1
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Zhao Y, Ren L, Zhao T, You H, Miao Y, Liu H, Cao L, Wang B, Shen Y, Li Y, Tang D, Cheng Z. SCC3 is an axial element essential for homologous chromosome pairing and synapsis. eLife 2024; 13:RP94180. [PMID: 38864853 PMCID: PMC11168746 DOI: 10.7554/elife.94180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024] Open
Abstract
Cohesin is a multi-subunit protein that plays a pivotal role in holding sister chromatids together during cell division. Sister chromatid cohesion 3 (SCC3), constituents of cohesin complex, is highly conserved from yeast to mammals. Since the deletion of individual cohesin subunit always causes lethality, it is difficult to dissect its biological function in both mitosis and meiosis. Here, we obtained scc3 weak mutants using CRISPR-Cas9 system to explore its function during rice mitosis and meiosis. The scc3 weak mutants displayed obvious vegetative defects and complete sterility, underscoring the essential roles of SCC3 in both mitosis and meiosis. SCC3 is localized on chromatin from interphase to prometaphase in mitosis. However, in meiosis, SCC3 acts as an axial element during early prophase I and subsequently situates onto centromeric regions following the disassembly of the synaptonemal complex. The loading of SCC3 onto meiotic chromosomes depends on REC8. scc3 shows severe defects in homologous pairing and synapsis. Consequently, SCC3 functions as an axial element that is essential for maintaining homologous chromosome pairing and synapsis during meiosis.
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Affiliation(s)
- Yangzi Zhao
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhouChina
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Lijun Ren
- College of Horticulture Science and Engineering, Shandong Agricultural UniversityShandongChina
| | - Tingting Zhao
- College of Horticulture Science and Engineering, Shandong Agricultural UniversityShandongChina
| | - Hanli You
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhouChina
| | - Yongjie Miao
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhouChina
| | - Huixin Liu
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Lei Cao
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Bingxin Wang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Yi Shen
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Yafei Li
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Ding Tang
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of SciencesBeijingChina
| | - Zhukuan Cheng
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhouChina
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2
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Prusén Mota I, Galova M, Schleiffer A, Nguyen TT, Kovacikova I, Farias Saad C, Litos G, Nishiyama T, Gregan J, Peters JM, Schlögelhofer P. Sororin is an evolutionary conserved antagonist of WAPL. Nat Commun 2024; 15:4729. [PMID: 38830897 PMCID: PMC11148194 DOI: 10.1038/s41467-024-49178-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 05/26/2024] [Indexed: 06/05/2024] Open
Abstract
Cohesin mediates sister chromatid cohesion to enable chromosome segregation and DNA damage repair. To perform these functions, cohesin needs to be protected from WAPL, which otherwise releases cohesin from DNA. It has been proposed that cohesin is protected from WAPL by SORORIN. However, in vivo evidence for this antagonism is missing and SORORIN is only known to exist in vertebrates and insects. It is therefore unknown how important and widespread SORORIN's functions are. Here we report the identification of SORORIN orthologs in Schizosaccharomyces pombe (Sor1) and Arabidopsis thaliana (AtSORORIN). sor1Δ mutants display cohesion defects, which are partially alleviated by wpl1Δ. Atsororin mutant plants display dwarfism, tissue specific cohesion defects and chromosome mis-segregation. Furthermore, Atsororin mutant plants are sterile and separate sister chromatids prematurely at anaphase I. The somatic, but not the meiotic deficiencies can be alleviated by loss of WAPL. These results provide in vivo evidence for SORORIN antagonizing WAPL, reveal that SORORIN is present in organisms beyond the animal kingdom and indicate that it has acquired tissue specific functions in plants.
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Affiliation(s)
- Ignacio Prusén Mota
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and the Medical University of Vienna, Vienna, Austria
| | - Marta Galova
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Tan-Trung Nguyen
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria
| | - Ines Kovacikova
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria
| | - Carolina Farias Saad
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and the Medical University of Vienna, Vienna, Austria
| | - Gabriele Litos
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Tomoko Nishiyama
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Juraj Gregan
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria.
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Tulln an der Donau, Austria.
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
| | - Peter Schlögelhofer
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria.
- University of Vienna, Center for Molecular Biology, Department of Chromosome Biology, Vienna, Austria.
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3
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Pezic D, Weeks S, Varsally W, Dewari PS, Pollard S, Branco MR, Hadjur S. The N-terminus of Stag1 is required to repress the 2C program by maintaining rRNA expression and nucleolar integrity. Stem Cell Reports 2023; 18:2154-2173. [PMID: 37802073 PMCID: PMC10679541 DOI: 10.1016/j.stemcr.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023] Open
Abstract
Our understanding of how STAG proteins contribute to cell identity and disease have largely been studied from the perspective of chromosome topology and protein-coding gene expression. Here, we show that STAG1 is the dominant paralog in mouse embryonic stem cells (mESCs) and is required for pluripotency. mESCs express a wide diversity of naturally occurring Stag1 isoforms, resulting in complex regulation of both the levels of STAG paralogs and the proportion of their unique terminal ends. Skewing the balance of these isoforms impacts cell identity. We define a novel role for STAG1, in particular its N-terminus, in regulating repeat expression, nucleolar integrity, and repression of the two-cell (2C) state to maintain mESC identity. Our results move beyond protein-coding gene regulation via chromatin loops to new roles for STAG1 in nucleolar structure and function, and offer fresh perspectives on how STAG proteins, known to be cancer targets, contribute to cell identity and disease.
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Affiliation(s)
- Dubravka Pezic
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Samuel Weeks
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Wazeer Varsally
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Pooran S Dewari
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Steven Pollard
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, UK
| | - Suzana Hadjur
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK.
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4
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Elias M, Gani S, Lerner Y, Yamin K, Tor C, Patel A, Matityahu A, Dessau M, Qvit N, Onn I. Developing a peptide to disrupt cohesin head domain interactions. iScience 2023; 26:107498. [PMID: 37664609 PMCID: PMC10470313 DOI: 10.1016/j.isci.2023.107498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 06/16/2023] [Accepted: 07/26/2023] [Indexed: 09/05/2023] Open
Abstract
Cohesin mediates the 3-D structure of chromatin and is involved in maintaining genome stability and function. The cohesin core comprises Smc1 and Smc3, elongated-shaped proteins that dimerize through globular domains at their edges, called head and hinge. ATP binding to the Smc heads induces their dimerization and the formation of two active sites, while ATP hydrolysis results in head disengagement. This ATPase cycle is essential for driving cohesin activity. We report on the development of the first cohesin-inhibiting peptide (CIP). The CIP binds Smc3 in vitro and inhibits the ATPase activity of the holocomplex. Treating yeast cells with the CIP prevents cohesin's tethering activity and, interestingly, leads to the accumulation of cohesin on chromatin. CIP3 also affects cohesin activity in human cells. Altogether, we demonstrate the power of peptides to inhibit cohesin in cells and discuss the potential application of CIPs as a therapeutic approach.
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Affiliation(s)
- Maria Elias
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Samar Gani
- Protein-Protein Interactions Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Yana Lerner
- Protein-Protein Interactions Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Katreen Yamin
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Chen Tor
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Adarsh Patel
- The Lab for Structural Biology of Infectious Diseases, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Avi Matityahu
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Moshe Dessau
- The Lab for Structural Biology of Infectious Diseases, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Nir Qvit
- Protein-Protein Interactions Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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5
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Mfarej MG, Hyland CA, Sanchez AC, Falk MM, Iovine MK, Skibbens RV. Cohesin: an emerging master regulator at the heart of cardiac development. Mol Biol Cell 2023; 34:rs2. [PMID: 36947206 PMCID: PMC10162415 DOI: 10.1091/mbc.e22-12-0557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
Cohesins are ATPase complexes that play central roles in cellular processes such as chromosome division, DNA repair, and gene expression. Cohesinopathies arise from mutations in cohesin proteins or cohesin complex regulators and encompass a family of related developmental disorders that present with a range of severe birth defects, affect many different physiological systems, and often lead to embryonic fatality. Treatments for cohesinopathies are limited, in large part due to the lack of understanding of cohesin biology. Thus, characterizing the signaling networks that lie upstream and downstream of cohesin-dependent pathways remains clinically relevant. Here, we highlight alterations in cohesins and cohesin regulators that result in cohesinopathies, with a focus on cardiac defects. In addition, we suggest a novel and more unifying view regarding the mechanisms through which cohesinopathy-based heart defects may arise.
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Affiliation(s)
- Michael G. Mfarej
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Caitlin A. Hyland
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Annie C. Sanchez
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Matthias M. Falk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - M. Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
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6
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Porter H, Li Y, Neguembor MV, Beltran M, Varsally W, Martin L, Cornejo MT, Pezić D, Bhamra A, Surinova S, Jenner RG, Cosma MP, Hadjur S. Cohesin-independent STAG proteins interact with RNA and R-loops and promote complex loading. eLife 2023; 12:e79386. [PMID: 37010886 PMCID: PMC10238091 DOI: 10.7554/elife.79386] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 04/02/2023] [Indexed: 04/04/2023] Open
Abstract
Most studies of cohesin function consider the Stromalin Antigen (STAG/SA) proteins as core complex members given their ubiquitous interaction with the cohesin ring. Here, we provide functional data to support the notion that the SA subunit is not a mere passenger in this structure, but instead plays a key role in the localization of cohesin to diverse biological processes and promotes loading of the complex at these sites. We show that in cells acutely depleted for RAD21, SA proteins remain bound to chromatin, cluster in 3D and interact with CTCF, as well as with a wide range of RNA binding proteins involved in multiple RNA processing mechanisms. Accordingly, SA proteins interact with RNA, and R-loops, even in the absence of cohesin. Our results place SA1 on chromatin upstream of the cohesin ring and reveal a role for SA1 in cohesin loading which is independent of NIPBL, the canonical cohesin loader. We propose that SA1 takes advantage of structural R-loop platforms to link cohesin loading and chromatin structure with diverse functions. Since SA proteins are pan-cancer targets, and R-loops play an increasingly prevalent role in cancer biology, our results have important implications for the mechanistic understanding of SA proteins in cancer and disease.
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Affiliation(s)
- Hayley Porter
- Research Department of Cancer Biology, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Yang Li
- Research Department of Cancer Biology, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Manuel Beltran
- Regulatory Genomics Group, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Wazeer Varsally
- Research Department of Cancer Biology, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Laura Martin
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Manuel Tavares Cornejo
- Regulatory Genomics Group, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Dubravka Pezić
- Research Department of Cancer Biology, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Amandeep Bhamra
- Proteomics Research Translational Technology Platform, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Silvia Surinova
- Proteomics Research Translational Technology Platform, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Richard G Jenner
- Regulatory Genomics Group, Cancer Institute, University College LondonLondonUnited Kingdom
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
- Institució Catalana de Recerca i Estudis Avançats (ICREA)BarcelonaSpain
| | - Suzana Hadjur
- Research Department of Cancer Biology, Cancer Institute, University College LondonLondonUnited Kingdom
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7
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Shin H, Kim Y. Regulation of loop extrusion on the interphase genome. Crit Rev Biochem Mol Biol 2023; 58:1-18. [PMID: 36921088 DOI: 10.1080/10409238.2023.2182273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
In the human cell nucleus, dynamically organized chromatin is the substrate for gene regulation, DNA replication, and repair. A central mechanism of DNA loop formation is an ATPase motor cohesin-mediated loop extrusion. The cohesin complexes load and unload onto the chromosome under the control of other regulators that physically interact and affect motor activity. Regulation of the dynamic loading cycle of cohesin influences not only the chromatin structure but also genome-associated human disorders and aging. This review focuses on the recently spotlighted genome organizing factors and the mechanism by which their dynamic interactions shape the genome architecture in interphase.
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Affiliation(s)
- Hyogyung Shin
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Yoori Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea.,New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
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8
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Fenech EJ, Cohen N, Kupervaser M, Gazi Z, Schuldiner M. A toolbox for systematic discovery of stable and transient protein interactors in baker's yeast. Mol Syst Biol 2023; 19:e11084. [PMID: 36651308 PMCID: PMC9912024 DOI: 10.15252/msb.202211084] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 01/19/2023] Open
Abstract
Identification of both stable and transient interactions is essential for understanding protein function and regulation. While assessing stable interactions is more straightforward, capturing transient ones is challenging. In recent years, sophisticated tools have emerged to improve transient interactor discovery, with many harnessing the power of evolved biotin ligases for proximity labelling. However, biotinylation-based methods have lagged behind in the model eukaryote, Saccharomyces cerevisiae, possibly due to the presence of several abundant, endogenously biotinylated proteins. In this study, we optimised robust biotin-ligation methodologies in yeast and increased their sensitivity by creating a bespoke technique for downregulating endogenous biotinylation, which we term ABOLISH (Auxin-induced BiOtin LIgase diminiSHing). We used the endoplasmic reticulum insertase complex (EMC) to demonstrate our approaches and uncover new substrates. To make these tools available for systematic probing of both stable and transient interactions, we generated five full-genome collections of strains in which every yeast protein is tagged with each of the tested biotinylation machineries, some on the background of the ABOLISH system. This comprehensive toolkit enables functional interactomics of the entire yeast proteome.
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Affiliation(s)
- Emma J Fenech
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Nir Cohen
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Meital Kupervaser
- The de Botton Protein Profiling Institute of the Nancy and Stephen Grand Israel National Centre for Personalized MedicineWeizmann Institute of ScienceRehovotIsrael
| | - Zohar Gazi
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Maya Schuldiner
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
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9
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Choudhary K, Kupiec M. The cohesin complex of yeasts: sister chromatid cohesion and beyond. FEMS Microbiol Rev 2023; 47:6825453. [PMID: 36370456 DOI: 10.1093/femsre/fuac045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Each time a cell divides, it needs to duplicate the genome and then separate the two copies. In eukaryotes, which usually have more than one linear chromosome, this entails tethering the two newly replicated DNA molecules, a phenomenon known as sister chromatid cohesion (SCC). Cohesion ensures proper chromosome segregation to separate poles during mitosis. SCC is achieved by the presence of the cohesin complex. Besides its canonical function, cohesin is essential for chromosome organization and DNA damage repair. Surprisingly, yeast cohesin is loaded in G1 before DNA replication starts but only acquires its binding activity during DNA replication. Work in microorganisms, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe has greatly contributed to the understanding of cohesin composition and functions. In the last few years, much progress has been made in elucidating the role of cohesin in chromosome organization and compaction. Here, we discuss the different functions of cohesin to ensure faithful chromosome segregation and genome stability during the mitotic cell division in yeast. We describe what is known about its composition and how DNA replication is coupled with SCC establishment. We also discuss current models for the role of cohesin in chromatin loop extrusion and delineate unanswered questions about the activity of this important, conserved complex.
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Affiliation(s)
- Karan Choudhary
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
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10
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Fold-change of chromatin condensation in yeast is a conserved property. Sci Rep 2022; 12:17393. [PMID: 36253460 PMCID: PMC9576780 DOI: 10.1038/s41598-022-22340-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/13/2022] [Indexed: 01/10/2023] Open
Abstract
During mitosis, chromatin is condensed and organized into mitotic chromosomes. Condensation is critical for genome stability and dynamics, yet the degree of condensation is significantly different between multicellular and single-cell eukaryotes. What is less clear is whether there is a minimum degree of chromosome condensation in unicellular eukaryotes. Here, we exploited two-photon microscopy to analyze chromatin condensation in live and fixed cells, enabling studies of some organisms that are not readily amenable to genetic modification. This includes the yeasts Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis, and Candida albicans, as well as a protist Trypanosoma brucei. We found that mitotic chromosomes in this range of species are condensed about 1.5-fold relative to interphase chromatin. In addition, we used two-photon microscopy to reveal that chromatin reorganization in interphase human hepatoma cells infected by the hepatitis C virus is decondensed compared to uninfected cells, which correlates with the previously reported viral-induced changes in chromatin dynamics. This work demonstrates the power of two-photon microscopy to analyze chromatin in a broad range of cell types and conditions, including non-model single-cell eukaryotes. We suggest that similar condensation levels are an evolutionarily conserved property in unicellular eukaryotes and important for proper chromosome segregation. Furthermore, this provides new insights into the process of chromatin condensation during mitosis in unicellular organisms as well as the response of human cells to viral infection.
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11
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A walk through the SMC cycle: From catching DNAs to shaping the genome. Mol Cell 2022; 82:1616-1630. [PMID: 35477004 DOI: 10.1016/j.molcel.2022.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 02/02/2022] [Accepted: 04/04/2022] [Indexed: 12/16/2022]
Abstract
SMC protein complexes are molecular machines that provide structure to chromosomes. These complexes bridge DNA elements and by doing so build DNA loops in cis and hold together the sister chromatids in trans. We discuss how drastic conformational changes allow SMC complexes to build such intricate DNA structures. The tight regulation of these complexes controls fundamental chromosomal processes such as transcription, recombination, repair, and mitosis.
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12
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Bohutínská M, Handrick V, Yant L, Schmickl R, Kolář F, Bomblies K, Paajanen P. De Novo Mutation and Rapid Protein (Co-)evolution during Meiotic Adaptation in Arabidopsis arenosa. Mol Biol Evol 2021; 38:1980-1994. [PMID: 33502506 PMCID: PMC8097281 DOI: 10.1093/molbev/msab001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A sudden shift in environment or cellular context necessitates rapid adaptation. A dramatic example is genome duplication, which leads to polyploidy. In such situations, the waiting time for new mutations might be prohibitive; theoretical and empirical studies suggest that rapid adaptation will largely rely on standing variation already present in source populations. Here, we investigate the evolution of meiosis proteins in Arabidopsis arenosa, some of which were previously implicated in adaptation to polyploidy, and in a diploid, habitat. A striking and unexplained feature of prior results was the large number of amino acid changes in multiple interacting proteins, especially in the relatively young tetraploid. Here, we investigate whether selection on meiosis genes is found in other lineages, how the polyploid may have accumulated so many differences, and whether derived variants were selected from standing variation. We use a range-wide sample of 145 resequenced genomes of diploid and tetraploid A. arenosa, with new genome assemblies. We confirmed signals of positive selection in the polyploid and diploid lineages they were previously reported in and find additional meiosis genes with evidence of selection. We show that the polyploid lineage stands out both qualitatively and quantitatively. Compared with diploids, meiosis proteins in the polyploid have more amino acid changes and a higher proportion affecting more strongly conserved sites. We find evidence that in tetraploids, positive selection may have commonly acted on de novo mutations. Several tests provide hints that coevolution, and in some cases, multinucleotide mutations, might contribute to rapid accumulation of changes in meiotic proteins.
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Affiliation(s)
- Magdalena Bohutínská
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic
| | - Vinzenz Handrick
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Levi Yant
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Roswitha Schmickl
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Botany of the Czech Academy of Sciences, Průhonice, Czech Republic.,Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Kirsten Bomblies
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom.,Plant Evolutionary Genetics, Department of Biology, Institute of Molecular Plant Biology, ETH Zürich, Zurich, Switzerland
| | - Pirita Paajanen
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
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13
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Pathania A, Liu W, Matityahu A, Irudayaraj J, Onn I. Chromosome loading of cohesin depends on conserved residues in Scc3. Curr Genet 2021; 67:447-459. [PMID: 33404730 DOI: 10.1007/s00294-020-01150-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 12/12/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
Cohesin is essential for sister chromatid cohesion, which ensures equal segregation of the chromatids to daughter cells. However, the molecular mechanism by which cohesin mediates this function is elusive. Scc3, one of the four core subunits of cohesin, is vital to cohesin activity. However, the mechanism by which Scc3 contributes to the activity and identity of its functional domains is not fully understood. Here, we describe an in-frame five-amino acid insertion mutation after glutamic acid 704 (scc3-E704ins) in yeast Scc3, located in the middle of the second armadillo repeat. Mutated cohesin-scc3-E704ins complexes are unable to establish cohesion. Detailed molecular and genetic analyses revealed that the mutated cohesin has reduced affinity to the Scc2 loader. This inhibits its enrichment at centromeres and chromosomal arms. Mutant complexes show a slow diffusion rate in live cells suggesting that they induce a major conformational change in the complex. The analysis of systematic mutations in the insertion region of Scc3 revealed two conserved aspartic acid residues that are essential for the activity. The study offers a better understanding of the contribution of Scc3 to cohesin activity and the mechanism by which cohesin tethers the sister chromatids during the cell cycle.
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Affiliation(s)
- Anjali Pathania
- The Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold St, P.O. Box 1589, 1311502, Safed, Israel
| | - Wenjie Liu
- Micro and Nanotechnology Laboratory, Department of Bioengineering, Beckman Institute, Carl Woese Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carle Foundation Hospital, Mills Breast Cancer Institute, Urbana, IL, USA
| | - Avi Matityahu
- The Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold St, P.O. Box 1589, 1311502, Safed, Israel
| | - Joseph Irudayaraj
- Micro and Nanotechnology Laboratory, Department of Bioengineering, Beckman Institute, Carl Woese Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carle Foundation Hospital, Mills Breast Cancer Institute, Urbana, IL, USA
| | - Itay Onn
- The Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold St, P.O. Box 1589, 1311502, Safed, Israel.
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14
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Zuilkoski CM, Skibbens RV. PCNA promotes context-specific sister chromatid cohesion establishment separate from that of chromatin condensation. Cell Cycle 2020; 19:2436-2450. [PMID: 32926661 PMCID: PMC7553509 DOI: 10.1080/15384101.2020.1804221] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/08/2020] [Accepted: 07/24/2020] [Indexed: 10/23/2022] Open
Abstract
Cellular genomes undergo various structural changes that include cis tethering (the tethering together of two loci within a single DNA molecule), which promotes chromosome condensation and transcriptional activation, and trans tethering (the tethering together of two DNA molecules), which promotes sister chromatid cohesion and DNA repair. The protein complex termed cohesin promotes both cis and trans forms of DNA tethering, but the extent to which these cohesin functions occur in temporally or spatially defined contexts remains largely unknown. Prior studies indicate that DNA polymerase sliding clamp PCNA recruits cohesin acetyltransferase Eco1, suggesting that sister chromatid cohesion is established in the context of the DNA replication fork. In support of this model, elevated levels of PCNA rescue the temperature growth and cohesion defects exhibited by eco1 mutant cells. Here, we test whether Eco1-dependent chromatin condensation is also promoted in the context of this DNA replication fork component. Our results reveal that overexpressed PCNA does not promote DNA condensation in eco1 mutant cells, even though Smc3 acetylation levels are increased. We further provide evidence that replication fork-associated E3 ligase impacts on Eco1 are more complex that previously described. In combination, the data suggests that Eco1 acetylates Smc3 and thus promotes sister chromatid cohesion in context of the DNA replication fork, whereas a distinct cohesin population participates in chromatin condensation outside the context of the DNA replication fork.
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Affiliation(s)
- Caitlin M. Zuilkoski
- Department of Biological Sciences, Lehigh University, 18015, Bethlehem, Pennsylvania, USA
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, 18015, Bethlehem, Pennsylvania, USA
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15
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Shen D, Skibbens RV. Promotion of Hyperthermic-Induced rDNA Hypercondensation in Saccharomyces cerevisiae. Genetics 2020; 214:589-604. [PMID: 31980450 PMCID: PMC7054013 DOI: 10.1534/genetics.119.302994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/29/2019] [Indexed: 12/11/2022] Open
Abstract
Ribosome biogenesis is tightly regulated through stress-sensing pathways that impact genome stability, aging and senescence. In Saccharomyces cerevisiae, ribosomal RNAs are transcribed from rDNA located on the right arm of chromosome XII. Numerous studies reveal that rDNA decondenses into a puff-like structure during interphase, and condenses into a tight loop-like structure during mitosis. Intriguingly, a novel and additional mechanism of increased mitotic rDNA compaction (termed hypercondensation) was recently discovered that occurs in response to temperature stress (hyperthermic-induced) and is rapidly reversible. Here, we report that neither changes in condensin binding or release of DNA during mitosis, nor mutation of factors that regulate cohesin binding and release, appear to play a critical role in hyperthermic-induced rDNA hypercondensation. A candidate genetic approach revealed that deletion of either HSP82 or HSC82 (Hsp90 encoding heat shock paralogs) result in significantly reduced hyperthermic-induced rDNA hypercondensation. Intriguingly, Hsp inhibitors do not impact rDNA hypercondensation. In combination, these findings suggest that Hsp90 either stabilizes client proteins, which are sensitive to very transient thermic challenges, or directly promotes rDNA hypercondensation during preanaphase. Our findings further reveal that the high mobility group protein Hmo1 is a negative regulator of mitotic rDNA condensation, distinct from its role in promoting premature condensation of rDNA during interphase upon nutrient starvation.
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Affiliation(s)
- Donglai Shen
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015
| | - Robert V Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015
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16
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Hsieh YYP, Makrantoni V, Robertson D, Marston AL, Murray AW. Evolutionary repair: Changes in multiple functional modules allow meiotic cohesin to support mitosis. PLoS Biol 2020; 18:e3000635. [PMID: 32155147 PMCID: PMC7138332 DOI: 10.1371/journal.pbio.3000635] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/07/2020] [Accepted: 02/21/2020] [Indexed: 12/12/2022] Open
Abstract
The role of proteins often changes during evolution, but we do not know how cells adapt when a protein is asked to participate in a different biological function. We forced the budding yeast, Saccharomyces cerevisiae, to use the meiosis-specific kleisin, recombination 8 (Rec8), during the mitotic cell cycle, instead of its paralog, Scc1. This perturbation impairs sister chromosome linkage, advances the timing of genome replication, and reduces reproductive fitness by 45%. We evolved 15 parallel populations for 1,750 generations, substantially increasing their fitness, and analyzed the genotypes and phenotypes of the evolved cells. Only one population contained a mutation in Rec8, but many populations had mutations in the transcriptional mediator complex, cohesin-related genes, and cell cycle regulators that induce S phase. These mutations improve sister chromosome cohesion and delay genome replication in Rec8-expressing cells. We conclude that changes in known and novel partners allow cells to use an existing protein to participate in new biological functions.
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Affiliation(s)
- Yu-Ying Phoebe Hsieh
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Vasso Makrantoni
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel Robertson
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Adèle L. Marston
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew W. Murray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
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17
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Liu W, Biton E, Pathania A, Matityahu A, Irudayaraj J, Onn I. Monomeric cohesin state revealed by live-cell single-molecule spectroscopy. EMBO Rep 2020; 21:e48211. [PMID: 31886609 PMCID: PMC7001500 DOI: 10.15252/embr.201948211] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 11/28/2019] [Accepted: 12/04/2019] [Indexed: 12/17/2022] Open
Abstract
The cohesin complex plays an important role in the maintenance of genome stability. Cohesin is composed of four core subunits and a set of regulatory subunits that interact with the core subunits. Less is known about cohesin dynamics in live cells and on the contribution of individual subunits to the overall complex. Understanding the tethering mechanism of cohesin is still a challenge, especially because the proposed mechanisms are still not conclusive. Models proposed to describe tethering depend on either the monomeric cohesin ring or a cohesin dimer. Here, we investigate the role of cohesin dynamics and stoichiometry in live yeast cells at single-molecule resolution. We explore the effect of regulatory subunit deletion on cohesin mobility and found that depletion of different regulatory subunits has opposing effects. Finally, we show that cohesin exists mostly as a canonical monomer throughout the cell cycle, and its monomeric form is independent of its regulatory factors. Our results demonstrate that single-molecule tools have the potential to provide new insights into the cohesin mechanism of action in live cells.
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Affiliation(s)
- Wenjie Liu
- Department of Bioengineering, Micro and Nanotechnology LaboratoryCancer Center at IllinoisUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
- Mills Breast Cancer InstituteCarle Foundation HospitalUrbanaILUSA
| | - Elisheva Biton
- The Azrieli Faculty of MedicineBar‐Ilan UniversitySafedIsrael
| | - Anjali Pathania
- The Azrieli Faculty of MedicineBar‐Ilan UniversitySafedIsrael
| | - Avi Matityahu
- The Azrieli Faculty of MedicineBar‐Ilan UniversitySafedIsrael
| | - Joseph Irudayaraj
- Department of Bioengineering, Micro and Nanotechnology LaboratoryCancer Center at IllinoisUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
- Mills Breast Cancer InstituteCarle Foundation HospitalUrbanaILUSA
| | - Itay Onn
- The Azrieli Faculty of MedicineBar‐Ilan UniversitySafedIsrael
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18
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Li Y, Haarhuis JHI, Sedeño Cacciatore Á, Oldenkamp R, van Ruiten MS, Willems L, Teunissen H, Muir KW, de Wit E, Rowland BD, Panne D. The structural basis for cohesin-CTCF-anchored loops. Nature 2020; 578:472-476. [PMID: 31905366 PMCID: PMC7035113 DOI: 10.1038/s41586-019-1910-z] [Citation(s) in RCA: 227] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 12/05/2019] [Indexed: 12/11/2022]
Abstract
Cohesin catalyses the folding of the genome into loops that are anchored by CTCF1. The molecular mechanism of how cohesin and CTCF structure the 3D genome has remained unclear. Here we show that a segment within the CTCF N terminus interacts with the SA2-SCC1 subunits of human cohesin. We report a crystal structure of SA2-SCC1 in complex with CTCF at a resolution of 2.7 Å, which reveals the molecular basis of the interaction. We demonstrate that this interaction is specifically required for CTCF-anchored loops and contributes to the positioning of cohesin at CTCF binding sites. A similar motif is present in a number of established and newly identified cohesin ligands, including the cohesin release factor WAPL2,3. Our data suggest that CTCF enables the formation of chromatin loops by protecting cohesin against loop release. These results provide fundamental insights into the molecular mechanism that enables the dynamic regulation of chromatin folding by cohesin and CTCF.
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Affiliation(s)
- Yan Li
- European Molecular Biology Laboratory, Grenoble, France
| | - Judith H I Haarhuis
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - Roel Oldenkamp
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marjon S van Ruiten
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Laureen Willems
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Hans Teunissen
- Division of Gene Regulation, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Kyle W Muir
- European Molecular Biology Laboratory, Grenoble, France.
- MRC Laboratory of Molecular Biology, Cambridge, UK.
| | - Elzo de Wit
- Division of Gene Regulation, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| | - Benjamin D Rowland
- Division of Gene Regulation, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| | - Daniel Panne
- European Molecular Biology Laboratory, Grenoble, France.
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
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19
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Yamin K, Assa M, Matityahu A, Onn I. Analyzing chromosome condensation in yeast by second-harmonic generation microscopy. Curr Genet 2019; 66:437-443. [PMID: 31535185 DOI: 10.1007/s00294-019-01034-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 08/25/2019] [Accepted: 09/04/2019] [Indexed: 01/02/2023]
Abstract
Condensation is a fundamental property of mitotic chromosomes in eukaryotic cells. However, analyzing chromosome condensation in yeast is a challenging task while existing methods have notable weaknesses. Second-harmonic generation (SHG) microscopy is a label-free, advanced imaging technique for measuring the surface curve of isotropic molecules such as chromatin in live cells. We applied this method to detect changes in chromatin organization throughout the cell cycle in live yeast cells. We showed that SHG microscopy can be used to identify changes in chromatin organization throughout the cell cycle and in response to inactivation of the SMC complexes, cohesin and condensin. Implementation of this method will improve our ability to analyze chromatin structure in protozoa and will enhance our understanding of chromatin organization in eukaryotic cells.
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Affiliation(s)
- Katreena Yamin
- Chromosome Instability and Dynamics Laboratory, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michael Assa
- Imaging Unit, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Avi Matityahu
- Chromosome Instability and Dynamics Laboratory, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Laboratory, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
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20
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Boginya A, Detroja R, Matityahu A, Frenkel-Morgenstern M, Onn I. The chromatin remodeler Chd1 regulates cohesin in budding yeast and humans. Sci Rep 2019; 9:8929. [PMID: 31222142 PMCID: PMC6586844 DOI: 10.1038/s41598-019-45263-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 06/04/2019] [Indexed: 12/24/2022] Open
Abstract
Chd1 is a chromatin remodeler that is involved in nucleosome positioning and transcription. Deletion of CHD1 is a frequent event in prostate cancer. The Structural Maintenance of Chromosome (SMC) complex cohesin mediates long-range chromatin interactions and is involved in maintaining genome stability. We provide new evidence that Chd1 is a regulator of cohesin. In the yeast S. cerevisiae, Chd1 is not essential for viability. We show that deletion of the gene leads to a defect in sister chromatid cohesion and in chromosome morphology. Chl1 is a non-essential DNA helicase that has been shown to regulate cohesin loading. Surprisingly, co-deletion of CHD1 and CHL1 results in an additive cohesion defect but partial suppression of the chromosome structure phenotype. We found that the cohesin regulator Pds5 is overexpressed when Chd1 and Chl1 are deleted. However, Pds5 expression is reduced to wild type levels when both genes are deleted. Finally, we show a correlation in the expression of CHD1 and cohesin genes in prostate cancer patients. Furthermore, we show that overexpression of cohesin subunits is correlated with the aggressiveness of the tumor. The biological roles of the interplay between Chd1, Chl1 and SMCs are discussed.
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Affiliation(s)
- Alexandra Boginya
- Chromosome Instability and Dynamics Lab. The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Rajesh Detroja
- Cancer Genomics and Biocomputing of Complex Diseases Lab. The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Avi Matityahu
- Chromosome Instability and Dynamics Lab. The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Milana Frenkel-Morgenstern
- Cancer Genomics and Biocomputing of Complex Diseases Lab. The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Lab. The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
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21
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Guacci V, Chatterjee F, Robison B, Koshland DE. Communication between distinct subunit interfaces of the cohesin complex promotes its topological entrapment of DNA. eLife 2019; 8:e46347. [PMID: 31162048 PMCID: PMC6579514 DOI: 10.7554/elife.46347] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/04/2019] [Indexed: 12/21/2022] Open
Abstract
Cohesin mediates higher order chromosome structure. Its biological activities require topological entrapment of DNA within a lumen(s) formed by cohesin subunits. The reversible dissociation of cohesin's Smc3p and Mcd1p subunits is postulated to form a regulated gate that allows DNA entry and exit into the lumen. We assessed gate-independent functions of this interface in yeast using a fusion protein that joins Smc3p to Mcd1p. We show that in vivo all the regulators of cohesin promote DNA binding of cohesin by mechanisms independent of opening this gate. Furthermore, we show that this interface has a gate-independent activity essential for cohesin to bind chromosomes. We propose that this interface regulates DNA entrapment by controlling the opening and closing of one or more distal interfaces formed by cohesin subunits, likely by inducing a conformation change in cohesin. Furthermore, cohesin regulators modulate the interface to control both DNA entrapment and cohesin functions after DNA binding.
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Affiliation(s)
- Vincent Guacci
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Fiona Chatterjee
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Brett Robison
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Douglas E Koshland
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
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22
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Perez S, Gevor M, Davidovich A, Kaspi A, Yamin K, Domovich T, Meirson T, Matityahu A, Brody Y, Stemmer SM, El-Osta A, Haviv I, Onn I, Gal-Tanamy M. Dysregulation of the cohesin subunit RAD21 by Hepatitis C virus mediates host-virus interactions. Nucleic Acids Res 2019; 47:2455-2471. [PMID: 30698808 PMCID: PMC6412124 DOI: 10.1093/nar/gkz052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/30/2018] [Accepted: 01/24/2019] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) infection is the leading cause of chronic hepatitis, which often results in liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). HCV possesses an RNA genome and its replication is confined to the cytoplasm. Yet, infection with HCV leads to global changes in gene expression, and chromosomal instability (CIN) in the host cell. The mechanisms by which the cytoplasmic virus affects these nuclear processes are elusive. Here, we show that HCV modulates the function of the Structural Maintenance of Chromosome (SMC) protein complex, cohesin, which tethers remote regions of chromatin. We demonstrate that infection of hepatoma cells with HCV leads to up regulation of the expression of the RAD21 cohesin subunit and changes cohesin residency on the chromatin. These changes regulate the expression of genes associated with virus-induced pathways. Furthermore, siRNA downregulation of viral-induced RAD21 reduces HCV infection. During mitosis, HCV infection induces hypercondensation of chromosomes and the appearance of multi-centrosomes. We provide evidence that the underlying mechanism involves the viral NS3/4 protease and the cohesin regulator, WAPL. Altogether, our results provide the first evidence that HCV induces changes in gene expression and chromosome structure of infected cells by modulating cohesin.
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Affiliation(s)
- Shira Perez
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
- Cancer Personalized Medicine and Diagnostic Genomics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michael Gevor
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ateret Davidovich
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Antony Kaspi
- Epigenetics in Human Health and Disease Laboratory, Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
| | - Katreena Yamin
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Tom Domovich
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Tomer Meirson
- Cell Migration and Invasion Laboratory, Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel
| | - Avi Matityahu
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Yehuda Brody
- The Broad institute of Harvard and MIT, Cambridge, MA, USA
| | - Salomon M Stemmer
- Davidoff Center, Rabin Medical Center, Beilinson Campus, Petach Tikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Assam El-Osta
- Epigenetics in Human Health and Disease Laboratory, Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
- Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR
| | - Izhak Haviv
- Cancer Personalized Medicine and Diagnostic Genomics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meital Gal-Tanamy
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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23
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Hong S, Joo JH, Yun H, Kim K. The nature of meiotic chromosome dynamics and recombination in budding yeast. J Microbiol 2019; 57:221-231. [PMID: 30671743 DOI: 10.1007/s12275-019-8541-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 12/28/2022]
Abstract
During meiosis, crossing over allows for the exchange of genes between homologous chromosomes, enabling their segregation and leading to genetic variation in the resulting gametes. Spo11, a topoisomerase-like protein expressed in eukaryotes, and diverse accessory factors induce programmed double-strand breaks (DSBs) to initiate meiotic recombination during the early phase of meiosis after DNA replication. DSBs are further repaired via meiosis-specific homologous recombination. Studies on budding yeast have provided insights into meiosis and genetic recombination and have improved our understanding of higher eukaryotic systems. Cohesin, a chromosome-associated multiprotein complex, mediates sister chromatid cohesion (SCC), and is conserved from yeast to humans. Diverse cohesin subunits in budding yeast have been identified in DNA metabolic pathways, such as DNA replication, chromosome segregation, recombination, DNA repair, and gene regulation. During cell cycle, SCC is established by multiple cohesin subunits, which physically bind sister chromatids together and modulate proteins that involve in the capturing and separation of sister chromatids. Cohesin components include at least four core subunits that establish and maintain SCC: two structural maintenance chromosome subunits (Smc1 and Smc3), an α-kleisin subunit (Mcd1/Scc1 during mitosis and Rec8 during meiosis), and Scc3/Irr1 (SA1 and SA2). In addition, the cohesin-associated factors Pds5 and Rad61 regulate structural modifications and cell cyclespecific dynamics of chromatin to ensure accurate chromosome segregation. In this review, we discuss SCC and the recombination pathway, as well as the relationship between the two processes in budding yeast, and we suggest a possible conserved mechanism for meiotic chromosome dynamics from yeast to humans.
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Affiliation(s)
- Soogil Hong
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Jeong Hwan Joo
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyeseon Yun
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Keunpil Kim
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea.
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24
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Matityahu A, Shwartz M, Onn I. Identifying Functional Domains in Subunits of Structural Maintenance of Chromosomes (SMC) Complexes by Transposon Mutagenesis Screen in Yeast. Methods Mol Biol 2019; 2004:63-78. [PMID: 31147910 DOI: 10.1007/978-1-4939-9520-2_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Structural maintenance of chromosomes (SMC) complexes mediate higher order chromosome structures. Eukaryotic cells contain three distinct SMC complexes called cohesin, condensin, and SMC5/6, which share the same basic architecture. The core of SMC complexes contains a heterodimer of SMC proteins, a kleisin subunit, and a set of regulatory proteins that contain HEAT and Armadillo (ARM) repeat protein-protein interaction motifs. A major challenge in studying SMC proteins and their auxiliary factors is identifying their functional domains. Bioinformatics is not an efficient way to achieve this goal because of the absence of defined sequence and structural motifs. Functional domains can be identified experimentally by performing a genetic screen and isolating functional mutants. While there are several strategies to conduct a screen, the quaternary structure of SMCs makes them excellent candidates to transposon-based random insertion mutagenesis, followed by selection of dominant negative mutants. In this chapter we list the advantages of this approach in the context of SMC complexes. We provide a detailed protocol for performing the screen in S. cerevisiae and use data from our recently reported screen on the ARM repeat protein, Scc4, to demonstrate the key steps in the protocol.
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Affiliation(s)
- Avi Matityahu
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michal Shwartz
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
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25
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Ali EI, Loidl J, Howard-Till RA. A streamlined cohesin apparatus is sufficient for mitosis and meiosis in the protist Tetrahymena. Chromosoma 2018; 127:421-435. [PMID: 29948142 PMCID: PMC6208729 DOI: 10.1007/s00412-018-0673-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/18/2018] [Accepted: 05/28/2018] [Indexed: 02/03/2023]
Abstract
In order to understand its diverse functions, we have studied cohesin in the evolutionarily distant ciliate model organism Tetrahymena thermophila. In this binucleate cell, the heritable germline genome is maintained separately from the transcriptionally active somatic genome. In a previous study, we showed that a minimal cohesin complex in Tetrahymena consisted of homologs of Smc1, Smc3, and Rec8, which are present only in the germline nucleus, where they are needed for normal chromosome segregation as well as meiotic DNA repair. In this study, we confirm that a putative homolog of Scc3 is a member of this complex. In the absence of Scc3, Smc1 and Rec8 fail to localize to germline nuclei, Rec8 is hypo-phosphorylated, and cells show phenotypes similar to depletion of Smc1 and Rec8. We also identify a homolog of Scc2, which in other organisms is part of a heterodimeric complex (Scc2/Scc4) that helps load cohesin onto chromatin. In Tetrahymena, Scc2 interacts with Rec8 and Scc3, and its absence causes defects in mitotic and meiotic divisions. Scc2 is not required for chromosomal association of cohesin, but Rec8 is hypo-phosphorylated in its absence. Moreover, we did not identify a homolog of the cohesin loader Scc4, and no evidence was found of auxiliary factors, such as Eco1, Pds5, or WAPL. We propose that in Tetrahymena, a single, minimal cohesin complex performs all necessary functions for germline mitosis and meiosis, but is dispensable for transcription regulation and chromatin organization of the somatic genome.
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Affiliation(s)
- Emine I Ali
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Rachel A Howard-Till
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria.
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26
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Villa-Hernández S, Bermejo R. Replisome-Cohesin Interfacing: A Molecular Perspective. Bioessays 2018; 40:e1800109. [PMID: 30106480 DOI: 10.1002/bies.201800109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/23/2018] [Indexed: 12/27/2022]
Abstract
Cohesion is established in S-phase through the action of key replisome factors as replication forks engage cohesin molecules. By holding sister chromatids together, cohesion critically assists both an equal segregation of the duplicated genetic material and an efficient repair of DNA breaks. Nonetheless, the molecular events leading the entrapment of nascent chromatids by cohesin during replication are only beginning to be understood. The authors describe here the essential structural features of the cohesin complex in connection to its ability to associate DNA molecules and review the current knowledge on the architectural-functional organization of the eukaryotic replisome, significantly advanced by recent biochemical and structural studies. In light of this novel insight, the authors discuss the mechanisms proposed to assist interfacing of replisomes with chromatin-bound cohesin complexes and elaborate on models for nascent chromatids entrapment by cohesin in the environment of the replication fork.
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Affiliation(s)
- Sara Villa-Hernández
- Centro de Investigaciones Biológicas (CIB-CSIC), Calle Ramiro de Maeztu 928040 Madrid, Spain
| | - Rodrigo Bermejo
- Centro de Investigaciones Biológicas (CIB-CSIC), Calle Ramiro de Maeztu 928040 Madrid, Spain
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27
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Li Y, Muir KW, Bowler MW, Metz J, Haering CH, Panne D. Structural basis for Scc3-dependent cohesin recruitment to chromatin. eLife 2018; 7:e38356. [PMID: 30109982 PMCID: PMC6120753 DOI: 10.7554/elife.38356] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
The cohesin ring complex is required for numerous chromosomal transactions including sister chromatid cohesion, DNA damage repair and transcriptional regulation. How cohesin engages its chromatin substrate has remained an unresolved question. We show here, by determining a crystal structure of the budding yeast cohesin HEAT-repeat subunit Scc3 bound to a fragment of the Scc1 kleisin subunit and DNA, that Scc3 and Scc1 form a composite DNA interaction module. The Scc3-Scc1 subcomplex engages double-stranded DNA through a conserved, positively charged surface. We demonstrate that this conserved domain is required for DNA binding by Scc3-Scc1 in vitro, as well as for the enrichment of cohesin on chromosomes and for cell viability. These findings suggest that the Scc3-Scc1 DNA-binding interface plays a central role in the recruitment of cohesin complexes to chromosomes and therefore for cohesin to faithfully execute its functions during cell division.
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Affiliation(s)
- Yan Li
- European Molecular Biology LaboratoryGrenobleFrance
| | - Kyle W Muir
- European Molecular Biology LaboratoryGrenobleFrance
| | | | - Jutta Metz
- Cell Biology and Biophysics UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
- Structural and Computational Biology UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
| | - Christian H Haering
- Cell Biology and Biophysics UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
- Structural and Computational Biology UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
| | - Daniel Panne
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell BiologyUniversity of LeicesterLeicesterUnited Kingdom
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28
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Robison B, Guacci V, Koshland D. A role for the Smc3 hinge domain in the maintenance of sister chromatid cohesion. Mol Biol Cell 2018; 29:339-355. [PMID: 29187575 PMCID: PMC5996953 DOI: 10.1091/mbc.e17-08-0511] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/15/2017] [Accepted: 11/20/2017] [Indexed: 11/11/2022] Open
Abstract
Cohesin is a conserved protein complex required for sister chromatid cohesion, chromosome condensation, DNA damage repair, and regulation of transcription. Although cohesin functions to tether DNA duplexes, the contribution of its individual domains to this activity remains poorly understood. We interrogated the Smc3p subunit of cohesin by random insertion mutagenesis. Analysis of a mutant in the Smc3p hinge revealed an unexpected role for this domain in cohesion maintenance and condensation. Further investigation revealed that the Smc3p hinge functions at a step following cohesin's stable binding to chromosomes and independently of Smc3p's regulation by the Eco1p acetyltransferase. Hinge mutant phenotypes resemble loss of Pds5p, which binds opposite the hinge near Smc3p's head domain. We propose that a specific conformation of the Smc3p hinge and Pds5p cooperate to promote cohesion maintenance and condensation.
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Affiliation(s)
- Brett Robison
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Vincent Guacci
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Douglas Koshland
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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29
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Schalbetter SA, Goloborodko A, Fudenberg G, Belton JM, Miles C, Yu M, Dekker J, Mirny L, Baxter J. SMC complexes differentially compact mitotic chromosomes according to genomic context. Nat Cell Biol 2017; 19:1071-1080. [PMID: 28825700 PMCID: PMC5640152 DOI: 10.1038/ncb3594] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/19/2017] [Indexed: 12/26/2022]
Abstract
Structural maintenance of chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modelling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids, while condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate that this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead, it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes.
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MESH Headings
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphatases/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Chromatin/chemistry
- Chromatin/genetics
- Chromatin/metabolism
- Chromatin Assembly and Disassembly
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosome Structures
- Chromosomes, Fungal/chemistry
- Chromosomes, Fungal/genetics
- Chromosomes, Fungal/metabolism
- Computer Simulation
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- DNA, Fungal/metabolism
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- DNA, Ribosomal/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Mitosis
- Models, Genetic
- Models, Molecular
- Multiprotein Complexes/genetics
- Multiprotein Complexes/metabolism
- Nucleic Acid Conformation
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/growth & development
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Structure-Activity Relationship
- Cohesins
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Affiliation(s)
| | - Anton Goloborodko
- Institute for Medical Engineering and Sciences, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Geoffrey Fudenberg
- Institute for Medical Engineering and Sciences, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jon-Matthew Belton
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Catrina Miles
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Miao Yu
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Job Dekker
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Leonid Mirny
- Institute for Medical Engineering and Sciences, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Jonathan Baxter
- Genome Damage and Stability Centre, Science Park Road, University of Sussex, Falmer, Brighton BN1 9RQ, UK
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30
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Matityahu A, Onn I. A new twist in the coil: functions of the coiled-coil domain of structural maintenance of chromosome (SMC) proteins. Curr Genet 2017; 64:109-116. [PMID: 28835994 DOI: 10.1007/s00294-017-0735-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 08/15/2017] [Accepted: 08/17/2017] [Indexed: 02/07/2023]
Abstract
The higher-order organization of chromosomes ensures their stability and functionality. However, the molecular mechanism by which higher order structure is established is poorly understood. Dissecting the activity of the relevant proteins provides information essential for achieving a comprehensive understanding of chromosome structure. Proteins of the structural maintenance of chromosome (SMC) family of ATPases are the core of evolutionary conserved complexes. SMC complexes are involved in regulating genome dynamics and in maintaining genome stability. The structure of all SMC proteins resembles an elongated rod that contains a central coiled-coil domain, a common protein structural motif in which two α-helices twist together. In recent years, the imperative role of the coiled-coil domain to SMC protein activity and regulation has become evident. Here, we discuss recent advances in the function of the SMC coiled coils. We describe the structure of the coiled-coil domain of SMC proteins, modifications and interactions that are mediated by it. Furthermore, we assess the role of the coiled-coil domain in conformational switches of SMC proteins, and in determining the architecture of the SMC dimer. Finally, we review the interplay between mutations in the coiled-coil domain and human disorders. We suggest that distinctive properties of coiled coils of different SMC proteins contribute to their distinct functions. The discussion clarifies the mechanisms underlying the activity of SMC proteins, and advocates future studies to elucidate the function of the SMC coiled coil domain.
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Affiliation(s)
- Avi Matityahu
- Faculty of Medicine in the Galilee, Bar-Ilan University, 8 Henrietta Szold St., P.O. Box 1589, 1311502, Safed, Israel
| | - Itay Onn
- Faculty of Medicine in the Galilee, Bar-Ilan University, 8 Henrietta Szold St., P.O. Box 1589, 1311502, Safed, Israel.
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31
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Papagiannakis A, de Jonge JJ, Zhang Z, Heinemann M. Quantitative characterization of the auxin-inducible degron: a guide for dynamic protein depletion in single yeast cells. Sci Rep 2017; 7:4704. [PMID: 28680098 PMCID: PMC5498663 DOI: 10.1038/s41598-017-04791-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/22/2017] [Indexed: 11/24/2022] Open
Abstract
Perturbations are essential for the interrogation of biological systems. The auxin-inducible degron harbors great potential for dynamic protein depletion in yeast. Here, we thoroughly and quantitatively characterize the auxin-inducible degron in single yeast cells. We show that an auxin concentration of 0.25 mM is necessary for fast and uniform protein depletion between single cells, and that in mother cells proteins are depleted faster than their daughters. Although, protein recovery starts immediately after removal of auxin, it takes multiple generations before equilibrium is reached between protein synthesis and dilution, which is when the original protein levels are restored. Further, we found that blue light, used for GFP excitation, together with auxin results in growth defects, caused by the photo-destruction of auxin to its toxic derivatives, which can be avoided if indole-free auxin substitutes are used. Our work provides guidelines for the successful combination of microscopy, microfluidics and the auxin-inducible degron, offering the yeast community an unprecedented tool for dynamic perturbations on the single cell level.
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Affiliation(s)
- Alexandros Papagiannakis
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Janeska J de Jonge
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Zheng Zhang
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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32
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Litwin I, Bakowski T, Maciaszczyk-Dziubinska E, Wysocki R. The LSH/HELLS homolog Irc5 contributes to cohesin association with chromatin in yeast. Nucleic Acids Res 2017; 45:6404-6416. [PMID: 28383696 PMCID: PMC5499779 DOI: 10.1093/nar/gkx240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 03/28/2017] [Accepted: 04/03/2017] [Indexed: 11/29/2022] Open
Abstract
Accurate chromosome segregation is essential for every living cell as unequal distribution of chromosomes during cell division may result in genome instability that manifests in carcinogenesis and developmental disorders. Irc5 from Saccharomyces cerevisiae is a member of the conserved Snf2 family of ATP-dependent DNA translocases and its function is poorly understood. Here, we identify Irc5 as a novel interactor of the cohesin complex. Irc5 associates with Scc1 cohesin subunit and contributes to cohesin binding to chromatin. Disruption of IRC5 decreases cohesin levels at centromeres and chromosome arms, causing premature sister chromatid separation. Moreover, reduced cohesin occupancy at the rDNA region in cells lacking IRC5 leads to the loss of rDNA repeats. We also show that the translocase activity of Irc5 is required for its function in cohesion pathway. Finally, we demonstrate that in the absence of Irc5 both the level of chromatin-bound Scc2, a member of cohesin loading complex, and physical interaction between Scc1 and Scc2 are reduced. Our results suggest that Irc5 is an auxiliary factor that is involved in cohesin association with chromatin.
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Affiliation(s)
- Ireneusz Litwin
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Tomasz Bakowski
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland
| | | | - Robert Wysocki
- Institute of Experimental Biology, University of Wroclaw, 50-328 Wroclaw, Poland
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33
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Abstract
Chromatin condensation during mitosis produces detangled and discrete DNA entities required for high fidelity sister chromatid segregation during mitosis and positions DNA away from the cleavage furrow during cytokinesis. Regional condensation during G1 also establishes a nuclear architecture through which gene transcription is regulated but remains plastic so that cells can respond to changes in nutrient levels, temperature and signaling molecules. To date, however, the potential impact of this plasticity on mitotic chromosome condensation remains unknown. Here, we report results obtained from a new condensation assay that wildtype budding yeast cells exhibit dramatic changes in rDNA conformation in response to temperature. rDNA hypercondenses in wildtype cells maintained at 37°C, compared with cells maintained at 23°C. This hypercondensation machinery can be activated during preanaphase but readily inactivated upon exposure to lower temperatures. Extended mitotic arrest at 23°C does not result in hypercondensation, negating a kinetic-based argument in which condensation that typically proceeds slowly is accelerated when cells are placed at 37°C. Neither elevated recombination nor reduced transcription appear to promote this hypercondensation. This heretofore undetected temperature-dependent hypercondensation pathway impacts current views of chromatin structure based on conditional mutant gene analyses and significantly extends our understanding of physiologic changes in chromatin architecture in response to hypothermia.
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Affiliation(s)
- Donglai Shen
- a Department of Biological Sciences , Lehigh University , Bethlehem , PA , USA
| | - Robert V Skibbens
- a Department of Biological Sciences , Lehigh University , Bethlehem , PA , USA
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34
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Minina EA, Reza SH, Gutierrez-Beltran E, Elander PH, Bozhkov PV, Moschou PN. The Arabidopsis homolog of Scc4/MAU2 is essential for embryogenesis. J Cell Sci 2017; 130:1051-1063. [PMID: 28137757 DOI: 10.1242/jcs.196865] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 01/25/2017] [Indexed: 01/25/2023] Open
Abstract
Factors regulating dynamics of chromatin structure have direct impact on expression of genetic information. Cohesin is a multi-subunit protein complex that is crucial for pairing sister chromatids during cell division, DNA repair and regulation of gene transcription and silencing. In non-plant species, cohesin is loaded on chromatin by the Scc2-Scc4 complex (also known as the NIBPL-MAU2 complex). Here, we identify the Arabidopsis homolog of Scc4, which we denote Arabidopsis thaliana (At)SCC4, and show that it forms a functional complex with AtSCC2, the homolog of Scc2. We demonstrate that AtSCC2 and AtSCC4 act in the same pathway, and that both proteins are indispensable for cell fate determination during early stages of embryo development. Mutant embryos lacking either of these proteins develop only up to the globular stage, and show the suspensor overproliferation phenotype preceded by ectopic auxin maxima distribution. We further establish a new assay to reveal the AtSCC4-dependent dynamics of cohesin loading on chromatin in vivo Our findings define the Scc2-Scc4 complex as an evolutionary conserved machinery controlling cohesin loading and chromatin structure maintenance, and provide new insight into the plant-specific role of this complex in controlling cell fate during embryogenesis.
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Affiliation(s)
- Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, Uppsala SE-75007, Sweden
| | - Salim Hossain Reza
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, Uppsala SE-75007, Sweden
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7080, Uppsala SE-75007, Sweden
| | - Emilio Gutierrez-Beltran
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, Uppsala SE-75007, Sweden
| | - Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, Uppsala SE-75007, Sweden
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, Uppsala SE-75007, Sweden
| | - Panagiotis N Moschou
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7080, Uppsala SE-75007, Sweden
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35
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Kowalec P, Fronk J, Kurlandzka A. The Irr1/Scc3 protein implicated in chromosome segregation in Saccharomyces cerevisiae has a dual nuclear-cytoplasmic localization. Cell Div 2017; 12:1. [PMID: 28077952 PMCID: PMC5223379 DOI: 10.1186/s13008-016-0027-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 12/15/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Correct chromosome segregation depends on the sister chromatid cohesion complex. The essential, evolutionarily conserved regulatory protein Irr1/Scc3, is responsible for the complex loading onto DNA and for its removal. We found that, unexpectedly, Irr1 is present not only in the nucleus but also in the cytoplasm. RESULTS We show that Irr1 protein is enriched in the cytoplasm upon arrest of yeast cells in G1 phase following nitrogen starvation, diauxic shift or α-factor action, and also during normal cell cycle. Despite the presence of numerous Crm1-dependent export signals, the cytoplasmic pool of Irr1 is not derived through export from the nucleus but instead is simply retained in the cytoplasm. Cytoplasmic Irr1 interacts with the Imi1 protein implicated in glutathione homeostasis and mitochondrial integrity. CONCLUSIONS Besides regulation of the sister chromatid cohesion complex in the nucleus Irr1 appears to have an additional role in the cytoplasm, possibly through interaction with the cytoplasmic protein Imi1.
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Affiliation(s)
- Piotr Kowalec
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Jan Fronk
- Department of Molecular Biology, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Kurlandzka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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36
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Abstract
Cohesin is a large ring-shaped protein complex, conserved from yeast to human, which participates in most DNA transactions that take place in the nucleus. It mediates sister chromatid cohesion, which is essential for chromosome segregation and homologous recombination (HR)-mediated DNA repair. Together with architectural proteins and transcriptional regulators, such as CTCF and Mediator, respectively, it contributes to genome organization at different scales and thereby affects transcription, DNA replication, and locus rearrangement. Although cohesin is essential for cell viability, partial loss of function can affect these processes differently in distinct cell types. Mutations in genes encoding cohesin subunits and regulators of the complex have been identified in several cancers. Understanding the functional significance of these alterations may have relevant implications for patient classification, risk prediction, and choice of treatment. Moreover, identification of vulnerabilities in cancer cells harboring cohesin mutations may provide new therapeutic opportunities and guide the design of personalized treatments.
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Affiliation(s)
- Magali De Koninck
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Ana Losada
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
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37
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Skibbens RV. Of Rings and Rods: Regulating Cohesin Entrapment of DNA to Generate Intra- and Intermolecular Tethers. PLoS Genet 2016; 12:e1006337. [PMID: 27788133 PMCID: PMC5082857 DOI: 10.1371/journal.pgen.1006337] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The clinical relevance of cohesin in DNA repair, tumorigenesis, and severe birth defects continues to fuel efforts in understanding cohesin structure, regulation, and enzymology. Early models depicting huge cohesin rings that entrap two DNA segments within a single lumen are fading into obscurity based on contradictory findings, but elucidating cohesin structure amid a myriad of functions remains challenging. Due in large part to integrated uses of a wide range of methodologies, recent advances are beginning to cast light into the depths that previously cloaked cohesin structure. Additional efforts similarly provide new insights into cohesin enzymology: specifically, the discoveries of ATP-dependent transitions that promote cohesin binding and release from DNA. In combination, these efforts posit a new model that cohesin exists primarily as a relatively flattened structure that entraps only a single DNA molecule and that subsequent ATP hydrolysis, acetylation, and oligomeric assembly tether together individual DNA segments.
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Affiliation(s)
- Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
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38
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Abstract
Each time a cell duplicates, the whole genome must be accurately copied and distributed. The enormous amount of DNA in eukaryotic cells requires a high level of coordination between polymerases and other DNA and chromatin-interacting proteins to ensure timely and accurate DNA replication and chromatin formation. PCNA forms a ring that encircles the DNA. It serves as a processivity factor for DNA polymerases and as a landing platform for different proteins that interact with DNA and chromatin. It thus serves as a signaling hub and influences the rate and accuracy of DNA replication, the r-formation of chromatin in the wake of the moving fork and the proper segregation of the sister chromatids. Four different, conserved, protein complexes are in charge of loading/unloading PCNA and similar molecules onto DNA. Replication factor C (RFC) is the canonical complex in charge of loading PCNA, the replication clamp, during S-phase. The Rad24, Ctf18 and Elg1 proteins form complexes similar to RFC, with particular functions in the cell's nucleus. Here we summarize our current knowledge about the roles of these important factors in yeast.
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Affiliation(s)
- Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
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39
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Shwartz M, Matityahu A, Onn I. Identification of Functional Domains in the Cohesin Loader Subunit Scc4 by a Random Insertion/Dominant Negative Screen. G3 (BETHESDA, MD.) 2016; 6:2655-63. [PMID: 27280786 PMCID: PMC4978918 DOI: 10.1534/g3.116.031674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/02/2016] [Indexed: 11/18/2022]
Abstract
Cohesin is a multi-subunit complex that plays an essential role in genome stability. Initial association of cohesin with chromosomes requires the loader-a heterodimer composed of Scc4 and Scc2 However, very little is known about the loader's mechanism of action. In this study, we performed a genetic screen to identify functional domains in the Scc4 subunit of the loader. We isolated scc4 mutant alleles that, when overexpressed, have a dominant negative effect on cell viability. We defined a small region in the N terminus of Scc4 that is dominant negative when overexpressed, and on which Scc2/Scc4 activity depends. When the mutant alleles are expressed as a single copy, they are recessive and do not support cell viability, cohesion, cohesin loading or Scc4 chromatin binding. In addition, we show that the mutants investigated reduce, but do not eliminate, the interaction of Scc4 with either Scc2 or cohesin. However, we show that Scc4 cannot bind cohesin in the absence of Scc2 Our results provide new insight into the roles of Scc4 in cohesin loading, and contribute to deciphering the loading mechanism.
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Affiliation(s)
- Michal Shwartz
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, 1311502, Israel
| | - Avi Matityahu
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, 1311502, Israel
| | - Itay Onn
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, 1311502, Israel
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Orgil O, Mor H, Matityahu A, Onn I. Identification of a region in the coiled-coil domain of Smc3 that is essential for cohesin activity. Nucleic Acids Res 2016; 44:6309-17. [PMID: 27307603 PMCID: PMC5291275 DOI: 10.1093/nar/gkw539] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 05/30/2016] [Accepted: 06/03/2016] [Indexed: 12/22/2022] Open
Abstract
The cohesin complex plays an important role in sister chromatin cohesion. Cohesin's core is composed of two structural maintenance of chromosome (SMC) proteins, called Smc1 and Smc3. SMC proteins are built from a globular hinge domain, a rod-shaped domain composed of long anti-parallel coiled-coil (CC), and a second globular adenosine triphosphatase domain called the head. The functions of both head and hinge domains have been studied extensively, yet the function of the CC region remains elusive. We identified a mutation in the CC of smc3 (L217P) that disrupts the function of the protein. Cells carrying the smc3-L217P allele have a strong cohesion defect and complexes containing smc3-L217P are not loaded onto the chromosomes. However, the mutation does not affect inter-protein interactions in either the core complex or with the Scc2 loader. We show by molecular dynamics and biochemistry that wild-type Smc3 can adopt distinct conformations, and that adenosine triphosphate (ATP) induces the conformational change. The L217P mutation restricts the ability of the mutated protein to switch between the conformations. We suggest that the function of the CC is to transfer ATP binding/hydrolysis signals between the head and the hinge domains. The results provide a new insight into the mechanism of cohesin activity.
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Affiliation(s)
- Ola Orgil
- Faculty of Medicine in The Galilee, Bar-Ilan University, 8 Henrietta Szold Street, P.O. Box 1589, Safed 1311502, Israel
| | - Hadar Mor
- Faculty of Medicine in The Galilee, Bar-Ilan University, 8 Henrietta Szold Street, P.O. Box 1589, Safed 1311502, Israel
| | - Avi Matityahu
- Faculty of Medicine in The Galilee, Bar-Ilan University, 8 Henrietta Szold Street, P.O. Box 1589, Safed 1311502, Israel
| | - Itay Onn
- Faculty of Medicine in The Galilee, Bar-Ilan University, 8 Henrietta Szold Street, P.O. Box 1589, Safed 1311502, Israel
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Ward A, Hopkins J, Mckay M, Murray S, Jordan PW. Genetic Interactions Between the Meiosis-Specific Cohesin Components, STAG3, REC8, and RAD21L. G3 (BETHESDA, MD.) 2016; 6:1713-24. [PMID: 27172213 PMCID: PMC4889667 DOI: 10.1534/g3.116.029462] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/05/2016] [Indexed: 11/21/2022]
Abstract
Cohesin is an essential structural component of chromosomes that ensures accurate chromosome segregation during mitosis and meiosis. Previous studies have shown that there are cohesin complexes specific to meiosis, required to mediate homologous chromosome pairing, synapsis, recombination, and segregation. Meiosis-specific cohesin complexes consist of two structural maintenance of chromosomes proteins (SMC1α/SMC1β and SMC3), an α-kleisin protein (RAD21, RAD21L, or REC8), and a stromal antigen protein (STAG1, 2, or 3). STAG3 is exclusively expressed during meiosis, and is the predominant STAG protein component of cohesin complexes in primary spermatocytes from mouse, interacting directly with each α-kleisin subunit. REC8 and RAD21L are also meiosis-specific cohesin components. Stag3 mutant spermatocytes arrest in early prophase ("zygotene-like" stage), displaying failed homolog synapsis and persistent DNA damage, as a result of unstable loading of cohesin onto the chromosome axes. Interestingly, Rec8, Rad21L double mutants resulted in an earlier "leptotene-like" arrest, accompanied by complete absence of STAG3 loading. To assess genetic interactions between STAG3 and α-kleisin subunits RAD21L and REC8, our lab generated Stag3, Rad21L, and Stag3, Rec8 double knockout mice, and compared them to the Rec8, Rad21L double mutant. These double mutants are phenotypically distinct from one another, and more severe than each single knockout mutant with regards to chromosome axis formation, cohesin loading, and sister chromatid cohesion. The Stag3, Rad21L, and Stag3, Rec8 double mutants both progress further into prophase I than the Rec8, Rad21L double mutant. Our genetic analysis demonstrates that cohesins containing STAG3 and REC8 are the main complex required for centromeric cohesion, and RAD21L cohesins are required for normal clustering of pericentromeric heterochromatin. Furthermore, the STAG3/REC8 and STAG3/RAD21L cohesins are the primary cohesins required for axis formation.
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Affiliation(s)
- Ayobami Ward
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Jessica Hopkins
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | | | | | - Philip W Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
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Woodman J, Hoffman M, Dzieciatkowska M, Hansen KC, Megee PC. Phosphorylation of the Scc2 cohesin deposition complex subunit regulates chromosome condensation through cohesin integrity. Mol Biol Cell 2015; 26:3754-67. [PMID: 26354421 PMCID: PMC4626061 DOI: 10.1091/mbc.e15-03-0165] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/27/2015] [Accepted: 09/04/2015] [Indexed: 01/19/2023] Open
Abstract
The cohesion of replicated sister chromatids promotes chromosome biorientation, gene regulation, DNA repair, and chromosome condensation. Cohesion is mediated by cohesin, which is deposited on chromosomes by a separate conserved loading complex composed of Scc2 and Scc4 in Saccharomyces cerevisiae. Although it is known to be required, the role of Scc2/Scc4 in cohesin deposition remains enigmatic. Scc2 is a phosphoprotein, although the functions of phosphorylation in deposition are unknown. We identified 11 phosphorylated residues in Scc2 by mass spectrometry. Mutants of SCC2 with substitutions that mimic constitutive phosphorylation retain normal Scc2-Scc4 interactions and chromatin association but exhibit decreased viability, sensitivity to genotoxic agents, and decreased stability of the Mcd1 cohesin subunit in mitotic cells. Cohesin association on chromosome arms, but not pericentromeric regions, is reduced in the phosphomimetic mutants but remains above a key threshold, as cohesion is only modestly perturbed. However, these scc2 phosphomimetic mutants exhibit dramatic chromosome condensation defects that are likely responsible for their high inviability. From these data, we conclude that normal Scc2 function requires modulation of its phosphorylation state and suggest that scc2 phosphomimetic mutants cause an increased incidence of abortive cohesin deposition events that result in compromised cohesin complex integrity and Mcd1 turnover.
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Affiliation(s)
- Julie Woodman
- Molecular Biology Program, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Matthew Hoffman
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Paul C Megee
- Molecular Biology Program, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
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Tong K, Skibbens RV. Pds5 regulators segregate cohesion and condensation pathways in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2015; 112:7021-6. [PMID: 25986377 PMCID: PMC4460518 DOI: 10.1073/pnas.1501369112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cohesins are required both for the tethering together of sister chromatids (termed cohesion) and subsequent condensation into discrete structures-processes fundamental for faithful chromosome segregation into daughter cells. Differentiating between cohesin roles in cohesion and condensation would provide an important advance in studying chromatin metabolism. Pds5 is a cohesin-associated factor that is essential for both cohesion maintenance and condensation. Recent studies revealed that ELG1 deletion suppresses the temperature sensitivity of pds5 mutant cells. However, the mechanisms through which Elg1 may regulate cohesion and condensation remain unknown. Here, we report that ELG1 deletion from pds5-1 mutant cells results in a significant rescue of cohesion, but not condensation, defects. Based on evidence that Elg1 unloads the DNA replication clamp PCNA from DNA, we tested whether PCNA overexpression would similarly rescue pds5-1 mutant cell cohesion defects. The results indeed reveal that elevated levels of PCNA rescue pds5-1 temperature sensitivity and cohesion defects, but do not rescue pds5-1 mutant cell condensation defects. In contrast, RAD61 deletion rescues the condensation defect, but importantly, neither the temperature sensitivity nor cohesion defects exhibited by pds5-1 mutant cells. In combination, these findings reveal that cohesion and condensation are separable pathways and regulated in nonredundant mechanisms. These results are discussed in terms of a new model through which cohesion and condensation are spatially regulated.
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Affiliation(s)
- Kevin Tong
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Robert V Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
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