loading cohesin onto DNA prior to DNA replication. Cornelia de Lange syndrome (CdLS), a developmental disorder characterized by growth and intellectual impairment is caused by mutations in Scc2. How mutations in Scc2 gives rise to these developmental defects is currently unknown, as overt defects in chromosome segregation are not observed in CdLS patients.This has led to the hypothesis that developmental disorders in CdLS patients are a result of dysregulated gene expression. To examine the transcriptional program of Scc2 mutants called scc2-4, RNA sequencing was performed. Analysis of gene expression program shows upregulation of genes involved in ribosome biogenesis and downregulation of genes needed for oxidative phosphorylation. Studies are currently underway to investigate how scc2-4 mutation causes gene misregulation. The answer(s) could provide insight into the molecular etiology of CdLS.
2015-06-16 | GSE55316 | GEO
Project description:Cohesin’s association with and translocation along chromosomal DNAs depend on an ATP hydrolysis cycle driving the association and subsequent release of DNA. This involves DNA being ‘clamped’ by Scc2 and ATP-dependent engagement of cohesin’s Smc1 and Smc3 head domains. Scc2’s replacement by Pds5 abrogates cohesin’s ATPase and has an important role in halting DNA loop extrusion. The ATPase domains of all SMC proteins are separated from their hinge dimerisation domains by 50 nm long coiled coils, which have been observed to zip up along their entire length and fold around an elbow, thereby greatly shortening the distance between hinges and ATPase heads. Whether folding exists in vivo or has any physiological importance is not known. We present here a cryo-EM structure of the apo form of cohesin that reveals the structure of folded and zipped up coils in unprecedented detail and shows that Scc2 can associate with Smc1’s ATPase head even when it is fully disengaged from that of Smc3. Using cysteine-specific cross-linking, we show that cohesin’s coiled coils are frequently folded in vivo, including when cohesin holds sister chromatids together. Moreover, we describe a mutation (SMC1D588Y) within Smc1’s hinge that alters how Scc2 and Pds5 interact with Smc1’s hinge and that enables Scc2 to support loading in the absence of its normal partner Scc4. The mutant phenotype of loading without Scc4 is only explicable if loading depends on an association between Scc2/4 and cohesin’s hinge, which in turn requires coiled coil folding.
2021-07-21 | GSE167318 | GEO