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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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Liu L, Yu AM, Wang X, Soles LV, Teng X, Chen Y, Yoon Y, Sarkan KSK, Valdez MC, Linder J, England W, Spitale R, Yu Z, Marazzi I, Qiao F, Li W, Seelig G, Shi Y. The anticancer compound JTE-607 reveals hidden sequence specificity of the mRNA 3' processing machinery. Nat Struct Mol Biol 2023; 30:1947-1957. [PMID: 38087090 DOI: 10.1038/s41594-023-01161-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 10/24/2023] [Indexed: 12/18/2023]
Abstract
JTE-607 is an anticancer and anti-inflammatory compound and its active form, compound 2, directly binds to and inhibits CPSF73, the endonuclease for the cleavage step in pre-messenger RNA (pre-mRNA) 3' processing. Surprisingly, compound 2-mediated inhibition of pre-mRNA cleavage is sequence specific and the drug sensitivity is predominantly determined by sequences flanking the cleavage site (CS). Using massively parallel in vitro assays, we identified key sequence features that determine drug sensitivity. We trained a machine learning model that can predict poly(A) site (PAS) relative sensitivity to compound 2 and provide the molecular basis for understanding the impact of JTE-607 on PAS selection and transcription termination genome wide. We propose that CPSF73 and associated factors bind to the CS region in a sequence-dependent manner and the interaction affinity determines compound 2 sensitivity. These results have not only elucidated the mechanism of action of JTE-607, but also unveiled an evolutionarily conserved sequence specificity of the mRNA 3' processing machinery.
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Affiliation(s)
- Liang Liu
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
- Center for Virus Research, University of California, Irvine, Irvine, CA, USA
| | - Angela M Yu
- Department of Electrical and Computer Engineering, University of Washington, Seattle, Seattle, WA, USA
| | - Xiuye Wang
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
- Guangzhou Laboratory, Guangdong, China
| | - Lindsey V Soles
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Xueyi Teng
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Yiling Chen
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Yoseop Yoon
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Kristianna S K Sarkan
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Marielle Cárdenas Valdez
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Johannes Linder
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Whitney England
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, USA
| | - Robert Spitale
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, CA, USA
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, USA
| | - Zhaoxia Yu
- Department of Statistics, University of California, Irvine, Irvine, CA, USA
| | - Ivan Marazzi
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Feng Qiao
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Wei Li
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Georg Seelig
- Department of Electrical and Computer Engineering, University of Washington, Seattle, Seattle, WA, USA.
- Paul G Allen School of Computer Science and Engineering, University of Washington, Seattle, Seattle, WA, USA.
| | - Yongsheng Shi
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA, USA.
- Center for Virus Research, University of California, Irvine, Irvine, CA, USA.
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3
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Shen P, Ye K, Xiang H, Zhang Z, He Q, Zhang X, Cai MC, Chen J, Sun Y, Lin L, Qi C, Zhang M, Cheung LWT, Shi T, Yin X, Li Y, Di W, Zang R, Tan L, Zhuang G. Therapeutic targeting of CPSF3-dependent transcriptional termination in ovarian cancer. SCIENCE ADVANCES 2023; 9:eadj0123. [PMID: 37992178 PMCID: PMC10664987 DOI: 10.1126/sciadv.adj0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/19/2023] [Indexed: 11/24/2023]
Abstract
Transcriptional dysregulation is a recurring pathogenic hallmark and an emerging therapeutic vulnerability in ovarian cancer. Here, we demonstrated that ovarian cancer exhibited a unique dependency on the regulatory machinery of transcriptional termination, particularly, cleavage and polyadenylation specificity factor (CPSF) complex. Genetic abrogation of multiple CPSF subunits substantially hampered neoplastic cell viability, and we presented evidence that their indispensable roles converged on the endonuclease CPSF3. Mechanistically, CPSF perturbation resulted in lengthened 3'-untranslated regions, diminished intronic polyadenylation and widespread transcriptional readthrough, and consequently suppressed oncogenic pathways. Furthermore, we reported the development of specific CPSF3 inhibitors building upon the benzoxaborole scaffold, which exerted potent antitumor activity. Notably, CPSF3 blockade effectively exacerbated genomic instability by down-regulating DNA damage repair genes and thus acted in synergy with poly(adenosine 5'-diphosphate-ribose) polymerase inhibition. These findings establish CPSF3-dependent transcriptional termination as an exploitable driving mechanism of ovarian cancer and provide a promising class of boron-containing compounds for targeting transcription-addicted human malignancies.
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Affiliation(s)
- Peiye Shen
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Kaiyan Ye
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huaijiang Xiang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhenfeng Zhang
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qinyang He
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiao Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Mei-Chun Cai
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junfei Chen
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunheng Sun
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lifeng Lin
- Ovarian Cancer Program, Department of Gynecologic Oncology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Chunting Qi
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Meiying Zhang
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lydia W. T. Cheung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Tingyan Shi
- Ovarian Cancer Program, Department of Gynecologic Oncology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xia Yin
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Wen Di
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rongyu Zang
- Ovarian Cancer Program, Department of Gynecologic Oncology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Li Tan
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Guanglei Zhuang
- State Key Laboratory of Systems Medicine for Cancer, Department of Obstetrics and Gynecology, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Swale C, Hakimi MA. 3'-end mRNA processing within apicomplexan parasites, a patchwork of classic, and unexpected players. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1783. [PMID: 36994829 DOI: 10.1002/wrna.1783] [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: 08/25/2022] [Revised: 01/17/2023] [Accepted: 01/25/2023] [Indexed: 03/31/2023]
Abstract
The 3'-end processing of mRNA is a co-transcriptional process that leads to the formation of a poly-adenosine tail on the mRNA and directly controls termination of the RNA polymerase II juggernaut. This process involves a megadalton complex composed of cleavage and polyadenylation specificity factors (CPSFs) that are able to recognize cis-sequence elements on nascent mRNA to then carry out cleavage and polyadenylation reactions. Recent structural and biochemical studies have defined the roles played by different subunits of the complex and provided a comprehensive mechanistic understanding of this machinery in yeast or metazoans. More recently, the discovery of small molecule inhibitors of CPSF function in Apicomplexa has stimulated interest in studying the specificities of this ancient eukaryotic machinery in these organisms. Although its function is conserved in Apicomplexa, the CPSF complex integrates a novel reader of the N6-methyladenosine (m6A). This feature, inherited from the plant kingdom, bridges m6A metabolism directly to 3'-end processing and by extension, to transcription termination. In this review, we will examine convergence and divergence of CPSF within the apicomplexan parasites and explore the potential of small molecule inhibition of this machinery within these organisms. This article is categorized under: RNA Processing > 3' End Processing RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Grenoble Alpes University, Grenoble, France
| | - Mohamed-Ali Hakimi
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Grenoble Alpes University, Grenoble, France
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5
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Abstract
Formation of the 3' end of a eukaryotic mRNA is a key step in the production of a mature transcript. This process is mediated by a number of protein factors that cleave the pre-mRNA, add a poly(A) tail, and regulate transcription by protein dephosphorylation. Cleavage and polyadenylation specificity factor (CPSF) in humans, or cleavage and polyadenylation factor (CPF) in yeast, coordinates these enzymatic activities with each other, with RNA recognition, and with transcription. The site of pre-mRNA cleavage can strongly influence the translation, stability, and localization of the mRNA. Hence, cleavage site selection is highly regulated. The length of the poly(A) tail is also controlled to ensure that every transcript has a similar tail when it is exported from the nucleus. In this review, we summarize new mechanistic insights into mRNA 3'-end processing obtained through structural studies and biochemical reconstitution and outline outstanding questions in the field.
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Affiliation(s)
- Vytautė Boreikaitė
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom;
| | - Lori A Passmore
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom;
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Liu L, Yu AM, Wang X, Soles LV, Chen Y, Yoon Y, Sarkan KSK, Valdez MC, Linder J, Marazzi I, Yu Z, Qiao F, Li W, Seelig G, Shi Y. The anti-cancer compound JTE-607 reveals hidden sequence specificity of the mRNA 3' processing machinery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536453. [PMID: 37090613 PMCID: PMC10120630 DOI: 10.1101/2023.04.11.536453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
JTE-607 is a small molecule compound with anti-inflammation and anti-cancer activities. Upon entering the cell, it is hydrolyzed to Compound 2, which directly binds to and inhibits CPSF73, the endonuclease for the cleavage step in pre-mRNA 3' processing. Although CPSF73 is universally required for mRNA 3' end formation, we have unexpectedly found that Compound 2- mediated inhibition of pre-mRNA 3' processing is sequence-specific and that the sequences flanking the cleavage site (CS) are a major determinant for drug sensitivity. By using massively parallel in vitro assays, we have measured the Compound 2 sensitivities of over 260,000 sequence variants and identified key sequence features that determine drug sensitivity. A machine learning model trained on these data can predict the impact of JTE-607 on poly(A) site (PAS) selection and transcription termination genome-wide. We propose a biochemical model in which CPSF73 and other mRNA 3' processing factors bind to RNA of the CS region in a sequence-specific manner and the affinity of such interaction determines the Compound 2 sensitivity of a PAS. As the Compound 2-resistant CS sequences, characterized by U/A-rich motifs, are prevalent in PASs from yeast to human, the CS region sequence may have more fundamental functions beyond determining drug resistance. Together, our study not only characterized the mechanism of action of a compound with clinical implications, but also revealed a previously unknown and evolutionarily conserved sequence-specificity of the mRNA 3' processing machinery.
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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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RBBP6 activates the pre-mRNA 3' end processing machinery in humans. Genes Dev 2022; 36:210-224. [PMID: 35177536 PMCID: PMC8887125 DOI: 10.1101/gad.349223.121] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/01/2022] [Indexed: 11/25/2022]
Abstract
In this study, Boreikaite et al. reconstituted specific and efficient 3′ endonuclease activity of human CPSF with purified proteins. This required the seven-subunit CPSF as well as three additional protein factors: cleavage stimulatory factor (CStF), cleavage factor IIm (CFIIm), and, importantly, the multidomain protein RBBP6. 3′ end processing of most human mRNAs is carried out by the cleavage and polyadenylation specificity factor (CPSF; CPF in yeast). Endonucleolytic cleavage of the nascent pre-mRNA defines the 3′ end of the mature transcript, which is important for mRNA localization, translation, and stability. Cleavage must therefore be tightly regulated. Here, we reconstituted specific and efficient 3′ endonuclease activity of human CPSF with purified proteins. This required the seven-subunit CPSF as well as three additional protein factors: cleavage stimulatory factor (CStF), cleavage factor IIm (CFIIm), and, importantly, the multidomain protein RBBP6. Unlike its yeast homolog Mpe1, which is a stable subunit of CPF, RBBP6 does not copurify with CPSF and is recruited in an RNA-dependent manner. Sequence and mutational analyses suggest that RBBP6 interacts with the WDR33 and CPSF73 subunits of CPSF. Thus, it is likely that the role of RBBP6 is conserved from yeast to humans. Overall, our data are consistent with CPSF endonuclease activation and site-specific pre-mRNA cleavage being highly controlled to maintain fidelity in mRNA processing.
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