1
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Benchorin G, Cho RJ, Li MJ, Molotkova N, Kohwi M. Dan forms condensates in neuroblasts and regulates nuclear architecture and progenitor competence in vivo. Nat Commun 2024; 15:5097. [PMID: 38877037 PMCID: PMC11178893 DOI: 10.1038/s41467-024-49326-6] [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: 01/22/2024] [Accepted: 05/30/2024] [Indexed: 06/16/2024] Open
Abstract
Genome organization is thought to underlie cell type specific gene expression, yet how it is regulated in progenitors to produce cellular diversity is unknown. In Drosophila, a developmentally-timed genome reorganization in neural progenitors terminates competence to produce early-born neurons. These events require downregulation of Distal antenna (Dan), part of the conserved pipsqueak DNA-binding superfamily. Here we find that Dan forms liquid-like condensates with high protein mobility, and whose size and subnuclear distribution are balanced with its DNA-binding. Further, we identify a LARKS domain, a structural motif associated with condensate-forming proteins. Deleting just 13 amino acids from LARKS abrogates Dan's ability to retain the early-born neural fate gene, hunchback, in the neuroblast nuclear interior and maintain competence in vivo. Conversely, domain-swapping with LARKS from known phase-separating proteins rescues Dan's effects on competence. Together, we provide in vivo evidence for condensate formation and the regulation of progenitor nuclear architecture underlying neuronal diversification.
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Affiliation(s)
- Gillie Benchorin
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Richard Jangwon Cho
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Maggie Jiaqi Li
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Natalia Molotkova
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Minoree Kohwi
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
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2
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Valyaeva AA, Sheval EV. Nonspecific Interactions in Transcription Regulation and Organization of Transcriptional Condensates. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:688-700. [PMID: 38831505 DOI: 10.1134/s0006297924040084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/19/2023] [Accepted: 11/20/2023] [Indexed: 06/05/2024]
Abstract
Eukaryotic cells are characterized by a high degree of compartmentalization of their internal contents, which ensures precise and controlled regulation of intracellular processes. During many processes, including different stages of transcription, dynamic membraneless compartments termed biomolecular condensates are formed. Transcription condensates contain various transcription factors and RNA polymerase and are formed by high- and low-specificity interactions between the proteins, DNA, and nearby RNA. This review discusses recent data demonstrating important role of nonspecific multivalent protein-protein and RNA-protein interactions in organization and regulation of transcription.
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Affiliation(s)
- Anna A Valyaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia.
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
- Department of Cell Biology and Histology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Eugene V Sheval
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
- Department of Cell Biology and Histology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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3
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Potapova TA, Unruh JR, Conkright-Fincham J, Banks CAS, Florens L, Schneider DA, Gerton JL. Distinct states of nucleolar stress induced by anticancer drugs. eLife 2023; 12:RP88799. [PMID: 38099650 PMCID: PMC10723795 DOI: 10.7554/elife.88799] [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: 12/17/2023] Open
Abstract
Ribosome biogenesis is a vital and highly energy-consuming cellular function occurring primarily in the nucleolus. Cancer cells have an elevated demand for ribosomes to sustain continuous proliferation. This study evaluated the impact of existing anticancer drugs on the nucleolus by screening a library of anticancer compounds for drugs that induce nucleolar stress. For a readout, a novel parameter termed 'nucleolar normality score' was developed that measures the ratio of the fibrillar center and granular component proteins in the nucleolus and nucleoplasm. Multiple classes of drugs were found to induce nucleolar stress, including DNA intercalators, inhibitors of mTOR/PI3K, heat shock proteins, proteasome, and cyclin-dependent kinases (CDKs). Each class of drugs induced morphologically and molecularly distinct states of nucleolar stress accompanied by changes in nucleolar biophysical properties. In-depth characterization focused on the nucleolar stress induced by inhibition of transcriptional CDKs, particularly CDK9, the main CDK that regulates RNA Pol II. Multiple CDK substrates were identified in the nucleolus, including RNA Pol I- recruiting protein Treacle, which was phosphorylated by CDK9 in vitro. These results revealed a concerted regulation of RNA Pol I and Pol II by transcriptional CDKs. Our findings exposed many classes of chemotherapy compounds that are capable of inducing nucleolar stress, and we recommend considering this in anticancer drug development.
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Affiliation(s)
| | - Jay R Unruh
- Stowers Institute for Medical ResearchKansas CityUnited States
| | | | | | | | - David Alan Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Jennifer L Gerton
- Stowers Institute for Medical ResearchKansas CityUnited States
- Department of Biochemistry and Molecular Biology, University of Kansas Medical CenterKansas CityUnited States
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4
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Castillon GA, Phan S, Hu J, Boassa D, Adams SR, Ellisman MH. Proximal Molecular Probe Transfer (PROMPT), a new approach for identifying sites of protein/nucleic acid interaction in cells by correlated light and electron microscopy. Sci Rep 2023; 13:21462. [PMID: 38052818 PMCID: PMC10697944 DOI: 10.1038/s41598-023-45413-8] [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: 08/16/2023] [Accepted: 10/19/2023] [Indexed: 12/07/2023] Open
Abstract
The binding and interaction of proteins with nucleic acids such as DNA and RNA constitutes a fundamental biochemical and biophysical process in all living organisms. Identifying and visualizing such temporal interactions in cells is key to understanding their function. To image sites of these events in cells across scales, we developed a method, named PROMPT for PROximal Molecular Probe Transfer, which is applicable to both light and correlative electron microscopy. This method relies on the transfer of a bound photosensitizer from a protein known to associate with specific nucleic acid sequence, allowing the marking of the binding site on DNA or RNA in fixed cells. The method produces a fluorescent mark at the site of their interaction, that can be made electron dense and reimaged at high resolution in the electron microscope. As proof of principle, we labeled in situ the interaction sites between the histone H2B and nuclear DNA. As an example of application for specific RNA localizations we labeled different nuclear and nucleolar fractions of the protein Fibrillarin to mark and locate where it associates with RNAs, also using electron tomography. While the current PROMPT method is designed for microscopy, with minimal variations, it can be potentially expanded to analytical techniques.
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Affiliation(s)
- Guillaume A Castillon
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Sebastien Phan
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Junru Hu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Daniela Boassa
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Stephen R Adams
- Department of Pharmacology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Mark H Ellisman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA.
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA, 92093, USA.
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5
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Kour R, Kim J, Roy A, Richardson B, Cameron MJ, Knott JG, Mazumder B. Loss of function of ribosomal protein L13a blocks blastocyst formation and reveals a potential nuclear role in gene expression. FASEB J 2023; 37:e23275. [PMID: 37902531 PMCID: PMC10999073 DOI: 10.1096/fj.202301475r] [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: 07/18/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 10/31/2023]
Abstract
Ribosomal proteins play diverse roles in development and disease. Most ribosomal proteins have canonical roles in protein synthesis, while some exhibit extra-ribosomal functions. Previous studies in our laboratory revealed that ribosomal protein L13a (RPL13a) is involved in the translational silencing of a cohort of inflammatory proteins in myeloid cells. This prompted us to investigate the role of RPL13a in embryonic development. Here we report that RPL13a is required for early development in mice. Crosses between Rpl13a+/- mice resulted in no Rpl13a-/- offspring. Closer examination revealed that Rpl13a-/- embryos were arrested at the morula stage during preimplantation development. RNA sequencing analysis of Rpl13a-/- morulae revealed widespread alterations in gene expression, including but not limited to several genes encoding proteins involved in the inflammatory response, embryogenesis, oocyte maturation, stemness, and pluripotency. Ex vivo analysis revealed that RPL13a was localized to the cytoplasm and nucleus between the two-cell and morula stages. RNAi-mediated depletion of RPL13a phenocopied Rpl13a-/- embryos and knockdown embryos exhibited increased expression of IL-7 and IL-17 and decreased expression of the lineage specifier genes Sox2, Pou5f1, and Cdx2. Lastly, a protein-protein interaction assay revealed that RPL13a is associated with chromatin, suggesting an extra ribosomal function in transcription. In summary, our data demonstrate that RPL13a is essential for the completion of preimplantation embryo development. The mechanistic basis of the absence of RPL13a-mediated embryonic lethality will be addressed in the future through follow-up studies on ribosome biogenesis, global protein synthesis, and identification of RPL13a target genes using chromatin immunoprecipitation and RNA-immunoprecipitation-based sequencing.
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Affiliation(s)
- Ravinder Kour
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
| | - Jaehwan Kim
- Developmental Epigenetics Laboratory, Department of Animal Science, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, Michigan, USA
| | - Antara Roy
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
| | - Brian Richardson
- Department of Population and Quantitative Health Sciences, Institute for Computational Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mark J. Cameron
- Department of Population and Quantitative Health Sciences, Institute for Computational Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jason G. Knott
- Developmental Epigenetics Laboratory, Department of Animal Science, Reproductive and Developmental Sciences Program, Michigan State University, East Lansing, Michigan, USA
| | - Barsanjit Mazumder
- Center for Gene Regulation in Health and Disease, Department of Biological Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA
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6
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Duan D, Lyu W, Chai P, Ma S, Wu K, Wu C, Xiong Y, Sestan N, Zhang K, Koleske AJ. Abl2 repairs microtubules and phase separates with tubulin to promote microtubule nucleation. Curr Biol 2023; 33:4582-4598.e10. [PMID: 37858340 PMCID: PMC10877310 DOI: 10.1016/j.cub.2023.09.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 07/07/2023] [Accepted: 09/06/2023] [Indexed: 10/21/2023]
Abstract
Abl family kinases are evolutionarily conserved regulators of cell migration and morphogenesis. Genetic experiments in Drosophila suggest that Abl family kinases interact functionally with microtubules to regulate axon guidance and neuronal morphogenesis. Vertebrate Abl2 binds to microtubules and promotes their plus-end elongation, both in vitro and in cells, but the molecular mechanisms by which Abl2 regulates microtubule (MT) dynamics are unclear. We report here that Abl2 regulates MT assembly via condensation and direct interactions with both the MT lattice and tubulin dimers. We find that Abl2 promotes MT nucleation, which is further facilitated by the ability of the Abl2 C-terminal half to undergo liquid-liquid phase separation (LLPS) and form co-condensates with tubulin. Abl2 binds to regions adjacent to MT damage, facilitates MT repair via fresh tubulin recruitment, and increases MT rescue frequency and lifetime. Cryo-EM analyses strongly support a model in which Abl2 engages tubulin C-terminal tails along an extended MT lattice conformation at damage sites to facilitate repair via fresh tubulin recruitment. Abl2Δ688-790, which closely mimics a naturally occurring splice isoform, retains binding to the MT lattice but does not bind tubulin, promote MT nucleation, or increase rescue frequency. In COS-7 cells, MT reassembly after nocodazole treatment is greatly slowed in Abl2 knockout COS-7 cells compared with wild-type cells, and these defects are rescued by re-expression of Abl2, but not Abl2Δ688-790. We propose that Abl2 locally concentrates tubulin to promote MT nucleation and recruits it to defects in the MT lattice to enable repair and rescue.
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Affiliation(s)
- Daisy Duan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Wanqing Lyu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Pengxin Chai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Shaojie Ma
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA
| | - Kuanlin Wu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Chunxiang Wu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Nenad Sestan
- Department of Neuroscience, Yale University, New Haven, CT 06510, USA; Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA; Department of Psychiatry, Yale School of Medicine, New Haven, CT 06510, USA; Department of Comparative Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, CT 06510, USA; Yale Child Study Center, Yale School of Medicine, New Haven, CT 06510, USA
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Anthony J Koleske
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA; Department of Neuroscience, Yale University, New Haven, CT 06510, USA.
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7
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Wang C, Ma H, Baserga SJ, Pederson T, Huang S. Nucleolar structure connects with global nuclear organization. Mol Biol Cell 2023; 34:ar114. [PMID: 37610836 PMCID: PMC10846622 DOI: 10.1091/mbc.e23-02-0062] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/25/2023] Open
Abstract
The nucleolus is a multifunctional nuclear body. To tease out the roles of nucleolar structure without resorting to the use of multi-action drugs, we knocked down the RNA polymerase I subunit RPA194 in HeLa cells by siRNA. Loss of RPA194 resulted in nucleolar-structural segregation and effects on both nucleolus-proximal and distal-nuclear components. The perinucleolar compartment was disrupted, centromere clustering around nucleoli was significantly reduced, and the intranuclear locations of specific genomic loci were altered. Moreover, Cajal bodies, distal from nucleoli, underwent morphological and some compositional changes. In comparison, when the preribosomal RNA-processing factor, UTP4, was knocked down, neither nucleolar segregation nor the intranuclear effects were observed, demonstrating that the changes of nucleolar proximal and distal nuclear domains in RPA194 knockdown cells unlikely arise from a cessation of ribosome synthesis, rather from the consequence of nucleolar-structure alteration. These findings point to a commutative system that links nucleolar structure to the maintenance and spatial organization of certain nuclear domains and genomic loci.
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Affiliation(s)
- Chen Wang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Hanhui Ma
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Susan J. Baserga
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Thoru Pederson
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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8
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Okuwaki M, Ozawa SI, Ebine S, Juichi M, Umeki T, Niioka K, Kikuchi T, Tanaka N. The stability of NPM1 oligomers regulated by acidic disordered regions controls the quality of liquid droplets. J Biochem 2023; 174:461-476. [PMID: 37540843 DOI: 10.1093/jb/mvad061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023] Open
Abstract
The nucleolus is a membrane-less nuclear body that typically forms through the process of liquid-liquid phase separation (LLPS) involving its components. NPM1 drives LLPS within the nucleolus and its oligomer formation and inter-oligomer interactions play a cooperative role in inducing LLPS. However, the molecular mechanism underlaying the regulation of liquid droplet quality formed by NPM1 remains poorly understood. In this study, we demonstrate that the N-terminal and central acidic residues within the intrinsically disordered regions (IDR) of NPM1 contribute to attenuating oligomer stability, although differences in the oligomer stability were observed only under stringent conditions. Furthermore, the impact of the IDRs is augmented by an increase in net negative charges resulting from phosphorylation within the IDRs. Significantly, we observed an increase in fluidity of liquid droplets formed by NPM1 with decreased oligomer stability. These results indicate that the difference in oligomer stability only observed biochemically under stringent conditions has a significant impact on liquid droplet quality formed by NPM1. Our findings provide new mechanistic insights into the regulation of nucleolar dynamics during the cell cycle.
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Affiliation(s)
- Mitsuru Okuwaki
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Shin-Ichiro Ozawa
- Laboratory of Physical Chemistry for Drug Design, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Shuhei Ebine
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Motoki Juichi
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Tadanobu Umeki
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Kazuki Niioka
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Taiyo Kikuchi
- Laboratory of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
| | - Nobutada Tanaka
- Laboratory of Physical Chemistry for Drug Design, School of Pharmacy, Kitasato University, 5-9-1, Shirokane, Minato-Ku, 108-8641 Tokyo, Japan
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9
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Castillon GA, Phan S, Hu J, Boassa D, Adams SR, Ellisman MH. Proximal Molecular Probe Transfer (PROMPT), a new approach for identifying sites of protein/nucleic acid interaction in cells by correlated light and electron microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542936. [PMID: 37808832 PMCID: PMC10557592 DOI: 10.1101/2023.05.30.542936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
The binding and interaction of proteins with nucleic acids such as DNA and RNA constitutes a fundamental biochemical and biophysical process in all living organisms. Identifying and visualizing such temporal interactions in cells is key to understanding their function. To image sites of these events in cells across scales, we developed a method, named PROMPT for PROximal Molecular Probe Transfer, which is applicable to both light and correlative electron microscopy. This method relies on the transfer of a bound photosensitizer from a protein known to associate with specific nucleic acid sequence, allowing the marking of the binding site on DNA or RNA in fixed cells. The method produces a fluorescent mark at the site of their interaction, that can be made electron dense and reimaged at high resolution in the electron microscope. As proof of principle, we labeled in situ the interaction sites between the histone H2B and nuclear DNA. As an example of application for specific RNA localizations we labeled different nuclear and nucleolar fractions of the protein Fibrillarin to mark and locate where it associates with RNAs, also using electron tomography. While the current PROMPT method is designed for microscopy, with minimal variations, it can be potentially expanded to analytical techniques.
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10
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Cho MJ, Kim CE, Shin YH, Kim JK, Pack CG. Influence of Chemical and Genetic Manipulations on Cellular Organelles Quantified by Label-Free Optical Diffraction Tomography. Anal Chem 2023; 95:13478-13487. [PMID: 37523497 DOI: 10.1021/acs.analchem.3c01349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Label-free optical diffraction tomography provides three-dimensional imaging of cells and organelles, along with their refractive index (RI) and volume. These physical parameters are valuable for quantitative and accurate analysis of the subcellular microenvironment and its connections to intracellular biological properties. In biological and biochemical cell analysis, various invasive cell manipulations are used, such as temperature change, chemical fixation, live cell staining with fluorescent dye, and gene overexpression of exogenous proteins. However, it is not fully understood how these various manipulations affect the physicochemical properties of different organelles. In this study, we investigated the impact of these manipulations on the cellular properties of single HeLa cells. We found that after cell fixation and an increase in temperature, the RI value of organelles, such as the nucleus and cytoplasm, significantly decreased overall. Interestingly, unlike the cell nuclei, cytoplasmic RI values were hardly detected after membrane permeation, indicating that only intracytoplasmic components were largely lost. Additionally, our findings revealed that the expression of GFP and GFP-tagged proteins significantly increased the RI values of organelles in living cells compared to the less effective RI changes observed with chemical fluorescence staining for cell organelles. The result demonstrates that distinct types of invasive manipulations can alter the microenvironment of organelles in different ways. Our study sheds new light on how chemical and genetic manipulations affect organelles.
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Affiliation(s)
- Min Ju Cho
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Chae-Eun Kim
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Yeon Hui Shin
- Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Jun Ki Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Republic of Korea
- Department of Biomedical Engineering, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Chan-Gi Pack
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Republic of Korea
- Department of Biomedical Engineering, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
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11
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Hertzog M, Erdel F. The Material Properties of the Cell Nucleus: A Matter of Scale. Cells 2023; 12:1958. [PMID: 37566037 PMCID: PMC10416959 DOI: 10.3390/cells12151958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 08/12/2023] Open
Abstract
Chromatin regulatory processes physically take place in the environment of the cell nucleus, which is filled with the chromosomes and a plethora of smaller biomolecules. The nucleus contains macromolecular assemblies of different sizes, from nanometer-sized protein complexes to micrometer-sized biomolecular condensates, chromosome territories, and nuclear bodies. This multiscale organization impacts the transport processes within the nuclear interior, the global mechanical properties of the nucleus, and the way the nucleus senses and reacts to mechanical stimuli. Here, we discuss recent work on these aspects, including microrheology and micromanipulation experiments assessing the material properties of the nucleus and its subcomponents. We summarize how the properties of multiscale media depend on the time and length scales probed in the experiment, and we reconcile seemingly contradictory observations made on different scales. We also revisit the concept of liquid-like and solid-like material properties for complex media such as the nucleus. We propose that the nucleus can be considered a multiscale viscoelastic medium composed of three major components with distinct properties: the lamina, the chromatin network, and the nucleoplasmic fluid. This multicomponent organization enables the nucleus to serve its different functions as a reaction medium on the nanoscale and as a mechanosensor and structural scaffold on the microscale.
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Affiliation(s)
| | - Fabian Erdel
- MCD, Center for Integrative Biology (CBI), University of Toulouse, CNRS, 169 Avenue Marianne Grunberg-Manago, 31062 Toulouse, France
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12
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Wang C, Ma H, Baserga SJ, Pederson T, Huang S. Nucleolar structure connects with global nuclear organization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534966. [PMID: 37034708 PMCID: PMC10081344 DOI: 10.1101/2023.03.30.534966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The nucleolus is a multi-functional nuclear body. To tease out the roles of nucleolar structure without resorting to multi-action drugs, we knocked down RNA polymerase I subunit RPA194 in HeLa cells by siRNA. Loss of RPA194 resulted in nucleolar structural segregation and effects on both nucleolus-proximal and distal nuclear components. The perinucleolar compartment was disrupted, centromere-nucleolus interactions were significantly reduced, and the intranuclear locations of specific genomic loci were altered. Moreover, Cajal bodies, distal from nucleoli, underwent morphological and compositional changes. To distinguish whether these global reorganizations are the results of nucleolar structural disruption or inhibition of ribosome synthesis, the pre-ribosomal RNA processing factor, UTP4, was also knocked down, which did not lead to nucleolar segregation, nor the intranuclear effects seen with RPA195A knockdown, demonstrating that they do not arise from a cessation of ribosome synthesis. These findings point to a commutative system that links nucleolar structure to the maintenance and spatial organization of certain nuclear bodies and genomic loci.
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Affiliation(s)
- Chen Wang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Hanhui Ma
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - Susan J Baserga
- Department of Genetics, Yale School of Medicine, New Haven, CT
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
| | - Thoru Pederson
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL
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13
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Decle-Carrasco S, Rodríguez-Piña AL, Rodríguez-Zapata LC, Castano E. Current research on viral proteins that interact with fibrillarin. Mol Biol Rep 2023; 50:4631-4643. [PMID: 36928641 PMCID: PMC10018631 DOI: 10.1007/s11033-023-08343-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/15/2023] [Indexed: 03/18/2023]
Abstract
The nucleolus is a multifunctional nuclear domain primarily dedicated to ribosome biogenesis. Certain viruses developed strategies to manipulate host nucleolar proteins to facilitate their replication by modulating ribosomal RNA (rRNA) processing. This association interferes with nucleolar functions resulting in overactivation or arrest of ribosome biogenesis, induction or inhibition of apoptosis, and affecting stress response. The nucleolar protein fibrillarin (FBL) is an important target of some plant and animal viruses. FBL is an essential and highly conserved S-adenosyl methionine (SAM) dependent methyltransferase, capable of rRNA degradation by its intrinsically disordered region (IDR), the glycine/arginine-rich (GAR) domain. It forms a ribonucleoprotein complex that directs 2'-O-methylations in more than 100 sites of pre-rRNAs. It is involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. The interaction with animal viruses, including human viruses, triggered its redistribution to the nucleoplasm and cytoplasm, interfering with its role in pre-rRNA processing. Viral-encoded proteins with IDRs as nucleocapsids, matrix, Tat protein, and even a viral snoRNA, can associate with FBL, forcing the nucleolar protein to undergo atypical functions. Here we review the molecular mechanisms employed by animal and human viruses to usurp FBL functions and the effect on cellular processes, particularly in ribosome biogenesis.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Alma Laura Rodríguez-Piña
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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14
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Che X, Wu J, Liu H, Su J, Chen X. Cellular liquid-liquid phase separation: Concept, functions, regulations, and detections. J Cell Physiol 2023; 238:847-865. [PMID: 36870067 DOI: 10.1002/jcp.30980] [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: 06/06/2022] [Revised: 10/05/2022] [Accepted: 02/08/2023] [Indexed: 03/06/2023]
Abstract
Liquid-liquid phase separation is a multicomponent system separated into phases with different compositions and structures. It has been identified and explored in organisms after being introduced from the thermodynamic field. Condensate, the product of phase separation, exists in different scales of cellular structures, such as nucleolus, stress granules, and other organelles in nuclei or cytoplasm. And also play critical roles in different cellular behaviors. Here, we review the concept, thermodynamical and biochemical principles of phase separation. We summarized the main functions including the adjustment of biochemical reaction rates, the regulation of macromolecule folding state, subcellular structural support, the mediation of subcellular location, and intimately linked to different kinds of diseases, such as cancer and neurodegeneration. Advanced detection methods to investigate phase separation are collected and analyzed. We conclude with the discussion of anxiety of phase separation, and thought about how progress can be made to develop precise detection methods and disclose the potential application of condensates.
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Affiliation(s)
- Xuanlin Che
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Changsha, Hunan, China.,Hunan Engineering Research Center of Skin Health and Disease, Xiangya Hospital, Changsha, Hunan, China.,Xiangya Clinical Research Center for Cancer Immunotherapy, Central South University, Changsha, Hunan, China
| | - Jiajun Wu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China
| | - Hua Liu
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China
| | - Juan Su
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Changsha, Hunan, China.,Hunan Engineering Research Center of Skin Health and Disease, Xiangya Hospital, Changsha, Hunan, China.,Xiangya Clinical Research Center for Cancer Immunotherapy, Central South University, Changsha, Hunan, China
| | - Xiang Chen
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Changsha, Hunan, China.,Hunan Engineering Research Center of Skin Health and Disease, Xiangya Hospital, Changsha, Hunan, China.,Xiangya Clinical Research Center for Cancer Immunotherapy, Central South University, Changsha, Hunan, China
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15
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Girke P, Seufert W. Targeting of Hmo1 to subcompartments of the budding yeast nucleolus. Mol Biol Cell 2023; 34:ar22. [PMID: 36696177 PMCID: PMC10011721 DOI: 10.1091/mbc.e22-07-0261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The nucleolus is a multilayered, membraneless organelle made up of liquidlike biogenesis compartments surrounding an array of ribosomal RNA genes (rDNA). Biogenesis factors accumulate in the outer compartments through RNA binding and phase separation promoted by intrinsically disordered protein regions. In contrast, the nucleolar localization of rDNA-binding proteins, which reside in the central chromatin compartment, is less well characterized. To gain mechanistic insight, we analyzed the localization, mitotic segregation, nucleic acid binding, and nuclear dynamics of the budding yeast rDNA-binding protein Hmo1. Deletion of the main DNA-binding domain, the HMG boxB, compromised Hmo1 transfer to daughter cells in mitosis and transcription-independent rDNA association but still allowed nucleolar localization. The C-terminal lysine-rich region turned out to be a combined nuclear and nucleolar localization sequence (NLS-NoLS). Its integrity was required for maximal enrichment and efficient retention of Hmo1 in the nucleolus and nucleolar localization of the ΔboxB construct. Moreover, the NLS-NoLS region was sufficient to promote nucleolar accumulation and bound nucleic acids in vitro with some preference for RNA. Bleaching experiments indicated mobility of Hmo1 inside the nucleolus but little exchange with the nucleoplasm. Thus, a bilayered targeting mechanism secures proper localization of Hmo1 to the nucleolus.
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Affiliation(s)
- Philipp Girke
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Wolfgang Seufert
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
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16
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Sekar D, Tusubira D, Ross K. TDP-43 and NEAT long non-coding RNA: Roles in neurodegenerative disease. Front Cell Neurosci 2022; 16:954912. [PMID: 36385948 PMCID: PMC9650703 DOI: 10.3389/fncel.2022.954912] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/11/2022] [Indexed: 01/03/2023] Open
Abstract
Understanding and ameliorating neurodegenerative diseases represents a key challenge for supporting the health span of the aging population. Diverse protein aggregates have been implicated in such neurodegenerative disorders, including amyloid-β, α-synuclein, tau, fused in sarcoma (FUS), and transactivation response element (TAR) DNA-binding protein 43 (TDP-43). Recent years have seen significant growth in our mechanistic knowledge of relationships between these proteins and some of the membrane-less nuclear structures that fulfill key roles in the cell function. These include the nucleolus, nuclear speckles, and paraspeckles. The ability of macromolecular protein:RNA complexes to partition these nuclear condensates through biophysical processes that involve liquid-liquid phase separation (LLPS) has also gained attention recently. The paraspeckle, which is scaffolded by the architectural long-non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) plays central roles in RNA processing and metabolism and has been linked dynamically to TDP-43. In this mini-review, we outline essential early and recent insights in relation to TDP-43 proteinopathies. We then appraise the relationships between TDP-43 and NEAT1 in the context of neuronal paraspeckles and neuronal stress. We highlight key areas for investigation based on recent advances in our understanding of how TDP-43 affects neuronal function, especially in relation to messenger ribosomal nucleic acid (mRNA) splicing. Finally, we offer perspectives that should be considered for translational pipelines in order to improve health outcomes for the management of neurodegenerative diseases.
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Affiliation(s)
- Durairaj Sekar
- Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, India
| | - Deusdedit Tusubira
- Department of Biochemistry, Mbarara University of Science and Technology, Mbarara, Uganda,*Correspondence: Deusdedit Tusubira, ; orcid.org/0000-0002-4698-424X
| | - Kehinde Ross
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom,Institute for Health Research, Liverpool John Moores University, Liverpool, United Kingdom,Kehinde Ross, ; orcid.org/0000-0003-0252-1152
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17
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Lin S, Rajan S, Lemberg S, Altawil M, Anderson K, Bryant R, Cappeta S, Chin B, Hamdan I, Hamer A, Hyzny R, Karp A, Lee D, Lim A, Nayak M, Palaniappan V, Park S, Satishkumar S, Seth A, Sri Dasari U, Toppari E, Vyas A, Walker J, Weston E, Zafar A, Zielke C, Mahabeleshwar GH, Tartakoff AM. Production of nascent ribosome precursors within the nucleolar microenvironment of Saccharomyces cerevisiae. Genetics 2022; 221:iyac070. [PMID: 35657327 PMCID: PMC9252279 DOI: 10.1093/genetics/iyac070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
35S rRNA transcripts include a 5'-external transcribed spacer followed by rRNAs of the small and large ribosomal subunits. Their processing yields massive precursors that include dozens of assembly factor proteins. In Saccharomyces cerevisiae, nucleolar assembly factors form 2 coaxial layers/volumes around ribosomal DNA. Most of these factors are cyclically recruited from a latent state to an operative state, and are extensively conserved. The layers match, at least approximately, known subcompartments found in higher eukaryotic cells. ∼80% of assembly factors are essential. The number of copies of these assembly factors is comparable to the number of nascent transcripts. Moreover, they exhibit "isoelectric balance," with RNA-binding candidate "nucleator" assembly factors being notably basic. The physical properties of pre-small subunit and pre-large subunit assembly factors are similar, as are their 19 motif signatures detected by hierarchical clustering, unlike motif signatures of the 5'-external transcribed spacer rRNP. Additionally, many assembly factors lack shared motifs. Taken together with the progression of rRNP composition during subunit maturation, and the realization that the ribosomal DNA cable is initially bathed in a subunit-nonspecific assembly factor reservoir/microenvironment, we propose a "3-step subdomain assembly model": Step (1): predominantly basic assembly factors sequentially nucleate sites along nascent rRNA; Step (2): the resulting rRNPs recruit numerous less basic assembly factors along with notably basic ribosomal proteins; Step (3): rRNPs in nearby subdomains consolidate. Cleavages of rRNA then promote release of rRNPs to the nucleoplasm, likely facilitated by the persistence of assembly factors that were already associated with nucleolar precursors.
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Affiliation(s)
- Samantha Lin
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Suchita Rajan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sofia Lemberg
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Mark Altawil
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Katherine Anderson
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ruth Bryant
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sebastian Cappeta
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Brandon Chin
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Isabella Hamdan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Annelise Hamer
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Rachel Hyzny
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Andrew Karp
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Daniel Lee
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Alexandria Lim
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Medha Nayak
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Vishnu Palaniappan
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Soomin Park
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sarika Satishkumar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Anika Seth
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Uva Sri Dasari
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Emili Toppari
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ayush Vyas
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Julianne Walker
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Evan Weston
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Atif Zafar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Cecelia Zielke
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ganapati H Mahabeleshwar
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Alan M Tartakoff
- Pathology Department and The Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA
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18
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Abstract
The nucleolus is best known for housing the highly ordered assembly line that produces ribosomal subunits. The >100 ribosome assembly factors in the nucleolus are thought to cycle between two states: an operative state (when integrated into subunit assembly intermediates) and a latent state (upon release from intermediates). Although it has become commonplace to refer to the nucleolus as "being a multilayered condensate," and this may be accurate for latent factors, there is little reason to think that such assertions pertain to the operative state of assembly factors.
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Affiliation(s)
- Alan Tartakoff
- Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Patrick DiMario
- Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Eduard Hurt
- Universität Heidelberg, Biochemistry Center, Heidelberg, Baden Württemberg 69120, Germany
| | - Brian McStay
- Centre for Chromosome Biology, Galway H91 TK33, Ireland
| | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, Zurich CH-8057, Switzerland
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, Edinburgh EH9 3BF, United Kingdom
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19
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Lavering ED, Petros IN, Weeks DL. Component analysis of nucleolar protein compartments using Xenopus laevis oocytes. Dev Growth Differ 2022; 64:306-317. [PMID: 35607824 PMCID: PMC9474603 DOI: 10.1111/dgd.12794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/12/2022] [Accepted: 05/17/2022] [Indexed: 12/19/2022]
Abstract
The nucleolus is a multi‐compartment, non‐membrane‐bound organelle within the nucleus. Nucleolar assembly is influenced by proteins capable of phase separation. Xenopus laevis oocytes contain hundreds of large nucleoli that provide experimental access for nucleoli that is unavailable in other systems. Here we detail methods to streamline the in vivo analysis of the compartmentalization of nucleolar proteins that are suspected of phase separation. The nucleolus is the main hub of ribosome biogenesis and here we present data supporting the division of proteins into nucleolar domains based on their function in ribosome biogenesis. We also describe the use of vital dyes such as Hoechst 33342 and Thioflavin T in nucleolar staining. Additionally, we quantify nucleolar morphology changes induced by heat shock and actinomycin D treatments. We suggest these approaches will be valuable in a variety of studies that seek to better understand the nucleolus, particularly those regarding phase separation. These approaches may also be instructive for other studies on phase separation, especially in the nucleus.
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Affiliation(s)
- Emily D Lavering
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Irini N Petros
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Daniel L Weeks
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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20
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Cecchini NM, Torres JR, López IL, Cobo S, Nota F, Alvarez ME. Alternative splicing of an exitron determines the subnuclear localization of the Arabidopsis DNA glycosylase MBD4L under heat stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:377-388. [PMID: 35061303 DOI: 10.1111/tpj.15675] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Nicolás Miguel Cecchini
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - José Roberto Torres
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Ignacio Lescano López
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Santiago Cobo
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - Florencia Nota
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
| | - María Elena Alvarez
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, Argentina
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21
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Abstract
In eukaryotic cells, protein and RNA factors involved in genome activities like transcription, RNA processing, DNA replication, and repair accumulate in self-organizing membraneless chromatin subcompartments. These structures contribute to efficiently conduct chromatin-mediated reactions and to establish specific cellular programs. However, the underlying mechanisms for their formation are only partly understood. Recent studies invoke liquid-liquid phase separation (LLPS) of proteins and RNAs in the establishment of chromatin activity patterns. At the same time, the folding of chromatin in the nucleus can drive genome partitioning into spatially distinct domains. Here, the interplay between chromatin organization, chromatin binding, and LLPS is discussed by comparing and contrasting three prototypical chromatin subcompartments: the nucleolus, clusters of active RNA polymerase II, and pericentric heterochromatin domains. It is discussed how the different ways of chromatin compartmentalization are linked to transcription regulation, the targeting of soluble factors to certain parts of the genome, and to disease-causing genetic aberrations.
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Affiliation(s)
- Karsten Rippe
- Division of Chromatin Networks, German Cancer Research Center (DKFZ) and Bioquant, 69120 Heidelberg, Germany
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22
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Shin Y. Rich Phase Separation Behavior of Biomolecules. Mol Cells 2022; 45:6-15. [PMID: 34966005 PMCID: PMC8819493 DOI: 10.14348/molcells.2021.0204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/10/2021] [Accepted: 09/10/2021] [Indexed: 11/27/2022] Open
Abstract
Phase separation is a thermodynamic process leading to the formation of compositionally distinct phases. For the past few years, numerous works have shown that biomolecular phase separation serves as biogenesis mechanisms of diverse intracellular condensates, and aberrant phase transitions are associated with disease states such as neurodegenerative diseases and cancers. Condensates exhibit rich phase behaviors including multiphase internal structuring, noise buffering, and compositional tunability. Recent studies have begun to uncover how a network of intermolecular interactions can give rise to various biophysical features of condensates. Here, we review phase behaviors of biomolecules, particularly with regard to regular solution models of binary and ternary mixtures. We discuss how these theoretical frameworks explain many aspects of the assembly, composition, and miscibility of diverse biomolecular phases, and highlight how a model-based approach can help elucidate the detailed thermodynamic principle for multicomponent intracellular phase separation.
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Affiliation(s)
- Yongdae Shin
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul 08826, Korea
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23
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Dilworth D, Hanley RP, Ferreira de Freitas R, Allali-Hassani A, Zhou M, Mehta N, Marunde MR, Ackloo S, Carvalho Machado RA, Khalili Yazdi A, Owens DDG, Vu V, Nie DY, Alqazzaz M, Marcon E, Li F, Chau I, Bolotokova A, Qin S, Lei M, Liu Y, Szewczyk MM, Dong A, Kazemzadeh S, Abramyan T, Popova IK, Hall NW, Meiners MJ, Cheek MA, Gibson E, Kireev D, Greenblatt JF, Keogh MC, Min J, Brown PJ, Vedadi M, Arrowsmith CH, Barsyte-Lovejoy D, James LI, Schapira M. A chemical probe targeting the PWWP domain alters NSD2 nucleolar localization. Nat Chem Biol 2022; 18:56-63. [PMID: 34782742 PMCID: PMC9189931 DOI: 10.1038/s41589-021-00898-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/09/2021] [Indexed: 01/03/2023]
Abstract
Nuclear receptor-binding SET domain-containing 2 (NSD2) is the primary enzyme responsible for the dimethylation of lysine 36 of histone 3 (H3K36), a mark associated with active gene transcription and intergenic DNA methylation. In addition to a methyltransferase domain, NSD2 harbors two proline-tryptophan-tryptophan-proline (PWWP) domains and five plant homeodomains (PHDs) believed to serve as chromatin reading modules. Here, we report a chemical probe targeting the N-terminal PWWP (PWWP1) domain of NSD2. UNC6934 occupies the canonical H3K36me2-binding pocket of PWWP1, antagonizes PWWP1 interaction with nucleosomal H3K36me2 and selectively engages endogenous NSD2 in cells. UNC6934 induces accumulation of endogenous NSD2 in the nucleolus, phenocopying the localization defects of NSD2 protein isoforms lacking PWWP1 that result from translocations prevalent in multiple myeloma (MM). Mutations of other NSD2 chromatin reader domains also increase NSD2 nucleolar localization and enhance the effect of UNC6934. This chemical probe and the accompanying negative control UNC7145 will be useful tools in defining NSD2 biology.
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Affiliation(s)
- David Dilworth
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada.
- BlueRock Therapeutics, Toronto, Ontario, Canada.
| | - Ronan P Hanley
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- C4 Therapeutics, Watertown, MA, USA
| | - Renato Ferreira de Freitas
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Arcturus 3, São Bernardo do Campo, Brazil
| | - Abdellah Allali-Hassani
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Incyte, Wilmington, DE, USA
| | - Mengqi Zhou
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Naimee Mehta
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Nurix Therapeutics, San Francisco, CA, USA
| | | | - Suzanne Ackloo
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Dominic D G Owens
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Victoria Vu
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - David Y Nie
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Mona Alqazzaz
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Edyta Marcon
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Fengling Li
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Irene Chau
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Albina Bolotokova
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Su Qin
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Life Science Research Center, Southern University of Science and Technology, Shenzhen, China
| | - Ming Lei
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Yanli Liu
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | | | - Aiping Dong
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Sina Kazemzadeh
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tigran Abramyan
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Atomwise, San Francisco, CA, USA
| | | | | | | | | | - Elisa Gibson
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Dmitri Kireev
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Jinrong Min
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Peter J Brown
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Masoud Vedadi
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Cheryl H Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
- Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Dalia Barsyte-Lovejoy
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
| | - Lindsey I James
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Matthieu Schapira
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
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24
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Verçosa BL, Muniz-Junqueira MI, Batista JF, Socarrás TO, Dias Magalhães LM, Fujiwara RT, Melo MN, Vasconcelos AC. Nucleolar organizer region proteins enhancement in nucleoplasm’s of renal tubular cells is an indication of kidney impairment in Leishmania-infected dogs. Vet Parasitol 2022; 303:109666. [DOI: 10.1016/j.vetpar.2022.109666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 11/25/2022]
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25
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Abstract
Nuclear bodies are membraneless condensates that may form via liquid-liquid phase separation. The viscoelastic chromatin network could impact their stability and may hold the key for understanding experimental observations that defy predictions of classical theories. However, quantitative studies on the role of the chromatin network in phase separation have remained challenging. Using a diploid human genome model parameterized with chromosome conformation capture (Hi-C) data, we study the thermodynamics and kinetics of nucleoli formation. Dynamical simulations predict the formation of multiple droplets for nucleolar particles that experience specific interactions with nucleolus-associated domains (NADs). Coarsening dynamics, surface tension, and coalescence kinetics of the simulated droplets are all in quantitative agreement with experimental measurements for nucleoli. Free energy calculations further support that a two-droplet state, often observed for nucleoli in somatic cells, is metastable and separated from the single-droplet state with an entropic barrier. Our study suggests that nucleoli-chromatin interactions facilitate droplets' nucleation but hinder their coarsening due to the coupled motion between droplets and the chromatin network: as droplets coalesce, the chromatin network becomes increasingly constrained. Therefore, the chromatin network supports a nucleation and arrest mechanism to stabilize the multi-droplet state for nucleoli and possibly for other nuclear bodies.
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26
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Miyake T, McDermott JC. Nucleolar localization of c-Jun. FEBS J 2021; 289:748-765. [PMID: 34499807 DOI: 10.1111/febs.16187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/09/2021] [Accepted: 09/06/2021] [Indexed: 01/20/2023]
Abstract
Nucleoli are well defined for their function in ribosome biogenesis, but only a small fraction of the nucleolar proteome has been characterized. Here, we report that the proto-oncogene, c-Jun, is targeted to the nucleolus. Using live cell imaging in myogenic cells, we document that the c-Jun basic domain contains a unique, evolutionarily conserved motif that determines nucleolar targeting. Fos family Jun dimer partners, such as Fra2, while nuclear, do not co-localize with c-Jun in the nucleolus. A point mutation in c-Jun that mimics Fra2 (M260E) in its Nucleolar Localization sequence (NoLS) results in loss of c-Jun nucleolar targeting while still preserving nuclear localization. Fra2 can sequester c-Jun in the nucleoplasm, indicating that the stoichiometric ratio of heterodimeric partners regulates c-Jun nucleolar targeting. Finally, nucleolar localization of c-Jun modulates nucleolar architecture and ribosomal RNA accumulation. These studies highlight a novel role for Jun family proteins in the nucleolus, having potential implications for a diverse array of AP-1-regulated cellular processes.
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Affiliation(s)
- Tetsuaki Miyake
- Department of Biology, York University, Toronto, ON, Canada.,Muscle Health Research Centre (MHRC), York University, Toronto, ON, Canada.,Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON, Canada
| | - John C McDermott
- Department of Biology, York University, Toronto, ON, Canada.,Muscle Health Research Centre (MHRC), York University, Toronto, ON, Canada.,Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON, Canada.,Centre for Research in Mass Spectrometry (CRMS), York University, Toronto, ON, Canada
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27
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Mobility of Nucleostemin in Live Cells Is Specifically Related to Transcription Inhibition by Actinomycin D and GTP-Binding Motif. Int J Mol Sci 2021; 22:ijms22158293. [PMID: 34361059 PMCID: PMC8347349 DOI: 10.3390/ijms22158293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/24/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
In vertebrates, nucleostemin (NS) is an important marker of proliferation in several types of stem and cancer cells, and it can also interact with the tumor-suppressing transcription factor p53. In the present study, the intra-nuclear diffusional dynamics of native NS tagged with GFP and two GFP-tagged NS mutants with deleted guanosine triphosphate (GTP)-binding domains were analyzed by fluorescence correlation spectroscopy. Free and slow binding diffusion coefficients were evaluated, either under normal culture conditions or under treatment with specific cellular proliferation inhibitors actinomycin D (ActD), 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), or trichostatin A (TSA). When treated with ActD, the fractional ratio of the slow diffusion was significantly decreased in the nucleoplasm. The decrease was proportional to ActD treatment duration. In contrast, DRB or TSA treatment did not affect NS diffusion. Interestingly, it was also found that the rate of diffusion of two NS mutants increased significantly even under normal conditions. These results suggest that the mobility of NS in the nucleoplasm is related to the initiation of DNA or RNA replication, and that the GTP-binding motif is also related to the large change of mobility.
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28
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Holoubek A, Strachotová D, Otevřelová P, Röselová P, Heřman P, Brodská B. AML-Related NPM Mutations Drive p53 Delocalization into the Cytoplasm with Possible Impact on p53-Dependent Stress Response. Cancers (Basel) 2021; 13:cancers13133266. [PMID: 34209894 PMCID: PMC8269334 DOI: 10.3390/cancers13133266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Nucleophosmin (NPM) is one of the most abundant nucleolar proteins and its mutations frequently occur in acute myeloid leukemia (AML). The mutations cause aberrant cytoplasmic localization of mutated protein (NPMmut) and often mediate dislocation of NPM interaction partners. Tumor suppressor p53 is known to interact with NPM in response to genotoxic stress and its cytoplasmic localization is an unfavorable prognostic factor in cancers. This study aims to characterize the NPM-p53 interaction and to elucidate the effect of the NPM mutations on p53 localization and expression in live cells. In addition, the cellular dynamics of NPMmut and p53 after treatment with nuclear export inhibitor Selinexor is described and the mechanism of the Selinexor action proposed. Our results contribute to a better understanding of the oncogenic potential of NPM mutations. Abstract Nucleophosmin (NPM) interaction with tumor suppressor p53 is a part of a complex interaction network and considerably affects cellular stress response. The impact of NPM1 mutations on its interaction with p53 has not been investigated yet, although consequences of NPMmut-induced p53 export to the cytoplasm are important for understanding the oncogenic potential of these mutations. We investigated p53-NPM interaction in live HEK-293T cells by FLIM-FRET and in cell lysates by immunoprecipitation. eGFP lifetime-photoconversion was used to follow redistribution dynamics of NPMmut and p53 in Selinexor-treated cells. We confirmed the p53-NPMwt interaction in intact cells and newly documented that this interaction is not compromised by the NPM mutation causing displacement of p53 to the cytoplasm. Moreover, the interaction was not abolished for non-oligomerizing NPM variants with truncated oligomerization domain, suggesting that oligomerization is not essential for interaction of NPM forms with p53. Inhibition of the nuclear exporter XPO1 by Selinexor caused expected nuclear relocalization of both NPMmut and p53. However, significantly different return rates of these proteins indicate nontrivial mechanism of p53 and NPMmut cellular trafficking. The altered p53 regulation in cells expressing NPMmut offers improved understanding to help investigational strategies targeting these mutations.
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Affiliation(s)
- Aleš Holoubek
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Dita Strachotová
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic;
| | - Petra Otevřelová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Pavla Röselová
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
| | - Petr Heřman
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic;
- Correspondence: (P.H.); (B.B.); Tel.: +420-951-551-461 (P.H.); +420-221-977-354 (B.B.)
| | - Barbora Brodská
- Department of Proteomics, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 20 Prague, Czech Republic; (A.H.); (P.O.); (P.R.)
- Correspondence: (P.H.); (B.B.); Tel.: +420-951-551-461 (P.H.); +420-221-977-354 (B.B.)
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29
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Davis ZH, Mediani L, Antoniani F, Vinet J, Li S, Alberti S, Lu B, Holehouse AS, Carra S, Brandman O. Protein products of nonstop mRNA disrupt nucleolar homeostasis. Cell Stress Chaperones 2021; 26:549-561. [PMID: 33619693 PMCID: PMC8065075 DOI: 10.1007/s12192-021-01200-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/28/2022] Open
Abstract
Stalled mRNA translation results in the production of incompletely synthesized proteins that are targeted for degradation by ribosome-associated quality control (RQC). Here we investigated the fate of defective proteins translated from stall-inducing, nonstop mRNA that escape ubiquitylation by the RQC protein LTN1. We found that nonstop protein products accumulated in nucleoli and this localization was driven by polylysine tracts produced by translation of the poly(A) tails of nonstop mRNA. Nucleolar sequestration increased the solubility of invading proteins but disrupted nucleoli, altering their dynamics, morphology, and resistance to stress in cell culture and intact flies. Our work elucidates how stalled translation may affect distal cellular processes and may inform studies on the pathology of diseases caused by failures in RQC and characterized by nucleolar stress.
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Affiliation(s)
- Zoe H Davis
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA
| | - Laura Mediani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio, Emilia, Modena, Italy
| | - Francesco Antoniani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio, Emilia, Modena, Italy
| | - Jonathan Vinet
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio, Emilia, Modena, Italy
| | - Shuangxi Li
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitat Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Bingwei Lu
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Serena Carra
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio, Emilia, Modena, Italy.
| | - Onn Brandman
- Department of Biochemistry, Stanford University, Stanford, CA, 94305, USA.
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30
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Mukherjee T, Soppina V, Ludovic R, Mély Y, Klymchenko AS, Collot M, Kanvah S. Live-cell imaging of the nucleolus and mapping mitochondrial viscosity with a dual function fluorescent probe. Org Biomol Chem 2021; 19:3389-3395. [PMID: 33555275 DOI: 10.1039/d0ob02378g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Visualization of sub-cellular organelles allows the determination of various cellular processes and the underlying mechanisms. Herein, we report a fluorescent probe, bearing push-pull substituents emitting at 600 nm and its application in cellular imaging. The probe shows dual imaging of mitochondria and nucleoli and maps mitochondrial viscosity in live cells under various physiological variations and show minimum cytotoxicity. Nucleolar staining is confirmed by RNAase digestion.
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Affiliation(s)
- Tarushyam Mukherjee
- Discipline of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar 382355, India.
| | - Virupakshi Soppina
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar 382355, India.
| | - Richert Ludovic
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS/Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Graffenstaden, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS/Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Graffenstaden, France
| | - Andrey S Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS/Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Graffenstaden, France
| | - Mayeul Collot
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS/Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Graffenstaden, France
| | - Sriram Kanvah
- Discipline of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar 382355, India.
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31
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Itoh Y, Iida S, Tamura S, Nagashima R, Shiraki K, Goto T, Hibino K, Ide S, Maeshima K. 1,6-hexanediol rapidly immobilizes and condenses chromatin in living human cells. Life Sci Alliance 2021; 4:e202001005. [PMID: 33536240 PMCID: PMC7898662 DOI: 10.26508/lsa.202001005] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 01/19/2021] [Indexed: 12/15/2022] Open
Abstract
Liquid droplets formed inside the cell by liquid-liquid phase separation maintain membrane-less condensates/bodies (or compartments). These droplets are important for concentrating certain molecules and facilitating spatiotemporal regulation of cellular functions. 1,6-hexanediol (1,6-HD), an aliphatic alcohol, inhibits weak hydrophobic protein-protein/protein-RNA interactions required for the droplet formation (droplet melting activity) and is used here to elucidate the formation process of cytoplasmic/nuclear condensates/bodies. However, the effect of 1,6-HD on chromatin in living cells remains unclear. We found that 1,6-HD drastically suppresses chromatin motion and hyper-condenses chromatin in human cells by using live-cell single-nucleosome imaging, which detects changes in the state of chromatin. These effects were enhanced in a dose-dependent manner. Chromatin was "frozen" by 5%, or higher, concentrations of 1,6-HD. 1,6-HD greatly facilitated cation-dependent chromatin condensation in vitro. This 1,6-HD action is distinct from its melting activity of liquid droplets. Alcohols, such as 1,6-HD, appear to remove water molecules around chromatin and locally condense chromatin. Therefore, liquid droplet results obtained using 1,6-HD should be carefully interpreted or reconsidered when these droplets are associated with chromatin.
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Affiliation(s)
- Yuji Itoh
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
| | - Ryosuke Nagashima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
| | - Kentaro Shiraki
- Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tatsuhiko Goto
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
- Department of Life and Food Sciences, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Kayo Hibino
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
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32
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Shi S, Luo H, Wang L, Li H, Liang Y, Xia J, Wang Z, Cheng B, Huang L, Liao G, Xu B. Combined inhibition of RNA polymerase I and mTORC1/2 synergize to combat oral squamous cell carcinoma. Biomed Pharmacother 2021; 133:110906. [PMID: 33190037 DOI: 10.1016/j.biopha.2020.110906] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 10/13/2020] [Accepted: 10/16/2020] [Indexed: 01/27/2023] Open
Abstract
Oral squamous cell carcinoma (OSCC) is the major cause of morbidity and mortality in head and neck cancer patients worldwide. This malignant disease is challenging to treat because of the lack of effective curative strategies and the high incidence of recurrence. This study aimed to investigate the efficacy of a single and dual approach targeting ribosome biogenesis and protein translation to treat OSCC associated with the copy number variation (CNV) of ribosomal DNA (rDNA). Here, we found that primary OSCC tumors frequently exhibited a partial loss of 45S rDNA copy number and demonstrated a high susceptibility to CX5461 (a selective inhibitor of RNA polymerase I) and the coadministration of CX5461 and INK128 (a potent inhibitor of mTORC1/2). Combined treatment displayed the promising synergistic effects that induced cell apoptosis and reactive oxygen species (ROS) generation, and inhibited cell growth and proliferation. Moreover, INK128 compromised NHEJ-DNA repair pathway to reinforce the antitumor activity of CX5461. In vivo, the cotreatment synergistically suppressed tumor growth, triggered apoptosis and strikingly extended the survival time of tumor-bearing mice. Additionally, treatment with the individual compounds and coadministration appeared to reduce the incidence of enlarged inguinal lymph nodes. Our study supports that the combination of CX5461 and INK128 is a novel and efficacious therapeutic strategy that can combat this cancer and that 45S rDNA may serve as a useful indicator to predict the efficacy of this cotreatment.
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Affiliation(s)
- Shanwei Shi
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Huigen Luo
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Lihong Wang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Hua Li
- The Stowers Institute for Medical Research, Kansas City, Missouri, United States
| | - Yujie Liang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Juan Xia
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Zhi Wang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Bin Cheng
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Linfeng Huang
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Guiqing Liao
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China.
| | - Baoshan Xu
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong Province, China.
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33
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Ardehali MB, Damle M, Perea-Resa C, Blower MD, Kingston RE. Elongin A associates with actively transcribed genes and modulates enhancer RNA levels with limited impact on transcription elongation rate in vivo. J Biol Chem 2020; 296:100202. [PMID: 33334895 PMCID: PMC7948453 DOI: 10.1074/jbc.ra120.015877] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/06/2020] [Accepted: 12/16/2020] [Indexed: 01/08/2023] Open
Abstract
Elongin A (EloA) is an essential transcription factor that stimulates the rate of RNA polymerase II (Pol II) transcription elongation in vitro. However, its role as a transcription factor in vivo has remained underexplored. Here we show that in mouse embryonic stem cells, EloA localizes to both thousands of Pol II transcribed genes with preference for transcription start site and promoter regions and a large number of active enhancers across the genome. EloA deletion results in accumulation of transcripts from a subset of enhancers and their adjacent genes. Notably, EloA does not substantially enhance the elongation rate of Pol II in vivo. We also show that EloA localizes to the nucleoli and associates with RNA polymerase I transcribed ribosomal RNA gene, Rn45s. EloA is a highly disordered protein, which we demonstrate forms phase-separated condensates in vitro, and truncation mutations in the intrinsically disordered regions (IDR) of EloA interfere with its targeting and localization to the nucleoli. We conclude that EloA broadly associates with transcribed regions, tunes RNA Pol II transcription levels via impacts on enhancer RNA synthesis, and interacts with the rRNA producing/processing machinery in the nucleolus. Our work opens new avenues for further investigation of the role of this functionally multifaceted transcription factor in enhancer and ribosomal RNA biology.
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Affiliation(s)
- M Behfar Ardehali
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Manashree Damle
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Carlos Perea-Resa
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael D Blower
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
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34
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Ding T, Zhu L, Fang Y, Liu Y, Tang W, Zou P. Chromophore‐Assisted Proximity Labeling of DNA Reveals Chromosomal Organization in Living Cells. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tao Ding
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Liyuan Zhu
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Yuxin Fang
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Yangluorong Liu
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Wei Tang
- Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China
- Peking-Tsinghua Center for Life Sciences Beijing 100871 China
| | - Peng Zou
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
- Peking-Tsinghua Center for Life Sciences Beijing 100871 China
- PKU-IDG/McGovern Institute for Brain Research Beijing 100871 China
- Chinese Institute for Brain Research (CIBR) Beijing 102206 China
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35
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Muthunayake NS, Tomares DT, Childers WS, Schrader JM. Phase-separated bacterial ribonucleoprotein bodies organize mRNA decay. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1599. [PMID: 32445438 PMCID: PMC7554086 DOI: 10.1002/wrna.1599] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 01/12/2023]
Abstract
In bacteria, mRNA decay is controlled by megadalton scale macromolecular assemblies called, "RNA degradosomes," composed of nucleases and other RNA decay associated proteins. Recent advances in bacterial cell biology have shown that RNA degradosomes can assemble into phase-separated structures, termed bacterial ribonucleoprotein bodies (BR-bodies), with many analogous properties to eukaryotic processing bodies and stress granules. This review will highlight the functional role that BR-bodies play in the mRNA decay process through its organization into a membraneless organelle in the bacterial cytoplasm. This review will also highlight the phylogenetic distribution of BR-bodies across bacterial species, which suggests that these phase-separated structures are broadly distributed across bacteria, and in evolutionarily related mitochondria and chloroplasts. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
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36
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Ding T, Zhu L, Fang Y, Liu Y, Tang W, Zou P. Chromophore‐Assisted Proximity Labeling of DNA Reveals Chromosomal Organization in Living Cells. Angew Chem Int Ed Engl 2020; 59:22933-22937. [DOI: 10.1002/anie.202005486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/11/2020] [Indexed: 01/26/2023]
Affiliation(s)
- Tao Ding
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Liyuan Zhu
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Yuxin Fang
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Yangluorong Liu
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
| | - Wei Tang
- Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China
- Peking-Tsinghua Center for Life Sciences Beijing 100871 China
| | - Peng Zou
- College of Chemistry and Molecular Engineering Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China
- Peking-Tsinghua Center for Life Sciences Beijing 100871 China
- PKU-IDG/McGovern Institute for Brain Research Beijing 100871 China
- Chinese Institute for Brain Research (CIBR) Beijing 102206 China
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37
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Ide S, Imai R, Ochi H, Maeshima K. Transcriptional suppression of ribosomal DNA with phase separation. SCIENCE ADVANCES 2020; 6:6/42/eabb5953. [PMID: 33055158 PMCID: PMC7556839 DOI: 10.1126/sciadv.abb5953] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/25/2020] [Indexed: 05/21/2023]
Abstract
The nucleolus is a nuclear body with multiphase liquid droplets for ribosomal RNA (rRNA) transcription. How rRNA transcription is regulated in the droplets remains unclear. Here, using single-molecule tracking of RNA polymerase I (Pol I) and chromatin-bound upstream binding factor (UBF), we reveal suppression of transcription with phase separation. For transcription, active Pol I formed small clusters/condensates that constrained rDNA chromatin in the nucleolus fibrillar center (FC). Treatment with a transcription inhibitor induced Pol I to dissociate from rDNA chromatin and to move like a liquid within the nucleolar cap that transformed from the FC. Expression of a Pol I mutant associated with a craniofacial disorder inhibited transcription by competing with wild-type Pol I clusters and transforming the FC into the nucleolar cap. The cap droplet excluded an initiation factor, ensuring robust silencing. Our findings suggest a mechanism of rRNA transcription suppression via phase separation of intranucleolar molecules governed by Pol I.
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Affiliation(s)
- Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), Shizuoka 411-8540, Japan
| | - Ryosuke Imai
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), Shizuoka 411-8540, Japan
| | - Hiroko Ochi
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), Shizuoka 411-8540, Japan
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38
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Esgleas M, Falk S, Forné I, Thiry M, Najas S, Zhang S, Mas-Sanchez A, Geerlof A, Niessing D, Wang Z, Imhof A, Götz M. Trnp1 organizes diverse nuclear membrane-less compartments in neural stem cells. EMBO J 2020; 39:e103373. [PMID: 32627867 PMCID: PMC7429739 DOI: 10.15252/embj.2019103373] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 11/09/2022] Open
Abstract
TMF1‐regulated nuclear protein 1 (Trnp1) has been shown to exert potent roles in neural development affecting neural stem cell self‐renewal and brain folding, but its molecular function in the nucleus is still unknown. Here, we show that Trnp1 is a low complexity protein with the capacity to phase separate. Trnp1 interacts with factors located in several nuclear membrane‐less organelles, the nucleolus, nuclear speckles, and condensed chromatin. Importantly, Trnp1 co‐regulates the architecture and function of these nuclear compartments in vitro and in the developing brain in vivo. Deletion of a highly conserved region in the N‐terminal intrinsic disordered region abolishes the capacity of Trnp1 to regulate nucleoli and heterochromatin size, proliferation, and M‐phase length; decreases the capacity to phase separate; and abrogates most of Trnp1 protein interactions. Thus, we identified Trnp1 as a novel regulator of several nuclear membrane‐less compartments, a function important to maintain cells in a self‐renewing proliferative state.
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Affiliation(s)
- Miriam Esgleas
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, Planegg/Munich, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - Sven Falk
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, Planegg/Munich, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - Ignasi Forné
- Protein Analysis Unit, BioMedical Center (BMC), Ludwig-Maximilians-Universitaet Muenchen, Planegg/Munich, Germany
| | - Marc Thiry
- Cell and Tissue Biology Unit, GIGA-Neurosciences, University of Liege, C.H.U. Sart Tilman, Liege, Belgium
| | - Sonia Najas
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, Planegg/Munich, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - Sirui Zhang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Aina Mas-Sanchez
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, Planegg/Munich, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Helmholtz Zentrum Muenchen, Neuherberg, Germany
| | - Dierk Niessing
- Group Intracellular Transport and RNA Biology at the Institute of Structural Biology, Helmholtz Zentrum Muenchen, Neuherberg, Germany.,Department of Cell Biology, BioMedical Center (BMC), Ludwig-Maximilians-Universitaet Muenchen, Planegg/Munich, Germany
| | - Zefeng Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Axel Imhof
- Protein Analysis Unit, BioMedical Center (BMC), Ludwig-Maximilians-Universitaet Muenchen, Planegg/Munich, Germany.,SYNERGY, Excellence Cluster of Systems Neurology, BioMedical Center (BMC), Ludwig-Maximilians-Universitaet Muenchen, Planegg/Munich, Germany
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center (BMC), Ludwig-Maximilians Universitaet Muenchen, Planegg/Munich, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg, Germany.,SYNERGY, Excellence Cluster of Systems Neurology, BioMedical Center (BMC), Ludwig-Maximilians-Universitaet Muenchen, Planegg/Munich, Germany
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39
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Pang MYH, Sun X, Ausió J, Ishibashi T. Histone H4 variant, H4G, drives ribosomal RNA transcription and breast cancer cell proliferation by loosening nucleolar chromatin structure. J Cell Physiol 2020; 235:9601-9608. [PMID: 32385931 DOI: 10.1002/jcp.29770] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/09/2020] [Accepted: 04/25/2020] [Indexed: 02/06/2023]
Abstract
The hominidae-specific histone variant H4G is expressed in breast cancer patients in a stage-dependent manner. H4G localizes primarily in the nucleoli via its interaction with nucleophosmin (NPM1). H4G is involved in rDNA transcription and ribosome biogenesis, which facilitates breast cancer cell proliferation. However, the molecular mechanism underlying this process remains unknown. Here, we show that H4G is not stably incorporated into nucleolar chromatin, even with the chaperoning assistance of NPM1. H4G likely form transient nucleosome-like-structure that undergoes rapid dissociation. In addition, the nucleolar chromatin in H4GKO cells is more compact than WT cells. Altogether, our results suggest that H4G relaxes the nucleolar chromatin and enhances rRNA transcription by forming destabilized nucleosome in breast cancer cells.
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Affiliation(s)
- Matthew Y H Pang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Xulun Sun
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Toyotaka Ishibashi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
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40
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Guillen-Chable F, Rodríguez Corona U, Pereira-Santana A, Bayona A, Rodríguez-Zapata LC, Aquino C, Šebestová L, Vitale N, Hozak P, Castano E. Fibrillarin Ribonuclease Activity is Dependent on the GAR Domain and Modulated by Phospholipids. Cells 2020; 9:cells9051143. [PMID: 32384686 PMCID: PMC7290794 DOI: 10.3390/cells9051143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/24/2020] [Accepted: 04/29/2020] [Indexed: 12/16/2022] Open
Abstract
Fibrillarin is a highly conserved nucleolar methyltransferase responsible for ribosomal RNA methylation across evolution from Archaea to humans. It has been reported that fibrillarin is involved in the methylation of histone H2A in nucleoli and other processes, including viral progression, cellular stress, nuclear shape, and cell cycle progression. We show that fibrillarin has an additional activity as a ribonuclease. The activity is affected by phosphoinositides and phosphatidic acid and insensitive to ribonuclease inhibitors. Furthermore, the presence of phosphatidic acid releases the fibrillarin-U3 snoRNA complex. We show that the ribonuclease activity localizes to the GAR (glycine/arginine-rich) domain conserved in a small group of RNA interacting proteins. The introduction of the GAR domain occurred in evolution in the transition from archaea to eukaryotic cells. The interaction of this domain with phospholipids may allow a phase separation of this protein in nucleoli.
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Affiliation(s)
- Francisco Guillen-Chable
- Biochemistry and Molecular Plant Biology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatán, Mexico; (F.G.-C.); (U.R.C.); (A.B.); (C.A.)
| | - Ulises Rodríguez Corona
- Biochemistry and Molecular Plant Biology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatán, Mexico; (F.G.-C.); (U.R.C.); (A.B.); (C.A.)
| | - Alejandro Pereira-Santana
- Industrial Biotechnology Department, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Camino Arenero 1227, el Bajio, Zapopan C.P. 45019, Jalisco, Mexico;
- Dirección de Cátedras, Consejo Nacional de Ciencia y Tecnología, Av. Insurgentes Sur 1582, Alcaldia Benito Juarez C.P. 03940, Ciudad de Mexico, Mexico
| | - Andrea Bayona
- Biochemistry and Molecular Plant Biology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatán, Mexico; (F.G.-C.); (U.R.C.); (A.B.); (C.A.)
| | - Luis Carlos Rodríguez-Zapata
- Biotechnology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatan, Mexico;
| | - Cecilia Aquino
- Biochemistry and Molecular Plant Biology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatán, Mexico; (F.G.-C.); (U.R.C.); (A.B.); (C.A.)
| | - Lenka Šebestová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the CAS, v.v.i., Videnska 1083, 142 20 Prague, Czech Republic; (L.Š.); (P.H.)
- Faculty of Science, Charles University, Albertov 6, 128 00 Prague, Czech Republic
| | - Nicolas Vitale
- Institute of Celullar and Integrative Neuroscience (INCI), UPR-3212 The French National Centre for Scientific Research & University of Strasbourg, 67000 Strasbourg, France;
| | - Pavel Hozak
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the CAS, v.v.i., Videnska 1083, 142 20 Prague, Czech Republic; (L.Š.); (P.H.)
| | - Enrique Castano
- Biochemistry and Molecular Plant Biology Department, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida C.P. 97200, Yucatán, Mexico; (F.G.-C.); (U.R.C.); (A.B.); (C.A.)
- Correspondence:
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41
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Muscolino E, Schmitz R, Loroch S, Caragliano E, Schneider C, Rizzato M, Kim YH, Krause E, Juranić Lisnić V, Sickmann A, Reimer R, Ostermann E, Brune W. Herpesviruses induce aggregation and selective autophagy of host signalling proteins NEMO and RIPK1 as an immune-evasion mechanism. Nat Microbiol 2019; 5:331-342. [DOI: 10.1038/s41564-019-0624-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 10/30/2019] [Indexed: 12/13/2022]
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42
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Kour R, Komar AA, Mazumder B. Mutually exclusive amino acid residues of L13a are responsible for its ribosomal incorporation and translational silencing leading to resolution of inflammation. RNA (NEW YORK, N.Y.) 2019; 25:1377-1392. [PMID: 31308261 PMCID: PMC6800476 DOI: 10.1261/rna.071118.119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/11/2019] [Indexed: 05/09/2023]
Abstract
Eukaryotic ribosomal protein L13a is a member of the conserved universal ribosomal uL13 protein family. Structurally, L13a is distinguished from its prokaryotic counterparts by the presence of an ∼55 amino acid-long carboxy-terminal α-helical extension. The importance of these evolved residues in the carboxy-terminal extension for mammalian ribosome biogenesis as well as L13a's extraribosomal function in GAIT (γ interferon-activated inhibitor of translation) complex-mediated translation silencing during inflammation is not understood. Here, we present biochemical analyses of L13a mutant variants identifying several mutually exclusive amino acid residues in the eukaryote-specific carboxy-terminal extension of human L13a (Tyr149-Val203) important for ribosomal incorporation and translational silencing. Specifically, we show that mutation of Arg169, Lys170, and Lys171 to Ala abrogate GAIT-mediated translational silencing, but not L13a incorporation into ribosomes. Moreover, we show that the carboxy-terminal helix alone can silence translation of GAIT element-containing mRNAs in vitro. We also show through cellular immunofluorescence experiments that nuclear but not nucleolar localization of L13a is resistant to extensive amino acid alterations, suggesting that multiple complex nuclear import signals are present within this protein. These studies provide new insights into L13a structure and its ribosomal and extraribosomal functions in model human cells.
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Affiliation(s)
- Ravinder Kour
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
| | - Barsanjit Mazumder
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
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43
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Cerqueira AV, Lemos B. Ribosomal DNA and the Nucleolus as Keystones of Nuclear Architecture, Organization, and Function. Trends Genet 2019; 35:710-723. [PMID: 31447250 DOI: 10.1016/j.tig.2019.07.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 12/12/2022]
Abstract
The multicopy ribosomal DNA (rDNA) array gives origin to the nucleolus, a large nonmembrane-bound organelle that occupies a substantial volume within the cell nucleus. The rDNA/nucleolus has emerged as a coordinating hub in which seemingly disparate cellular functions converge, and from which a variety of cellular and organismal phenotypes emerge. However, the role of the nucleolus as a determinant and organizer of nuclear architecture and other epigenetic states of the genome is not well understood. We discuss the role of rDNA and the nucleolus in nuclear organization and function - from nucleolus-associated domains (NADs) to the regulation of imprinted loci and X chromosome inactivation, as well as rDNA contact maps that anchor and position the rDNA relative to the rest of the genome. The influence of the nucleolus on nuclear organization undoubtedly modulates diverse biological processes from metabolism to cell proliferation, genome-wide gene expression, maintenance of epigenetic states, and aging.
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Affiliation(s)
- Amanda V Cerqueira
- Department of Environmental Health, Program in Molecular and Integrative Physiological Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Bernardo Lemos
- Department of Environmental Health, Program in Molecular and Integrative Physiological Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
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44
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Kim TK, Lee BW, Fujii F, Kim JK, Pack CG. Physicochemical Properties of Nucleoli in Live Cells Analyzed by Label-Free Optical Diffraction Tomography. Cells 2019; 8:cells8070699. [PMID: 31295945 PMCID: PMC6679011 DOI: 10.3390/cells8070699] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/27/2019] [Accepted: 07/09/2019] [Indexed: 12/15/2022] Open
Abstract
The cell nucleus is three-dimensionally and dynamically organized by nuclear components with high molecular density, such as chromatin and nuclear bodies. The structure and functions of these components are represented by the diffusion and interaction of related factors. Recent studies suggest that the nucleolus can be assessed using various protein probes, as the probes are highly mobile in this organelle, although it is known that they have a densely packed structure. However, physicochemical properties of the nucleolus itself, such as molecular density and volume when cellular conditions are changed, are not yet fully understood. In this study, physical parameters such as the refractive index (RI) and volume of the nucleoli in addition to the diffusion coefficient (D) of fluorescent probe protein inside the nucleolus are quantified and compared by combining label-free optical diffraction tomography (ODT) with confocal laser scanning microscopy (CLSM)-based fluorescence correlation spectroscopy (FCS). 3D evaluation of RI values and corresponding RI images of nucleoli in live HeLa cells successfully demonstrated varying various physiological conditions. Our complimentary method suggests that physical property of the nucleolus in live cell is sensitive to ATP depletion and transcriptional inhibition, while it is insensitive to hyper osmotic pressure when compared with the cytoplasm and nucleoplasm. The result demonstrates that the nucleolus has unique physicochemical properties when compared with other cellular components.
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Affiliation(s)
- Tae-Keun Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Byong-Wook Lee
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Fumihiko Fujii
- Division of Physical Pharmacy, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan
| | - Jun Ki Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea.
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea.
| | - Chan-Gi Pack
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea.
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea.
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45
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Potapova TA, Unruh JR, Yu Z, Rancati G, Li H, Stampfer MR, Gerton JL. Superresolution microscopy reveals linkages between ribosomal DNA on heterologous chromosomes. J Cell Biol 2019; 218:2492-2513. [PMID: 31270138 PMCID: PMC6683752 DOI: 10.1083/jcb.201810166] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/14/2019] [Accepted: 06/03/2019] [Indexed: 12/15/2022] Open
Abstract
Potapova et al. use superresolution microscopy to describe linkages between ribosomal DNA on heterologous human chromosomes whose formation depends on the transcription factor UBF and topoisomerase II. Linkages persist in the absence of cohesion but require topoisomerase II for resolution. The spatial organization of the genome is enigmatic. Direct evidence of physical contacts between chromosomes and their visualization at nanoscale resolution has been limited. We used superresolution microscopy to demonstrate that ribosomal DNA (rDNA) can form linkages between chromosomes. We observed rDNA linkages in many different human cell types and demonstrated their resolution in anaphase. rDNA linkages are coated by the transcription factor UBF and their formation depends on UBF, indicating that they regularly occur between transcriptionally active loci. Overexpression of c-Myc increases rDNA transcription and the frequency of rDNA linkages, further suggesting that their formation depends on active transcription. Linkages persist in the absence of cohesion, but inhibition of topoisomerase II prevents their resolution in anaphase. We propose that linkages are topological intertwines occurring between transcriptionally active rDNA loci spatially colocated in the same nucleolar compartment. Our findings suggest that active DNA loci engage in physical interchromosomal connections that are an integral and pervasive feature of genome organization.
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Affiliation(s)
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO
| | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, MO
| | - Giulia Rancati
- Institute of Medical Biology, Agency for Science, Technology and Research, Singapore
| | - Hua Li
- Stowers Institute for Medical Research, Kansas City, MO
| | - Martha R Stampfer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Jennifer L Gerton
- Stowers Institute for Medical Research, Kansas City, MO .,Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS
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46
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Chen Y, Li J, Cao F, Lam J, Cheng CC, Yu CH, Huen MS. Nucleolar residence of the seckel syndrome protein TRAIP is coupled to ribosomal DNA transcription. Nucleic Acids Res 2019; 46:10119-10131. [PMID: 30165463 PMCID: PMC6212796 DOI: 10.1093/nar/gky775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 08/16/2018] [Indexed: 12/30/2022] Open
Abstract
The RING finger protein TRAIP protects genome integrity and its mutation causes Seckel syndrome. TRAIP encodes a nucleolar protein that migrates to UV-induced DNA lesions via a direct interaction with the DNA replication clamp PCNA. Thus far, mechanistically how UV mobilizes TRAIP from the nucleoli remains unknown. We found that PCNA binding is dispensable for the nucleolus-nucleoplasm shuttling of TRAIP following cell exposure to UV irradiation, and that its redistribution did not rely on the master DNA damage kinases ATM and ATR. Interestingly, I-PpoI-induced ribosomal DNA damage led to TRAIP exclusion from the nucleoli, raising the possibility that active ribosomal DNA transcription may underlie TRAIP retention in the nuclear sub-compartments. Accordingly, chemical inhibition of RNA polymerase I activity led to TRAIP diffusion into the nucleoplasm, and was coupled with marked reduction of DNA/RNA hybrids in the nucleoli, suggesting that TRAIP may be sequestered via binding to nucleic acid structures in the nucleoli. Consistently, cell pre-treatment with DNase/RNase effectively released TRAIP from the nucleoli. Taken together, our study defines a bipartite mechanism that drives TRAIP trafficking in response to UV damage, and highlights the nucleolus as a stress sensor that contributes to orchestrating DNA damage responses.
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Affiliation(s)
- Yangzi Chen
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Junshi Li
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Fakun Cao
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Jason Lam
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Clooney Cy Cheng
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Cheng-Han Yu
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Michael Sy Huen
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R.,Center for Synthetic Biology Engineering Research, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong S.A.R
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47
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Iarovaia OV, Minina EP, Sheval EV, Onichtchouk D, Dokudovskaya S, Razin SV, Vassetzky YS. Nucleolus: A Central Hub for Nuclear Functions. Trends Cell Biol 2019; 29:647-659. [PMID: 31176528 DOI: 10.1016/j.tcb.2019.04.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022]
Abstract
The nucleolus is the largest and most studied nuclear body, but its role in nuclear function is far from being comprehensively understood. Much work on the nucleolus has focused on its role in regulating RNA polymerase I (RNA Pol I) transcription and ribosome biogenesis; however, emerging evidence points to the nucleolus as an organizing hub for many nuclear functions, accomplished via the shuttling of proteins and nucleic acids between the nucleolus and nucleoplasm. Here, we discuss the cellular mechanisms affected by shuttling of nucleolar components, including the 3D organization of the genome, stress response, DNA repair and recombination, transcription regulation, telomere maintenance, and other essential cellular functions.
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Affiliation(s)
- Olga V Iarovaia
- Institute of Gene Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France
| | - Elizaveta P Minina
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Eugene V Sheval
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Daria Onichtchouk
- Developmental Biology Unit, Department of Biology I, University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany
| | - Svetlana Dokudovskaya
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; UMR8126, Université Paris-Sud, CNRS, Institut Gustave Roussy, 94805 Villejuif, France
| | - Sergey V Razin
- Institute of Gene Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Yegor S Vassetzky
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; UMR8126, Université Paris-Sud, CNRS, Institut Gustave Roussy, 94805 Villejuif, France.
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48
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McSwiggen DT, Hansen AS, Teves SS, Marie-Nelly H, Hao Y, Heckert AB, Umemoto KK, Dugast-Darzacq C, Tjian R, Darzacq X. Evidence for DNA-mediated nuclear compartmentalization distinct from phase separation. eLife 2019; 8:e47098. [PMID: 31038454 PMCID: PMC6522219 DOI: 10.7554/elife.47098] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022] Open
Abstract
RNA Polymerase II (Pol II) and transcription factors form concentrated hubs in cells via multivalent protein-protein interactions, often mediated by proteins with intrinsically disordered regions. During Herpes Simplex Virus infection, viral replication compartments (RCs) efficiently enrich host Pol II into membraneless domains, reminiscent of liquid-liquid phase separation. Despite sharing several properties with phase-separated condensates, we show that RCs operate via a distinct mechanism wherein unrestricted nonspecific protein-DNA interactions efficiently outcompete host chromatin, profoundly influencing the way DNA-binding proteins explore RCs. We find that the viral genome remains largely nucleosome-free, and this increase in accessibility allows Pol II and other DNA-binding proteins to repeatedly visit nearby DNA binding sites. This anisotropic behavior creates local accumulations of protein factors despite their unrestricted diffusion across RC boundaries. Our results reveal underappreciated consequences of nonspecific DNA binding in shaping gene activity, and suggest additional roles for chromatin in modulating nuclear function and organization.
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Affiliation(s)
- David Trombley McSwiggen
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- California Institute of Regenerative Medicine Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Anders S Hansen
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- California Institute of Regenerative Medicine Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Sheila S Teves
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Department of Biochemistry and Molecular BiologyUniversity of British ColumbiaVancouverCanada
| | - Hervé Marie-Nelly
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- California Institute of Regenerative Medicine Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Yvonne Hao
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Alec Basil Heckert
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- California Institute of Regenerative Medicine Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Kayla K Umemoto
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Claire Dugast-Darzacq
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- California Institute of Regenerative Medicine Center of ExcellenceUniversity of California, BerkeleyBerkeleyUnited States
| | - Robert Tjian
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
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49
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Kösling SK, Fansa EK, Maffini S, Wittinghofer A. Mechanism and dynamics of INPP5E transport into and inside the ciliary compartment. Biol Chem 2018; 399:277-292. [PMID: 29140789 DOI: 10.1515/hsz-2017-0226] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/03/2017] [Indexed: 11/15/2022]
Abstract
The inositol polyphosphate 5'-phosphatase E (INPP5E) localizes to cilia. We showed that the carrier protein phosphodiesterase 6 delta subunit (PDE6δ) mediates the sorting of farnesylated INPP5E into cilia due to high affinity binding and release by the ADP-ribosylation factor (Arf)-like protein Arl3·GTP. However, the dynamics of INPP5E transport into and inside the ciliary compartment are not fully understood. Here, we investigate the movement of INPP5E using live cell fluorescence microscopy and fluorescence recovery after photobleaching (FRAP) analysis. We show that PDE6δ and the dynein transport system are essential for ciliary sorting and entry of INPP5E. However, its innerciliary transport is regulated solely by the intraflagellar transport (IFT) system, independent from PDE6δ activity and INPP5E farnesylation. By contrast, movement of Arl3 into and within cilia occurs freely by diffusion and IFT-independently. The farnesylation defective INPP5E CaaX box mutant loses the exclusive ciliary localization. The accumulation of this mutant at centrioles after photobleaching suggests an affinity trap mechanism for ciliary entry, that in case of the wild type is overcome by the interaction with PDE6δ. Collectively, we postulate a three-step mechanism regulating ciliary localization of INPP5E, consisting of farnesylation- and PDE6δ-mediated targeting, INPP5E-PDE6δ complex diffusion into the cilium with transfer to the IFT system, and retention inside cilia.
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Affiliation(s)
- Stefanie Kristine Kösling
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Eyad Kalawy Fansa
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
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50
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Mitrea DM, Chandra B, Ferrolino MC, Gibbs EB, Tolbert M, White MR, Kriwacki RW. Methods for Physical Characterization of Phase-Separated Bodies and Membrane-less Organelles. J Mol Biol 2018; 430:4773-4805. [PMID: 30017918 PMCID: PMC6503534 DOI: 10.1016/j.jmb.2018.07.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/17/2022]
Abstract
Membrane-less organelles are cellular structures which arise through the phenomenon of phase separation. This process enables compartmentalization of specific sets of macromolecules (e.g., proteins, nucleic acids), thereby regulating cellular processes by increasing local concentration, and modulating the structure and dynamics of their constituents. Understanding the connection between structure, material properties and function of membrane-less organelles requires inter-disciplinary approaches, which address length and timescales that span several orders of magnitude (e.g., Ångstroms to micrometer, picoseconds to hours). In this review, we discuss the wide variety of methods that have been applied to characterize the morphology, rheology, structure and dynamics of membrane-less organelles and their components, in vitro and in live cells.
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Affiliation(s)
- Diana M Mitrea
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Bappaditya Chandra
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Mylene C Ferrolino
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Eric B Gibbs
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michele Tolbert
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michael R White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA.
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