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Ling YH, Ye Z, Liang C, Yu C, Park G, Corden JL, Wu C. Disordered C-terminal domain drives spatiotemporal confinement of RNAPII to enhance search for chromatin targets. Nat Cell Biol 2024; 26:581-592. [PMID: 38548891 DOI: 10.1038/s41556-024-01382-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 02/21/2024] [Indexed: 04/09/2024]
Abstract
Efficient gene expression requires RNA polymerase II (RNAPII) to find chromatin targets precisely in space and time. How RNAPII manages this complex diffusive search in three-dimensional nuclear space remains largely unknown. The disordered carboxy-terminal domain (CTD) of RNAPII, which is essential for recruiting transcription-associated proteins, forms phase-separated droplets in vitro, hinting at a potential role in modulating RNAPII dynamics. In the present study, we use single-molecule tracking and spatiotemporal mapping in living yeast to show that the CTD is required for confining RNAPII diffusion within a subnuclear region enriched for active genes, but without apparent phase separation into condensates. Both Mediator and global chromatin organization are required for sustaining RNAPII confinement. Remarkably, truncating the CTD disrupts RNAPII spatial confinement, prolongs target search, diminishes chromatin binding, impairs pre-initiation complex formation and reduces transcription bursting. The present study illuminates the pivotal role of the CTD in driving spatiotemporal confinement of RNAPII for efficient gene expression.
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Affiliation(s)
- Yick Hin Ling
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Ziyang Ye
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Chloe Liang
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Chuofan Yu
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Giho Park
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffry L Corden
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Ling YH, Ye Z, Liang C, Yu C, Park G, Corden JL, Wu C. Disordered C-terminal domain drives spatiotemporal confinement of RNAPII to enhance search for chromatin targets. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551302. [PMID: 37577667 PMCID: PMC10418089 DOI: 10.1101/2023.07.31.551302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Efficient gene expression requires RNA Polymerase II (RNAPII) to find chromatin targets precisely in space and time. How RNAPII manages this complex diffusive search in 3D nuclear space remains largely unknown. The disordered carboxy-terminal domain (CTD) of RNAPII, which is essential for recruiting transcription-associated proteins, forms phase-separated droplets in vitro, hinting at a potential role in modulating RNAPII dynamics. Here, we use single-molecule tracking and spatiotemporal mapping in living yeast to show that the CTD is required for confining RNAPII diffusion within a subnuclear region enriched for active genes, but without apparent phase separation into condensates. Both Mediator and global chromatin organization are required for sustaining RNAPII confinement. Remarkably, truncating the CTD disrupts RNAPII spatial confinement, prolongs target search, diminishes chromatin binding, impairs pre-initiation complex formation, and reduces transcription bursting. This study illuminates the pivotal role of the CTD in driving spatiotemporal confinement of RNAPII for efficient gene expression.
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Affiliation(s)
- Yick Hin Ling
- Department of Biology, Johns Hopkins University, Baltimore, USA
| | - Ziyang Ye
- Department of Biology, Johns Hopkins University, Baltimore, USA
| | - Chloe Liang
- Department of Biology, Johns Hopkins University, Baltimore, USA
| | - Chuofan Yu
- Department of Biology, Johns Hopkins University, Baltimore, USA
| | - Giho Park
- Department of Biology, Johns Hopkins University, Baltimore, USA
| | - Jeffry L Corden
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
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Rengachari S, Schilbach S, Cramer P. Mediator structure and function in transcription initiation. Biol Chem 2023; 404:829-837. [PMID: 37078249 DOI: 10.1515/hsz-2023-0158] [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: 03/10/2023] [Accepted: 04/06/2023] [Indexed: 04/21/2023]
Abstract
Recent advances in cryo-electron microscopy have led to multiple structures of Mediator in complex with the RNA polymerase II (Pol II) transcription initiation machinery. As a result we now hold in hands near-complete structures of both yeast and human Mediator complexes and have a better understanding of their interactions with the Pol II pre-initiation complex (PIC). Herein, we provide a summary of recent achievements and discuss their implications for future studies of Mediator and its role in gene regulation.
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Affiliation(s)
- Srinivasan Rengachari
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Sandra Schilbach
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
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Ang RML, Chen SAA, Kern AF, Xie Y, Fraser HB. Widespread epistasis among beneficial genetic variants revealed by high-throughput genome editing. CELL GENOMICS 2023; 3:100260. [PMID: 37082144 PMCID: PMC10112194 DOI: 10.1016/j.xgen.2023.100260] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/27/2022] [Accepted: 01/06/2023] [Indexed: 04/22/2023]
Abstract
The phenotypic effect of any genetic variant can be altered by variation at other genomic loci. Known as epistasis, these genetic interactions shape the genotype-phenotype map of every species, yet their origins remain poorly understood. To investigate this, we employed high-throughput genome editing to measure the fitness effects of 1,826 naturally polymorphic variants in four strains of Saccharomyces cerevisiae. About 31% of variants affect fitness, of which 24% have strain-specific fitness effects indicative of epistasis. We found that beneficial variants are more likely to exhibit genetic interactions and that these interactions can be mediated by specific traits such as flocculation ability. This work suggests that adaptive evolution will often involve trade-offs where a variant is only beneficial in some genetic backgrounds, potentially explaining why many beneficial variants remain polymorphic. In sum, we provide a framework to understand the factors influencing epistasis with single-nucleotide resolution, revealing widespread epistasis among beneficial variants.
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Affiliation(s)
- Roy Moh Lik Ang
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Shi-An A. Chen
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexander F. Kern
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Yihua Xie
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Hunter B. Fraser
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Corresponding author
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Raposo CJ, McElroy KA, Fuchs SM. The Epithelial adhesin 1 tandem repeat region mediates protein display through multiple mechanisms. FEMS Yeast Res 2020; 20:foaa018. [PMID: 32301985 PMCID: PMC7199969 DOI: 10.1093/femsyr/foaa018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/15/2020] [Indexed: 01/18/2023] Open
Abstract
The pathogenic yeast Candida glabrata is reliant on a suite of cell surface adhesins that play a variety of roles necessary for transmission, establishment and proliferation during infection. One particular adhesin, Epithelial Adhesin 1 [Epa1p], is responsible for binding to host tissue, a process which is essential for fungal propagation. Epa1p structure consists of three domains: an N-terminal intercellular binding domain responsible for epithelial cell binding, a C-terminal GPI anchor for cell wall linkage and a serine/threonine-rich linker domain connecting these terminal domains. The linker domain contains a 40-amino acid tandem repeat region, which we have found to be variable in repeat copy number between isolates from clinical sources. We hypothesized that natural variation in Epa1p repeat copy may modulate protein function. To test this, we recombinantly expressed Epa1p with various repeat copy numbers in S. cerevisiae to determine how differences in repeat copy number affect Epa1p expression, surface display and binding to human epithelial cells. Our data suggest that repeat copy number variation has pleiotropic effects, influencing gene expression, protein surface display and shedding from the cell surface of the Epa1p adhesin. This study serves to demonstrate repeat copy number variation can modulate protein function through a number of mechanisms in order to contribute to pathogenicity of C. glabrata.
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Affiliation(s)
- Colin J Raposo
- Department of Biology , Tufts University, 200 Boston Ave Suite 4700, Medford, MA, USA 01255
| | - Kyle A McElroy
- Department of Biology , Tufts University, 200 Boston Ave Suite 4700, Medford, MA, USA 01255
- Allen Discovery Center, Tufts University, 200 Boston Ave Suite 4600, Medford, MA 02155
| | - Stephen M Fuchs
- Department of Biology , Tufts University, 200 Boston Ave Suite 4700, Medford, MA, USA 01255
- Allen Discovery Center, Tufts University, 200 Boston Ave Suite 4600, Medford, MA 02155
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