Opening of cohesin’s SMC ring is essential for timely DNA replication and DNA loop formation

Sakata, Ryota; Niwa, Kyoma; Torre, Diego Ugarte La; Gu, Chenyang; Tahara, Eri; Takada, Shoji; Nishiyama, Tomoko

doi:10.1016/j.celrep.2021.108999

Cited by 12 publications

(14 citation statements)

References 61 publications

(82 reference statements)

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“…In the second setup, a loop extrusion assay using single DNA molecules was performed (Sakata et al , 2021; Kinoshita et al , 2022). In brief, holo(WT) and holo(H-dN) were labeled with Alexa Fluor 488 through a HaloTag (Fig EV1B) and subjected to the assay using U-shaped DNA.…”

Section: Resultsmentioning

confidence: 99%

“…In the second setup, a loop extrusion assay using single DNA molecules was performed (Sakata et al, 2021;Kinoshita et al, 2022). In brief, holo(WT) and holo(H- Taken together, these results show that deletion of the CAP-H N-tail affects the initial interactions with DNA, but not the core activity responsible for the expansion of DNA loops.…”

Section: Deletion Of the Cap-h N-tail Enables Condensin I To Assemble...mentioning

confidence: 91%

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Cell cycle-specific loading of condensin I is regulated by the N-terminal tail of its kleisin subunit

Hirano¹,

Tane²,

Shintomi³

et al. 2022

Preprint

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Condensin I is a pentameric protein complex that plays an essential role in mitotic chromosome assembly in eukaryotic cells. Although it has been shown that condensin I loading is mitosis-specific, it remains poorly understood how the robust cell cycle regulation of condensin I is achieved. Here we set up a panel of in vitro assays to demonstrate that cell cycle-specific loading of condensin I is regulated by the N-terminal tail (N-tail) of its kleisin subunit CAP-H. Deletion of the N-tail accelerates condensin I loading and chromosome assembly in Xenopus egg mitotic extracts. Phosphorylation-deficient and phosphorylation-mimetic mutations in the CAP-H N-tail decelerate and accelerate condensin I loading, respectively. Remarkably, deletion of the N-tail enables condensin I to assemble mitotic chromosome-like structures even in interphase extracts. Together with other extract-free functional assays in vitro, our results uncover one of the multilayered mechanisms that ensure cell cycle-specific loading of condensin I onto chromosomes.

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Section: Resultsmentioning

confidence: 99%

Section: Deletion Of the Cap-h N-tail Enables Condensin I To Assemble...mentioning

confidence: 91%

Cell cycle-specific loading of condensin I is regulated by the N-terminal tail of its kleisin subunit

Hirano¹,

Tane²,

Shintomi³

et al. 2022

Preprint

Self Cite

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show abstract

“…The possible role of transcription in shaping SMC complex-dependent genome architecture deserves further attention. Importantly, SMC variants can now be sought that separate topological loading and loop extrusion [ 73 ]. For example, yeast condensin's Ycg1 subunit plays a critical role in loop extrusion, while vertebrate condensin lacking its XCAP-G ortholog retains the ability to shape and individualize chromosomes [ 32 , 74 ].…”

Section: Discussionmentioning

confidence: 99%

SMC complexes: Lifting the lid on loop extrusion

Higashi¹,

Uhlmann²

2022

Current Opinion in Cell Biology

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“…The topology of DNA involved during loop extrusion has been a major point of discussion in recent years 1,[8][9][10] . Three possibilities have been proposed: i) topological binding, where the SMC ring opens to encircle the DNA, ii) pseudotopological loading, where a small nascent loop enters the SMC ring without opening, and where loop extrusion continues pseudotopologically by further extruding this inserted loop through the ring, iii) nontopological loading where the DNA does not enter the ring to extrude loop but instead binds at the outer interfaces of the SMC ring.…”

Section: Introductionmentioning

confidence: 99%

Can pseudotopological models for SMC-driven DNA loop extrusion explain the traversal of physical roadblocks bigger than the SMC ring size?

Pradhan

Barth

Kim

et al. 2022

Preprint

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DNA loop extrusion by structural-maintenance-of-chromosome (SMC) complexes has emerged as a primary organizing principle for chromosomes. The mechanism by which SMC motor proteins extrude DNA loops is still unresolved and much debated. The ring-like structure of SMC complexes prompted multiple models where the extruded DNA is topologically or pseudotopologically entrapped within the ring during loop extrusion. However, recent experiments showed the passage of roadblocks much bigger than the SMC ring size, suggesting a nontopological mechanism. Recently, attempts were made to reconcile the observed passage of large roadblocks with a pseudotopological mechanism. Here we examine the predictions of these pseudotopological models, and find that they are not consistent with some experimental data on SMC roadblock encounters. Particularly, these models predict the formation of two loops and that roadblocks will reside near the stem of the loop upon encounter - both in contrast to experimental observations. Overall, the experimental data reinforce the notion of a nontopological mechanism for extrusion of DNA.

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Opening of cohesin’s SMC ring is essential for timely DNA replication and DNA loop formation

Abstract: Highlights d ATP hydrolysis-driven SMC ring opening is essential for DNA replication d SMC ring opening is required for sister chromatid resolution and chromosome segregation d Closure of the SMC ring hinders translocation of cohesin on DNA and DNA loop extrusion

Cited by 12 publications

References 61 publications

Cell cycle-specific loading of condensin I is regulated by the N-terminal tail of its kleisin subunit

Cell cycle-specific loading of condensin I is regulated by the N-terminal tail of its kleisin subunit

SMC complexes: Lifting the lid on loop extrusion

Can pseudotopological models for SMC-driven DNA loop extrusion explain the traversal of physical roadblocks bigger than the SMC ring size?

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