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Alahmari AA, Chaubey AH, Jonnakuti VS, Tisdale AA, Schwarz CD, Cornwell AC, Maraszek KE, Paterson EJ, Kim M, Venkat S, Gomez EC, Wang J, Gurova KV, Yalamanchili HK, Feigin ME. CPSF3 inhibition blocks pancreatic cancer cell proliferation through disruption of core histone mRNA processing. RNA (NEW YORK, N.Y.) 2024; 30:281-297. [PMID: 38191171 PMCID: PMC10870380 DOI: 10.1261/rna.079931.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 01/10/2024]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with limited effective treatment options, potentiating the importance of uncovering novel drug targets. Here, we target cleavage and polyadenylation specificity factor 3 (CPSF3), the 3' endonuclease that catalyzes mRNA cleavage during polyadenylation and histone mRNA processing. We find that CPSF3 is highly expressed in PDAC and is associated with poor prognosis. CPSF3 knockdown blocks PDAC cell proliferation and colony formation in vitro and tumor growth in vivo. Chemical inhibition of CPSF3 by the small molecule JTE-607 also attenuates PDAC cell proliferation and colony formation, while it has no effect on cell proliferation of nontransformed immortalized control pancreatic cells. Mechanistically, JTE-607 induces transcriptional readthrough in replication-dependent histones, reduces core histone expression, destabilizes chromatin structure, and arrests cells in the S-phase of the cell cycle. Therefore, CPSF3 represents a potential therapeutic target for the treatment of PDAC.
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Affiliation(s)
- Abdulrahman A Alahmari
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
| | - Aditi H Chaubey
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Venkata S Jonnakuti
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Program in Quantitative and Computational Biology, Baylor College of Medicine, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Arwen A Tisdale
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Carla D Schwarz
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Abigail C Cornwell
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Kathryn E Maraszek
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Emily J Paterson
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Minsuh Kim
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Swati Venkat
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Eduardo Cortes Gomez
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Jianmin Wang
- Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Katerina V Gurova
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
| | - Hari Krishna Yalamanchili
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Michael E Feigin
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14203, USA
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Geisler MS, Kemp JP, Duronio RJ. Histone locus bodies: a paradigm for how nuclear biomolecular condensates control cell cycle regulated gene expression. Nucleus 2023; 14:2293604. [PMID: 38095604 PMCID: PMC10730174 DOI: 10.1080/19491034.2023.2293604] [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: 09/29/2023] [Accepted: 12/07/2023] [Indexed: 12/18/2023] Open
Abstract
Histone locus bodies (HLBs) are biomolecular condensates that assemble at replication-dependent (RD) histone genes in animal cells. These genes produce unique mRNAs that are not polyadenylated and instead end in a conserved 3' stem loop critical for coordinated production of histone proteins during S phase of the cell cycle. Several evolutionarily conserved factors necessary for synthesis of RD histone mRNAs concentrate only in the HLB. Moreover, because HLBs are present throughout the cell cycle even though RD histone genes are only expressed during S phase, changes in HLB composition during cell cycle progression drive much of the cell cycle regulation of RD histone gene expression. Thus, HLBs provide a powerful opportunity to determine the cause-and-effect relationships between nuclear body formation and cell cycle regulated gene expression. In this review, we focus on progress during the last five years that has advanced our understanding of HLB biology.
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Affiliation(s)
- Mark S. Geisler
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
| | - James P. Kemp
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Robert J. Duronio
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
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Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. RNA (NEW YORK, N.Y.) 2023; 29:1673-1690. [PMID: 37562960 PMCID: PMC10578488 DOI: 10.1261/rna.079709.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023]
Abstract
U7 snRNP is a multisubunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B, and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50, and pICln known to methylate arginines in the carboxy-terminal regions of the Sm proteins B, D1, and D3 during the spliceosomal Sm ring assembly. Both biochemical and cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the amino-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an amino-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
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Affiliation(s)
- Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Anthony Desotell
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Min-Han Lin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Andrew S Paige
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Agata Malinowska
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Michał Dadlez
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Warsaw University, 02-106 Warsaw, Poland
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540203. [PMID: 37215023 PMCID: PMC10197641 DOI: 10.1101/2023.05.10.540203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
U7 snRNP is a multi-subunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50 and pICln known to methylate arginines in the C-terminal regions of the Sm proteins B, D1 and D3 during the spliceosomal Sm ring assembly. Both biochemical and Cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the N-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an N-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
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Huang J, Liu X, Sun Y, Li Z, Lin MH, Hamilton K, Mandel CR, Sandmeir F, Conti E, Oyala PH, Tong L. An examination of the metal ion content in the active sites of human endonucleases CPSF73 and INTS11. J Biol Chem 2023; 299:103047. [PMID: 36822327 PMCID: PMC10064220 DOI: 10.1016/j.jbc.2023.103047] [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: 01/19/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/23/2023] Open
Abstract
Human cleavage and polyadenylation specificity factor (CPSF)73 (also known as CPSF3) is the endoribonuclease that catalyzes the cleavage reaction for the 3'-end processing of pre-mRNAs. The active site of CPSF73 is located at the interface between a metallo-β-lactamase domain and a β-CASP domain. Two metal ions are coordinated by conserved residues, five His and two Asp, in the active site, and they are critical for the nuclease reaction. The metal ions have long been thought to be zinc ions, but their exact identity has not been examined. Here we present evidence from inductively coupled plasma mass spectrometry and X-ray diffraction analyses that a mixture of metal ions, including Fe, Zn, and Mn, is present in the active site of CPSF73. The abundance of the various metal ions is different in samples prepared from different expression hosts. Zinc is present at less than 20% abundance in a sample expressed in insect cells, but the sample is active in cleaving a pre-mRNA substrate in a reconstituted canonical 3'-end processing machinery. Zinc is present at 75% abundance in a sample expressed in human cells, which has comparable endonuclease activity. We also observe a mixture of metal ions in the active site of the CPSF73 homolog INTS11, the endonuclease for Integrator. Taken together, our results provide further insights into the role of metal ions in the activity of CPSF73 and INTS11 for RNA 3'-end processing.
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Affiliation(s)
- Ji Huang
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Xiangyang Liu
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Zhuang Li
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Min-Han Lin
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Keith Hamilton
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Corey R Mandel
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Felix Sandmeir
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York, USA.
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Zhang G, Luo H, Li X, Hu Z, Wang Q. The Dynamic Poly(A) Tail Acts as a Signal Hub in mRNA Metabolism. Cells 2023; 12:cells12040572. [PMID: 36831239 PMCID: PMC9954528 DOI: 10.3390/cells12040572] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/19/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
In eukaryotes, mRNA metabolism requires a sophisticated signaling system. Recent studies have suggested that polyadenylate tail may play a vital role in such a system. The poly(A) tail used to be regarded as a common modification at the 3' end of mRNA, but it is now known to be more than just that. It appears to act as a platform or hub that can be understood in two ways. On the one hand, polyadenylation and deadenylation machinery constantly regulates its dynamic activity; on the other hand, it exhibits the ability to recruit RNA-binding proteins and then interact with diverse factors to send various signals to regulate mRNA metabolism. In this paper, we outline the main complexes that regulate the dynamic activities of poly(A) tails, explain how these complexes participate polyadenylation/deadenylation process and summarize the diverse signals this hub emit. We are trying to make a point that the poly(A) tail can metaphorically act as a "flagman" who is supervised by polyadenylation and deadenylation and sends out signals to regulate the orderly functioning of mRNA metabolism.
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Affiliation(s)
- Guiying Zhang
- Guangdong Technology Research Center for Marine Algal Bioengineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Haolin Luo
- Guangdong Technology Research Center for Marine Algal Bioengineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
| | - Xinyi Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
| | - Zhangli Hu
- Guangdong Technology Research Center for Marine Algal Bioengineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
- Correspondence: (Z.H.); (Q.W.)
| | - Quan Wang
- Guangdong Technology Research Center for Marine Algal Bioengineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning 437100, China
- Correspondence: (Z.H.); (Q.W.)
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Knowing when to stop: Transcription termination on protein-coding genes by eukaryotic RNAPII. Mol Cell 2023; 83:404-415. [PMID: 36634677 PMCID: PMC7614299 DOI: 10.1016/j.molcel.2022.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023]
Abstract
Gene expression is controlled in a dynamic and regulated manner to allow for the consistent and steady expression of some proteins as well as the rapidly changing production of other proteins. Transcription initiation has been a major focus of study because it is highly regulated. However, termination of transcription also plays an important role in controlling gene expression. Transcription termination on protein-coding genes is intimately linked with 3' end cleavage and polyadenylation of transcripts, and it generally results in the production of a mature mRNA that is exported from the nucleus. Termination on many non-coding genes can also result in the production of a mature transcript. Termination is dynamically regulated-premature termination and transcription readthrough occur in response to a number of cellular signals, and these can have varied consequences on gene expression. Here, we review eukaryotic transcription termination by RNA polymerase II (RNAPII), focusing on protein-coding genes.
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Ielasi FS, Ternifi S, Fontaine E, Iuso D, Couté Y, Palencia A. Human histone pre-mRNA assembles histone or canonical mRNA-processing complexes by overlapping 3'-end sequence elements. Nucleic Acids Res 2022; 50:12425-12443. [PMID: 36447390 PMCID: PMC9756948 DOI: 10.1093/nar/gkac878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 09/20/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Human pre-mRNA processing relies on multi-subunit macromolecular complexes, which recognize specific RNA sequence elements essential for assembly and activity. Canonical pre-mRNA processing proceeds via the recognition of a polyadenylation signal (PAS) and a downstream sequence element (DSE), and produces polyadenylated mature mRNAs, while replication-dependent (RD) histone pre-mRNA processing requires association with a stem-loop (SL) motif and a histone downstream element (HDE), and produces cleaved but non-polyadenylated mature mRNAs. H2AC18 mRNA, a specific H2A RD histone pre-mRNA, can be processed to give either a non-polyadenylated mRNA, ending at the histone SL, or a polyadenylated mRNA. Here, we reveal how H2AC18 captures the two human pre-mRNA processing complexes in a mutually exclusive mode by overlapping a canonical PAS (AAUAAA) sequence element with a HDE. Disruption of the PAS sequence on H2AC18 pre-mRNA prevents recruitment of the canonical complex in vitro, without affecting the histone machinery. This shows how the relative position of cis-acting elements in histone pre-mRNAs allows the selective recruitment of distinct human pre-mRNA complexes, thereby expanding the capability to regulate 3' processing and polyadenylation.
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Affiliation(s)
- Francesco S Ielasi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Sara Ternifi
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Emeline Fontaine
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Targets in Human Diseases, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Domenico Iuso
- Institute for Advanced Biosciences (IAB), Epigenetics and Cell Signaling, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Andrés Palencia
- To whom correspondence should be addressed. Tel: +33 476 54 95 75;
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Cortazar MA, Erickson B, Fong N, Pradhan SJ, Ntini E, Bentley DL. Xrn2 substrate mapping identifies torpedo loading sites and extensive premature termination of RNA pol II transcription. Genes Dev 2022; 36:1062-1078. [PMID: 36396340 PMCID: PMC9744234 DOI: 10.1101/gad.350004.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022]
Abstract
The exonuclease torpedo Xrn2 loads onto nascent RNA 5'-PO4 ends and chases down pol II to promote termination downstream from polyA sites. We report that Xrn2 is recruited to preinitiation complexes and "travels" to 3' ends of genes. Mapping of 5'-PO4 ends in nascent RNA identified Xrn2 loading sites stabilized by an active site mutant, Xrn2(D235A). Xrn2 loading sites are approximately two to 20 bases downstream from where CPSF73 cleaves at polyA sites and histone 3' ends. We propose that processing of all mRNA 3' ends comprises cleavage and limited 5'-3' trimming by CPSF73, followed by handoff to Xrn2. A similar handoff occurs at tRNA 3' ends, where cotranscriptional RNase Z cleavage generates novel Xrn2 substrates. Exonuclease-dead Xrn2 increased transcription in 3' flanking regions by inhibiting polyA site-dependent termination. Surprisingly, the mutant Xrn2 also rescued transcription in promoter-proximal regions to the same extent as in 3' flanking regions. eNET-seq revealed Xrn2-mediated degradation of sense and antisense nascent RNA within a few bases of the TSS, where 5'-PO4 ends may be generated by decapping or endonucleolytic cleavage. These results suggest that a major fraction of pol II complexes terminates prematurely close to the start site under normal conditions by an Xrn2-mediated torpedo mechanism.
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Affiliation(s)
- Michael A. Cortazar
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin Erickson
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Nova Fong
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Sarala J. Pradhan
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Evgenia Ntini
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas (FORTH), Heraklion GR-70013, Greece
| | - David L. Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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Liu J, Lu X, Zhang S, Yuan L, Sun Y. Molecular Insights into mRNA Polyadenylation and Deadenylation. Int J Mol Sci 2022; 23:ijms231910985. [PMID: 36232288 PMCID: PMC9570436 DOI: 10.3390/ijms231910985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 08/31/2022] [Accepted: 09/06/2022] [Indexed: 11/28/2022] Open
Abstract
Poly(A) tails are present on almost all eukaryotic mRNAs, and play critical roles in mRNA stability, nuclear export, and translation efficiency. The biosynthesis and shortening of a poly(A) tail are regulated by large multiprotein complexes. However, the molecular mechanisms of these protein machineries still remain unclear. Recent studies regarding the structural and biochemical characteristics of those protein complexes have shed light on the potential mechanisms of polyadenylation and deadenylation. This review summarizes the recent structural studies on pre-mRNA 3′-end processing complexes that initiate the polyadenylation and discusses the similarities and differences between yeast and human machineries. Specifically, we highlight recent biochemical efforts in the reconstitution of the active human canonical pre-mRNA 3′-end processing systems, as well as the roles of RBBP6/Mpe1 in activating the entire machinery. We also describe how poly(A) tails are removed by the PAN2-PAN3 and CCR4-NOT deadenylation complexes and discuss the emerging role of the cytoplasmic poly(A)-binding protein (PABPC) in promoting deadenylation. Together, these recent discoveries show that the dynamic features of these machineries play important roles in regulating polyadenylation and deadenylation.
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Schmidt M, Kluge F, Sandmeir F, Kühn U, Schäfer P, Tüting C, Ihling C, Conti E, Wahle E. Reconstitution of 3' end processing of mammalian pre-mRNA reveals a central role of RBBP6. Genes Dev 2022; 36:195-209. [PMID: 35177537 PMCID: PMC8887130 DOI: 10.1101/gad.349217.121] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/21/2022] [Indexed: 11/24/2022]
Abstract
Here, Schmidt et al. reconstituted the endonucleolytic cleavage of an extended precursor followed by the addition of a poly(A) tail reaction from overproduced and purified proteins, and provide a minimal list of 14 polypeptides that are essential and two that are stimulatory for RNA processing. The 3′ ends of almost all eukaryotic mRNAs are generated in an essential two-step processing reaction: endonucleolytic cleavage of an extended precursor followed by the addition of a poly(A) tail. By reconstituting the reaction from overproduced and purified proteins, we provide a minimal list of 14 polypeptides that are essential and two that are stimulatory for RNA processing. In a reaction depending on the polyadenylation signal AAUAAA, the reconstituted system cleaves pre-mRNA at a single preferred site corresponding to the one used in vivo. Among the proteins, cleavage factor I stimulates cleavage but is not essential, consistent with its prominent role in alternative polyadenylation. RBBP6 is required, with structural data showing it to contact and presumably activate the endonuclease CPSF73 through its DWNN domain. The C-terminal domain of RNA polymerase II is dispensable. ATP, but not its hydrolysis, supports RNA cleavage by binding to the hClp1 subunit of cleavage factor II with submicromolar affinity.
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Affiliation(s)
- Moritz Schmidt
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Florian Kluge
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Felix Sandmeir
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Uwe Kühn
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Peter Schäfer
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Christian Tüting
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Christian Ihling
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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Wiedermannová J, Krásný L. β-CASP proteins removing RNA polymerase from DNA: when a torpedo is needed to shoot a sitting duck. Nucleic Acids Res 2021; 49:10221-10234. [PMID: 34551438 PMCID: PMC8501993 DOI: 10.1093/nar/gkab803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022] Open
Abstract
During the first step of gene expression, RNA polymerase (RNAP) engages DNA to transcribe RNA, forming highly stable complexes. These complexes need to be dissociated at the end of transcription units or when RNAP stalls during elongation and becomes an obstacle (‘sitting duck’) to further transcription or replication. In this review, we first outline the mechanisms involved in these processes. Then, we explore in detail the torpedo mechanism whereby a 5′–3′ RNA exonuclease (torpedo) latches itself onto the 5′ end of RNA protruding from RNAP, degrades it and upon contact with RNAP, induces dissociation of the complex. This mechanism, originally described in Eukaryotes and executed by Xrn-type 5′–3′ exonucleases, was recently found in Bacteria and Archaea, mediated by β-CASP family exonucleases. We discuss the mechanistic aspects of this process across the three kingdoms of life and conclude that 5′–3′ exoribonucleases (β-CASP and Xrn families) involved in the ancient torpedo mechanism have emerged at least twice during evolution.
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Affiliation(s)
- Jana Wiedermannová
- Correspondence may also be addressed to Jana Wiedermannová. Tel: +44 191 208 3226; Fax: +44 191 208 3205;
| | - Libor Krásný
- To whom correspondence should be addressed. Tel: +420 241063208;
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Gutierrez PA, Baughman K, Sun Y, Tong L. A real-time fluorescence assay for CPSF73, the nuclease for pre-mRNA 3'-end processing. RNA (NEW YORK, N.Y.) 2021; 27:1148-1154. [PMID: 34230059 PMCID: PMC8457007 DOI: 10.1261/rna.078764.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/17/2021] [Indexed: 05/09/2023]
Abstract
CPSF73 is the endonuclease that catalyzes the cleavage reaction for 3'-end processing of mRNA precursors (pre-mRNAs) in two distinct machineries, a canonical machinery for the majority of pre-mRNAs and a U7 snRNP (U7 machinery) for replication-dependent histone pre-mRNAs in animal cells. CPSF73 also possesses 5'-3' exonuclease activity in the U7 machinery, degrading the downstream cleavage product after the endonucleolytic cleavage. Recent studies show that CPSF73 is a potential target for developing anticancer, antimalarial, and antiprotozoal drugs, spurring interest in identifying new small-molecule inhibitors against this enzyme. CPSF73 nuclease activity has so far been demonstrated using a gel-based end-point assay, using radiolabeled or fluorescently labeled RNA substrates. By taking advantage of unique properties of the U7 machinery, we have developed a novel, real-time fluorescence assay for the nuclease activity of CPSF73. This assay is facile and high-throughput, and should also be helpful for the discovery of new CPSF73 inhibitors.
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Affiliation(s)
- Pedro A Gutierrez
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Kirk Baughman
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Liu H, Moore CL. On the Cutting Edge: Regulation and Therapeutic Potential of the mRNA 3' End Nuclease. Trends Biochem Sci 2021; 46:772-784. [PMID: 33941430 PMCID: PMC8364479 DOI: 10.1016/j.tibs.2021.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/18/2021] [Accepted: 04/02/2021] [Indexed: 12/24/2022]
Abstract
Cleavage of nascent transcripts is a fundamental process for eukaryotic mRNA maturation and for the production of different mRNA isoforms. In eukaryotes, cleavage of mRNA precursors by the highly conserved endonuclease CPSF73 is critical for mRNA stability, export from the nucleus, and translation. As an essential enzyme in the cell, CPSF73 surprisingly shows promise as a drug target for specific cancers and for protozoan parasites. In this review, we cover our current understanding of CPSF73 in cleavage and polyadenylation, histone pre-mRNA processing, and transcription termination. We discuss the potential of CPSF73 as a target for novel therapeutics and highlight further research into the regulation of CPSF73 that will be critical to understanding its role in cancer and other diseases.
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Affiliation(s)
- Huiyun Liu
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Claire L Moore
- Department of Developmental, Molecular, and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
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U7 deciphered: the mechanism that forms the unusual 3' end of metazoan replication-dependent histone mRNAs. Biochem Soc Trans 2021; 49:2229-2240. [PMID: 34351387 DOI: 10.1042/bst20210323] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 11/17/2022]
Abstract
In animal cells, replication-dependent histone mRNAs end with a highly conserved stem-loop structure followed by a 4- to 5-nucleotide single-stranded tail. This unique 3' end distinguishes replication-dependent histone mRNAs from all other eukaryotic mRNAs, which end with a poly(A) tail produced by the canonical 3'-end processing mechanism of cleavage and polyadenylation. The pioneering studies of Max Birnstiel's group demonstrated nearly 40 years ago that the unique 3' end of animal replication-dependent histone mRNAs is generated by a distinct processing mechanism, whereby histone mRNA precursors are cleaved downstream of the stem-loop, but this cleavage is not followed by polyadenylation. The key role is played by the U7 snRNP, a complex of a ∼60 nucleotide U7 snRNA and many proteins. Some of these proteins, including the enzymatic component CPSF73, are shared with the canonical cleavage and polyadenylation machinery, justifying the view that the two metazoan pre-mRNA 3'-end processing mechanisms have a common evolutionary origin. The studies on U7 snRNP culminated in the recent breakthrough of reconstituting an entirely recombinant human machinery that is capable of accurately cleaving histone pre-mRNAs, and determining its structure in complex with a pre-mRNA substrate (with 13 proteins and two RNAs) that is poised for the cleavage reaction. The structure uncovered an unanticipated network of interactions within the U7 snRNP and a remarkable mechanism of activating catalytically dormant CPSF73 for the cleavage. This work provides a conceptual framework for understanding other eukaryotic 3'-end processing machineries.
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Sun Y, Aik WS, Yang XC, Marzluff WF, Dominski Z, Tong L. Reconstitution and biochemical assays of an active human histone pre-mRNA 3'-end processing machinery. Methods Enzymol 2021; 655:291-324. [PMID: 34183127 DOI: 10.1016/bs.mie.2021.03.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In animal cells, replication-dependent histone pre-mRNAs are processed at the 3'-end by an endonucleolytic cleavage carried out by the U7 snRNP, a machinery that contains the U7 snRNA and many protein subunits. Studies on the composition of this machinery and understanding of its role in 3'-end processing were greatly facilitated by the development of an in vitro system utilizing nuclear extracts from mammalian cells 35 years ago and later from Drosophila cells. Most recently, recombinant expression and purification of the components of the machinery have enabled the full reconstitution of an active machinery and its complex with a model pre-mRNA substrate, using 13 proteins and 2 RNAs, and the determination of the structure of this active machinery. This chapter presents protocols for preparing nuclear extracts containing endogenous processing machinery, for assembling semi-recombinant and fully reconstituted machineries, and for histone pre-mRNA 3'-end processing assays with these samples.
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Affiliation(s)
- Yadong Sun
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William F Marzluff
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, United States.
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Comparative parallel analysis of RNA ends identifies mRNA substrates of a tRNA splicing endonuclease-initiated mRNA decay pathway. Proc Natl Acad Sci U S A 2021; 118:2020429118. [PMID: 33649230 DOI: 10.1073/pnas.2020429118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Eukaryotes share a conserved messenger RNA (mRNA) decay pathway in which bulk mRNA is degraded by exoribonucleases. In addition, it has become clear that more specialized mRNA decay pathways are initiated by endonucleolytic cleavage at particular sites. The transfer RNA (tRNA) splicing endonuclease (TSEN) has been studied for its ability to remove introns from pre-tRNAs. More recently it has been shown that single amino acid mutations in TSEN cause pontocerebellar hypoplasia. Other recent studies indicate that TSEN has other functions, but the nature of these functions has remained obscure. Here we show that yeast TSEN cleaves a specific subset of mRNAs that encode mitochondrial proteins, and that the cleavage sites are in part determined by their sequence. This provides an explanation for the counterintuitive mitochondrial localization of yeast TSEN. To identify these mRNA target sites, we developed a "comPARE" (comparative parallel analysis of RNA ends) bioinformatic approach that should be easily implemented and widely applicable to the study of endoribonucleases. The similarity of tRNA endonuclease-initiated decay to regulated IRE1-dependent decay of mRNA suggests that mRNA specificity by colocalization may be an important determinant for the degradation of localized mRNAs in a variety of eukaryotic cells.
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