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Depletion of the cohesin-associated protein Wapl in mice is shown to increase the residence time of cohesin on DNA, which leads to clustering of cohesin in axial structures, and causes chromatin condensation in interphase chromosomes; the findings suggest that cohesin could have an architectural role in interphase chromosome organization.

The distribution of cohesin in the mouse genome depends on CTCF, transcription and the cohesin release factor Wapl.

Cohesin functions must be tightly regulated. Here Prusén Mota et al. show that the cohesin regulator SORORIN is conserved beyond the animal kingdom and they provide the first organismal in vivo evidence that SORORIN antagonizes WAPL.

Single-nucleus Hi-C of embryos, polymer simulations and single-molecule imaging collectively reveal that MCM complexes influence genome folding and gene expression by impeding DNA loop extrusion.

V gene recombination at the immunoglobulin heavy chain locus (Igh) is facilitated by extended loop extrusion. In this study, the authors find that, unlike Igh, the κ light chain locus does not involve extended loop extrusion but instead involves multiple, short-range loops for V gene combination.

Modified chromosome conformation capture (Hi-C) technology is used to characterize the interactions between sister chromatids, despite their identical DNA sequences.

Pax5 regulates contraction of the immunoglobulin heavy chain (Igh) locus—an essential step in V(D)J recombination—by promoting chromatin loop extrusion via repression of Wapl expression.

When a cell divides, each daughter cell inherits a complete set of chromosomes. A sophisticated inhibitory mechanism delays chromosome segregation and cell division until everything is in its place.

APC/C is an E3 ligase complex of ~1.5 MDa that regulates cell division. APC/C^CDH1 is inhibited during interphase by EMI1. Now, NMR spectroscopy, electron microscopy and enzymology analyses are integrated, revealing that EMI1's 143-residue C-terminal ___domain binds distinct regions of APC/C^CDH1 to block the substrate-binding site and inhibit ubiquitin-chain elongation.

Activation of the anaphase-promoting complex/cyclosome (APC/C) depends on disassembly of the mitotic checkpoint complex (MCC), which has been proposed to require CDC20 autoubiquitylation. A new study involving reconstituted recombinant human APC/C supports the view that the APC15 subunit of APC/C localizes near the MCC binding site and mediates CDC20 autoubiquitylation, thereby promoting MCC disassembly.

CTCF is sufficient to block loop extruding cohesin in a DNA tension dependent manner, and induces loop extrusion direction switching and loop shrinkage.

Cohesin protein complex is a molecular machine that extrudes DNA loops. Here, authors show that bending of the molecule’s long coiled coils is driven by thermal fluctuations and engagement of ATPase domains uses ATP energy to generate strong force.

Mass photometry is a label-free optical approach capable of detecting, imaging and accurately measuring the mass of single biomolecules in solution. Here, the authors demonstrate the potential of mass photometry for quantitatively characterizing sample heterogeneity of purified protein complexes with implications for structural studies specifically and in vitro studies more generally.

The anaphase-promoting complex/cyclosome (APC/C) is key to cell cycle regulation and is an E3 ubiquitin ligase. The overall shape of the substrate-free complex has previously been determined in various species. Budding yeast and human APC/Cs are now analyzed by EM structural and biochemical approaches to assess the substrate-binding site and elucidate the relative positioning of Doc1, a factor known to promote processive substrate ubiquitylation.

Cohesin is a ring-shaped protein complex that structures chromatin and mediates sister chromatid cohesion. Here the authors rigidify cohesin using engineered Smc1 and Smc3 and generated 3D models showing how Pds5B forms an integral part of the cohesin ring.

The anaphase promoting complex/cyclosome (APC/C) is the largest known complex that catalyses ubiquitylation reactions and has key functions in the eukaryotic cell cycle. Recent studies have shed light on how APC/C activity is controlled and how it recognizes a multitude of substrates.

The cell cycle regulatory E3 ligase APC/C cooperates with UBE2C to prime substrates with ubiquitin and UBE2S to extend the ubiquitin chains. Careful analysis reveals that binding of the UBE2S to APC/C accelerates the rate-limiting step of APC/C–UBE2C.

High-throughput microscopy combined with gene silencing by RNA interference is a powerful method for studying gene function. Here, a genome-wide method is presented for phenotypic screening of each of the ∼21,000 human protein-coding genes, using two-day imaging of dividing cells with fluorescently labelled chromosomes. The method enabled the identification of hundreds of genes involved in biological functions such as cell division, migration and survival.

The anaphase-promoting complex (APC) initiates exit from mitosis by ubiquitinating A- and B-type cyclins, the activating subunits of cyclin-dependent kinase 1 (Cdk1). Subsequently, the APC has to be inactivated to allow the re-accumulation of mitotic cyclins in the next cell cycle. A newly identified inhibitor of the APC, called Emi1 in vertebrates and Rca1 in Drosophila melanogaster, may have an important function in inactivating the APC during interphase.

ProteoPlex optimizes buffer conditions for the isolation and purification of macromolecular complexes. The concurrent complex stabilization is beneficial for structure determination using X-ray crystallography or cryo-electron microscopy.

The anaphase-promoting complex/cyclosome (APC/C) is a ubiquitin ligase that controls cell-cycle progression by targeting proteins for destruction by the 26S proteasome. The APC/C is active throughout late mitosis and G1 phase but APC/C substrates are degraded in a specific order. A recent study provides insights into how ordered turnover of substrates is achieved.

Quantitative live-cell imaging provides a dynamic protein atlas of mitosis.

Massively parallel but cost-effective testing is essential to monitor the spread of pathogenic agents. Here the authors present SARSseq, which uses a dual indexing strategy in a multiplexed RT-PCR reaction to diagnose SARS-CoV-2 at scale.

Chromatin loops are proposed to be formed through loop extrusion by structural maintenance of chromosomes (SMC) complexes. Recent studies have shown that the SMC complexes condensin and cohesin are indeed able to extrude DNA, and caused a paradigm shift in our understanding of genome organization and the cellular functions of SMC complexes.

An RNAi screen of protein phosphatases identifies PP2A–B55α as the main mitotic exit phosphatase in human cells. After mitosis, PP2A–B55α depletion delays the reassembly of the nuclear envelope and Golgi and the decondensation of chromatin.