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Gupta A, Kumar A, Singh N, Sudarshan N, Studitsky VM, Zhang KYJ, Akhtar MS. The Saccharomyces cerevisiae SR protein Npl3 interacts with hyperphosphorylated CTD of RNA Polymerase II. Int J Biol Macromol 2023; 253:127541. [PMID: 37858651 DOI: 10.1016/j.ijbiomac.2023.127541] [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: 07/26/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/21/2023]
Abstract
The catalytic subunit of RNA Polymerase II contains a highly conserved carboxy terminal domain (CTD) composed of multiple tandem heptad sequence Tyr1Ser2Pro3Thr4Ser5Pro6Ser7. The non-proline residues in CTD undergo posttranslational modifications, with Ser5 phosphorylation (Ser5P) predominating at the start of the transcription cycle and Ser2P at the end, while other phosphorylation levels are high all throughout. The differentially phosphorylated CTD is recognized by regulatory proteins, helpful during mRNA transcription and export. One such protein Npl3 is composed of two RNA binding domains and a C-terminus RGG/SR domain. The Ser411 of Npl3 is reported to make direct contact with Ser2P of CTD for its recruitment and function, while the Npl3 lacking of C-terminal 25 amino acids (Npl3Δ389-414) showed no apparent defects in mRNA synthesis. Here, we report that the RNA binding domains of Npl3 are separate folding units and interact also with the CTD. The interaction between Npl3 and CTD appears to involve not just Ser2P, but also the Ser5P and Ser7P. The Arg126 of the first RNA binding domain interacts with Ser2P whereas the Arg235 of the second RNA binding domain interacts with either Ser7P or Ser5P of another heptad. The finding provides new insight of Npl3 function for mRNA transcription.
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Affiliation(s)
- Adity Gupta
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ashutosh Kumar
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, 1-c7-22 Suehiro, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Neha Singh
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Nikita Sudarshan
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vasily M Studitsky
- Department of Bioengineering, School of Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Kam Y J Zhang
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, 1-c7-22 Suehiro, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Md Sohail Akhtar
- Biochemistry and Structural Biology Division, CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Miller CLW, Warner JL, Winston F. Insights into Spt6: a histone chaperone that functions in transcription, DNA replication, and genome stability. Trends Genet 2023; 39:858-872. [PMID: 37481442 PMCID: PMC10592469 DOI: 10.1016/j.tig.2023.06.008] [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: 05/19/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/24/2023]
Abstract
Transcription elongation requires elaborate coordination between the transcriptional machinery and chromatin regulatory factors to successfully produce RNA while preserving the epigenetic landscape. Recent structural and genomic studies have highlighted that suppressor of Ty 6 (Spt6), a conserved histone chaperone and transcription elongation factor, sits at the crux of the transcription elongation process. Other recent studies have revealed that Spt6 also promotes DNA replication and genome integrity. Here, we review recent studies of Spt6 that have provided new insights into the mechanisms by which Spt6 controls transcription and have revealed the breadth of Spt6 functions in eukaryotic cells.
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Affiliation(s)
- Catherine L W Miller
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Laboratory of Genome Maintenance, Rockefeller University, New York, NY 10065, USA
| | - James L Warner
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Fred Winston
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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3
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Kasiliauskaite A, Kubicek K, Klumpler T, Zanova M, Zapletal D, Koutna E, Novacek J, Stefl R. Cooperation between intrinsically disordered and ordered regions of Spt6 regulates nucleosome and Pol II CTD binding, and nucleosome assembly. Nucleic Acids Res 2022; 50:5961-5973. [PMID: 35640611 PMCID: PMC9177984 DOI: 10.1093/nar/gkac451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 04/29/2022] [Accepted: 05/16/2022] [Indexed: 11/14/2022] Open
Abstract
Transcription elongation factor Spt6 associates with RNA polymerase II (Pol II) and acts as a histone chaperone, which promotes the reassembly of nucleosomes following the passage of Pol II. The precise mechanism of nucleosome reassembly mediated by Spt6 remains unclear. In this study, we used a hybrid approach combining cryo-electron microscopy and small-angle X-ray scattering to visualize the architecture of Spt6 from Saccharomyces cerevisiae. The reconstructed overall architecture of Spt6 reveals not only the core of Spt6, but also its flexible N- and C-termini, which are critical for Spt6's function. We found that the acidic N-terminal region of Spt6 prevents the binding of Spt6 not only to the Pol II CTD and Pol II CTD-linker, but also to pre-formed intact nucleosomes and nucleosomal DNA. The N-terminal region of Spt6 self-associates with the tSH2 domain and the core of Spt6 and thus controls binding to Pol II and nucleosomes. Furthermore, we found that Spt6 promotes the assembly of nucleosomes in vitro. These data indicate that the cooperation between the intrinsically disordered and structured regions of Spt6 regulates nucleosome and Pol II CTD binding, and also nucleosome assembly.
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Affiliation(s)
- Aiste Kasiliauskaite
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Karel Kubicek
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic.,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - Tomas Klumpler
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic
| | - Martina Zanova
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic.,Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno CZ-61137, Czech Republic
| | - David Zapletal
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Eliska Koutna
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic.,Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jiri Novacek
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic
| | - Richard Stefl
- CEITEC-Central European Institute of Technology, Masaryk University, Brno CZ-62500, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
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LeBlanc BM, Moreno RY, Escobar EE, Venkat Ramani MK, Brodbelt JS, Zhang Y. What's all the phos about? Insights into the phosphorylation state of the RNA polymerase II C-terminal domain via mass spectrometry. RSC Chem Biol 2021; 2:1084-1095. [PMID: 34458825 PMCID: PMC8341212 DOI: 10.1039/d1cb00083g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022] Open
Abstract
RNA polymerase II (RNAP II) is one of the primary enzymes responsible for expressing protein-encoding genes and some small nuclear RNAs. The enigmatic carboxy-terminal domain (CTD) of RNAP II and its phosphorylation state are critically important in regulating transcription in vivo. Early methods of identifying phosphorylation on the CTD heptad were plagued by issues of low specificity and ambiguous signals. However, advancements in the field of mass spectrometry (MS) have presented the opportunity to gain new insights into well-studied processes as well as explore new frontiers in transcription. By using MS, residues which are modified within the CTD heptad and across repeats are now able to be pinpointed. Likewise, identification of kinase and phosphatase specificity towards residues of the CTD has reached a new level of accuracy. Now, MS is being used to investigate the crosstalk between modified residues of the CTD and may be a critical technique for understanding how phosphorylation plays a role in the new LLPS model of transcription. Herein, we discuss the development of various MS techniques and evaluate their capabilities. By highlighting the pros and cons of each technique, we aim to provide future investigators with a comprehensive overview of how MS can be used to investigate the complexities of RNAP-II mediated transcription.
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Affiliation(s)
- Blase M LeBlanc
- Department of Molecular Biosciences, University of Texas Austin USA
| | - R Yvette Moreno
- Department of Molecular Biosciences, University of Texas Austin USA
| | | | | | | | - Yan Zhang
- Department of Molecular Biosciences, University of Texas Austin USA
- Institute of Cellular and Molecular Biology, University of Texas Austin USA
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Venkat Ramani MK, Yang W, Irani S, Zhang Y. Simplicity is the Ultimate Sophistication-Crosstalk of Post-translational Modifications on the RNA Polymerase II. J Mol Biol 2021; 433:166912. [PMID: 33676925 PMCID: PMC8184622 DOI: 10.1016/j.jmb.2021.166912] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 12/19/2022]
Abstract
The highly conserved C-terminal domain (CTD) of the largest subunit of RNA polymerase II comprises a consensus heptad (Y1S2P3T4S5P6S7) repeated multiple times. Despite the simplicity of its sequence, the essential CTD domain orchestrates eukaryotic transcription and co-transcriptional processes, including transcription initiation, elongation, and termination, and mRNA processing. These distinct facets of the transcription cycle rely on specific post-translational modifications (PTM) of the CTD, in which five out of the seven residues in the heptad repeat are subject to phosphorylation. A hypothesis termed the "CTD code" has been proposed in which these PTMs and their combinations generate a sophisticated landscape for spatiotemporal recruitment of transcription regulators to Pol II. In this review, we summarize the recent experimental evidence understanding the biological role of the CTD, implicating a context-dependent theme that significantly enhances the ability of accurate transcription by RNA polymerase II. Furthermore, feedback communication between the CTD and histone modifications coordinates chromatin states with RNA polymerase II-mediated transcription, ensuring the effective and accurate conversion of information into cellular responses.
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Affiliation(s)
| | - Wanjie Yang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States
| | - Seema Irani
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States
| | - Yan Zhang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, United States; The Institute for Cellular and Molecular Biology. University of Texas at Austin, Austin, TX 78712, United States.
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Narain A, Bhandare P, Adhikari B, Backes S, Eilers M, Dölken L, Schlosser A, Erhard F, Baluapuri A, Wolf E. Targeted protein degradation reveals a direct role of SPT6 in RNAPII elongation and termination. Mol Cell 2021; 81:3110-3127.e14. [PMID: 34233157 PMCID: PMC8354102 DOI: 10.1016/j.molcel.2021.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 04/24/2021] [Accepted: 06/11/2021] [Indexed: 01/22/2023]
Abstract
SPT6 is a histone chaperone that tightly binds RNA polymerase II (RNAPII) during transcription elongation. However, its primary role in transcription is uncertain. We used targeted protein degradation to rapidly deplete SPT6 in human cells and analyzed defects in RNAPII behavior by a multi-omics approach and mathematical modeling. Our data indicate that SPT6 is a crucial factor for RNAPII processivity and is therefore required for the productive transcription of protein-coding genes. Unexpectedly, SPT6 also has a vital role in RNAPII termination, as acute depletion induced readthrough transcription for thousands of genes. Long-term depletion of SPT6 induced cryptic intragenic transcription, as observed earlier in yeast. However, this phenotype was not observed upon acute SPT6 depletion and therefore can be attributed to accumulated epigenetic perturbations in the prolonged absence of SPT6. In conclusion, targeted degradation of SPT6 allowed the temporal discrimination of its function as an epigenetic safeguard and RNAPII elongation factor. Auxin-inducible degradation discriminates direct roles of human SPT6 in transcription Acute loss of SPT6 globally impairs RNAPII processivity and speed SPT6 is required for efficient transcription termination on protein-coding genes Long-term loss of SPT6 ultimately results in cryptic intragenic transcription
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Affiliation(s)
- Ashwin Narain
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Pranjali Bhandare
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Bikash Adhikari
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Simone Backes
- Institute for Virology and Immunobiology, University of Würzburg, Versbacher Straße 7, 97078 Würzburg, Germany
| | - Martin Eilers
- Department of Biochemistry and Molecular Biology, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Lars Dölken
- Institute for Virology and Immunobiology, University of Würzburg, Versbacher Straße 7, 97078 Würzburg, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center, Center for Integrative and Translational Bioimaging, University of Würzburg, Josef-Schneider-Straße 2, 97080 Würzburg, Germany
| | - Florian Erhard
- Computational Systems Virology and Bioinformatics, Institute for Virology and Immunobiology, University of Würzburg, Versbacher Straße 7, 97078 Würzburg, Germany.
| | - Apoorva Baluapuri
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Elmar Wolf
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Am Hubland, 97074 Würzburg, Germany; Mildred Scheel Early Career Center, University of Würzburg, Beethovenstraße 1A, 97080 Würzburg, Germany.
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