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Torres-Dowdall J, Karagic N, Prabhukumar F, Meyer A. Differential Regulation of Opsin Gene Expression in Response to Internal and External Stimuli. Genome Biol Evol 2024; 16:evae125. [PMID: 38860496 DOI: 10.1093/gbe/evae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 05/24/2024] [Accepted: 06/01/2024] [Indexed: 06/12/2024] Open
Abstract
Determining how internal and external stimuli interact to determine developmental trajectories of traits is a challenge that requires the integration of different subfields of biology. Internal stimuli, such as hormones, control developmental patterns of phenotypic changes, which might be modified by external environmental cues (e.g. plasticity). Thyroid hormone (TH) modulates the timing of opsin gene expression in developing Midas cichlid fish (Amphilophus citrinellus). Moreover, fish reared in red light accelerate this developmental timing compared to fish reared in white light. Hence, we hypothesized that plasticity caused by variation in light conditions has coopted the TH signaling pathway to induce changes in opsin gene expression. We treated Midas cichlids with TH and crossed this treatment with two light conditions, white and red. We observed that not only opsin expression responded similarly to TH and red light but also that, at high TH levels, there is limited capacity for light-induced plasticity. Transcriptomic analysis of the eye showed that genes in the TH pathway were affected by TH, but not by light treatments. Coexpression network analyses further suggested that response to light was independent of the response to TH manipulations. Taken together, our results suggest independent mechanisms mediating development and plasticity during development of opsin gene expression, and that responses to environmental stimuli may vary depending on internal stimuli. This conditional developmental response to external factors depending on internal ones (e.g. hormones) might play a fundamental role in the patterns of phenotypic divergence observed in Midas cichlids and potentially other organisms.
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Affiliation(s)
- Julián Torres-Dowdall
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Nidal Karagic
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Femina Prabhukumar
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
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2
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Elvira-Blázquez D, Fernández-Justel JM, Arcas A, Statello L, Goñi E, González J, Ricci B, Zaccara S, Raimondi I, Huarte M. YTHDC1 m 6A-dependent and m 6A-independent functions converge to preserve the DNA damage response. EMBO J 2024:10.1038/s44318-024-00153-x. [PMID: 38951610 DOI: 10.1038/s44318-024-00153-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 05/07/2024] [Accepted: 06/05/2024] [Indexed: 07/03/2024] Open
Abstract
Cells have evolved a robust and highly regulated DNA damage response to preserve their genomic integrity. Although increasing evidence highlights the relevance of RNA regulation, our understanding of its impact on a fully efficient DNA damage response remains limited. Here, through a targeted CRISPR-knockout screen, we identify RNA-binding proteins and modifiers that participate in the p53 response. Among the top hits, we find the m6A reader YTHDC1 as a master regulator of p53 expression. YTHDC1 binds to the transcription start sites of TP53 and other genes involved in the DNA damage response, promoting their transcriptional elongation. YTHDC1 deficiency also causes the retention of introns and therefore aberrant protein production of key DNA damage factors. While YTHDC1-mediated intron retention requires m6A, TP53 transcriptional pause-release is promoted by YTHDC1 independently of m6A. Depletion of YTHDC1 causes genomic instability and aberrant cancer cell proliferation mediated by genes regulated by YTHDC1. Our results uncover YTHDC1 as an orchestrator of the DNA damage response through distinct mechanisms of co-transcriptional mRNA regulation.
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Affiliation(s)
- Daniel Elvira-Blázquez
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
| | - José Miguel Fernández-Justel
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
| | - Aida Arcas
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
- Clarivate, Barcelona, Spain
| | - Luisa Statello
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
| | - Enrique Goñi
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
| | - Jovanna González
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain
| | - Benedetta Ricci
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Sara Zaccara
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Ivan Raimondi
- New York Genome Center, New York, NY, USA.
- Weill Cornell Medicine, New York, NY, USA.
| | - Maite Huarte
- Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain.
- Institute of Health Research of Navarra (IdiSNA), Pamplona, Spain.
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3
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Merens HE, Choquet K, Baxter-Koenigs AR, Churchman LS. Timing is everything: advances in quantifying splicing kinetics. Trends Cell Biol 2024:S0962-8924(24)00070-9. [PMID: 38777664 DOI: 10.1016/j.tcb.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 05/25/2024]
Abstract
Splicing is a highly regulated process critical for proper pre-mRNA maturation and the maintenance of a healthy cellular environment. Splicing events are impacted by ongoing transcription, neighboring splicing events, and cis and trans regulatory factors on the respective pre-mRNA transcript. Within this complex regulatory environment, splicing kinetics have the potential to influence splicing outcomes but have historically been challenging to study in vivo. In this review, we highlight recent technological advancements that have enabled measurements of global splicing kinetics and of the variability of splicing kinetics at single introns. We demonstrate how identifying features that are correlated with splicing kinetics has increased our ability to form potential models for how splicing kinetics may be regulated in vivo.
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Affiliation(s)
- Hope E Merens
- Harvard University, Department of Genetics, Boston, MA, USA
| | - Karine Choquet
- University of Sherbrooke, Department of Biochemistry and Functional Genomics, Sherbrooke, Québec, Canada
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4
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Yustis JC, Devoucoux M, Côté J. The Functional Relationship Between RNA Splicing and the Chromatin Landscape. J Mol Biol 2024:168614. [PMID: 38762032 DOI: 10.1016/j.jmb.2024.168614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/27/2024] [Accepted: 05/13/2024] [Indexed: 05/20/2024]
Abstract
Chromatin is a highly regulated and dynamic structure that has been shown to play an essential role in transcriptional and co-transcriptional regulation. In the context of RNA splicing, early evidence suggested a loose connection between the chromatin landscape and splicing. More recently, it has been shown that splicing occurs in a co-transcriptional manner, meaning that the splicing process occurs in the context of chromatin. Experimental and computational evidence have also shown that chromatin dynamics can influence the splicing process and vice versa. However, much of this evidence provides mainly correlative relationships between chromatin and splicing with just a few concrete examples providing defined molecular mechanisms by which these two processes are functionally related. Nevertheless, it is clear that chromatin and RNA splicing are tightly interconnected to one another. In this review, we highlight the current state of knowledge of the relationship between chromatin and splicing.
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Affiliation(s)
- Juan-Carlos Yustis
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Maëva Devoucoux
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Oncology Division of the CHU de Québec-Université Laval Research Center, Quebec City, Quebec G1R 3S3, Canada.
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5
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Dhahri H, Fondufe-Mittendorf YN. Exploring the interplay between PARP1 and circRNA biogenesis and function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 15:e1823. [PMID: 37957925 PMCID: PMC11089078 DOI: 10.1002/wrna.1823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 11/15/2023]
Abstract
PARP1 (poly-ADP-ribose polymerase 1) is a multidomain protein with a flexible and self-folding structure that allows it to interact with a wide range of biomolecules, including nucleic acids and target proteins. PARP1 interacts with its target molecules either covalently via PARylation or non-covalently through its PAR moieties induced by auto-PARylation. These diverse interactions allow PARP1 to participate in complex regulatory circuits and cellular functions. Although the most studied PARP1-mediated functions are associated with DNA repair and cellular stress response, subsequent discoveries have revealed additional biological functions. Based on these findings, PARP1 is now recognized as a major modulator of gene expression. Several discoveries show that this multifunctional protein has been intimately connected to several steps of mRNA biogenesis, from transcription initiation to mRNA splicing, polyadenylation, export, and translation of mRNA to proteins. Nevertheless, our understanding of PARP1's involvement in the biogenesis of both coding and noncoding RNA, notably circular RNA (circRNA), remains restricted. In this review, we outline the possible roles of PARP1 in circRNA biogenesis. A full examination of the regulatory roles of PARP1 in nuclear processes with an emphasis on circRNA may reveal new avenues to control dysregulation implicated in the pathogenesis of several diseases such as neurodegenerative disorders and cancers. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Hejer Dhahri
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
- Department of Epigenetics, Van Andel Research Institute, Grand Rapids, Michigan, USA
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6
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Zhang Y, Tian L, Lu C. Chloroplast gene expression: Recent advances and perspectives. PLANT COMMUNICATIONS 2023; 4:100611. [PMID: 37147800 PMCID: PMC10504595 DOI: 10.1016/j.xplc.2023.100611] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/11/2023] [Accepted: 05/01/2023] [Indexed: 05/07/2023]
Abstract
Chloroplasts evolved from an ancient cyanobacterial endosymbiont more than 1.5 billion years ago. During subsequent coevolution with the nuclear genome, the chloroplast genome has remained independent, albeit strongly reduced, with its own transcriptional machinery and distinct features, such as chloroplast-specific innovations in gene expression and complicated post-transcriptional processing. Light activates the expression of chloroplast genes via mechanisms that optimize photosynthesis, minimize photodamage, and prioritize energy investments. Over the past few years, studies have moved from describing phases of chloroplast gene expression to exploring the underlying mechanisms. In this review, we focus on recent advances and emerging principles that govern chloroplast gene expression in land plants. We discuss engineering of pentatricopeptide repeat proteins and its biotechnological effects on chloroplast RNA research; new techniques for characterizing the molecular mechanisms of chloroplast gene expression; and important aspects of chloroplast gene expression for improving crop yield and stress tolerance. We also discuss biological and mechanistic questions that remain to be answered in the future.
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Affiliation(s)
- Yi Zhang
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Lin Tian
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China
| | - Congming Lu
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China.
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Zhang Y, Xu ZM, Wang Q, Li QS, Sun XQ, Li JT. The Promoter SNPs Were Associated with Both the Contents of Poly-Unsaturated Fatty Acids (PUFAs) and the Expressions of PUFA-Related Genes in Common Carp. BIOLOGY 2023; 12:biology12040524. [PMID: 37106724 PMCID: PMC10135829 DOI: 10.3390/biology12040524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/18/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The allo-tetraploid common carp encodes two duplicated fads2 genes (fads2a and fads2b) and two duplicated elovl5 genes (elovl5a and elovl5b). The coding SNPs (cSNPs) of these genes were reported to be significantly associated with the PUFA contents. Whether the promoter SNPs (pSNPs) were associated with the PUFA contents has not been reported yet. In this study, after sequencing the promoters of these four genes, we identified six pSNPs associated with the contents of PUFAs in common carp, including one elovl5a pSNP, one elovl5b pSNP, and four fads2b pSNPs. The pSNPs were predicted in the locations of transcriptional factor binding sites. Together with previously identified cSNPs in fads2b and elovl5b, the pSNPs and cSNPs of these two genes had the joint effects on the PUFA contents with higher explained percentage of phenotypic variation of the PUFA contents than single gene. The expression levels of both fads2a and fads2b were significantly positively correlated with the contents of six PUFAs. The fads2b pSNPs corresponding to higher fads2b expression levels were associated with higher PUFA contents. The pSNPs and cSNPs will be useful for the future selection breeding of common carp with higher PUFA contents.
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8
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Akcan TS, Vilov S, Heinig M. Predictive model of transcriptional elongation control identifies trans regulatory factors from chromatin signatures. Nucleic Acids Res 2023; 51:1608-1624. [PMID: 36727445 PMCID: PMC9976927 DOI: 10.1093/nar/gkac1272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/09/2022] [Accepted: 01/12/2023] [Indexed: 02/03/2023] Open
Abstract
Promoter-proximal Polymerase II (Pol II) pausing is a key rate-limiting step for gene expression. DNA and RNA-binding trans-acting factors regulating the extent of pausing have been identified. However, we lack a quantitative model of how interactions of these factors determine pausing, therefore the relative importance of implicated factors is unknown. Moreover, previously unknown regulators might exist. Here we address this gap with a machine learning model that accurately predicts the extent of promoter-proximal Pol II pausing from large-scale genome and transcriptome binding maps and gene annotation and sequence composition features. We demonstrate high accuracy and generalizability of the model by validation on an independent cell line which reveals the model's cell line agnostic character. Model interpretation in light of prior knowledge about molecular functions of regulatory factors confirms the interconnection of pausing with other RNA processing steps. Harnessing underlying feature contributions, we assess the relative importance of each factor, quantify their predictive effects and systematically identify previously unknown regulators of pausing. We additionally identify 16 previously unknown 7SK ncRNA interacting RNA-binding proteins predictive of pausing. Our work provides a framework to further our understanding of the regulation of the critical early steps in transcriptional elongation.
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Affiliation(s)
- Toray S Akcan
- Institute of Computational Biology, Helmholtz Zentrum München Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.,Department of Computer Science, TUM School of Computation, Information and Technology, Technical University Munich, Munich, Germany
| | - Sergey Vilov
- Institute of Computational Biology, Helmholtz Zentrum München Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Matthias Heinig
- Institute of Computational Biology, Helmholtz Zentrum München Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.,Department of Computer Science, TUM School of Computation, Information and Technology, Technical University Munich, Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Munich Heart Association, Partner Site Munich, 10785 Berlin, Germany
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9
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He PC, Wei J, Dou X, Harada BT, Zhang Z, Ge R, Liu C, Zhang LS, Yu X, Wang S, Lyu R, Zou Z, Chen M, He C. Exon architecture controls mRNA m 6A suppression and gene expression. Science 2023; 379:677-682. [PMID: 36705538 PMCID: PMC9990141 DOI: 10.1126/science.abj9090] [Citation(s) in RCA: 67] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 01/16/2023] [Indexed: 01/28/2023]
Abstract
N6-methyladenosine (m6A) is the most abundant messenger RNA (mRNA) modification and plays crucial roles in diverse physiological processes. Using a massively parallel assay for m6A (MPm6A), we discover that m6A specificity is globally regulated by suppressors that prevent m6A deposition in unmethylated transcriptome regions. We identify exon junction complexes (EJCs) as m6A suppressors that protect exon junction-proximal RNA within coding sequences from methylation and regulate mRNA stability through m6A suppression. EJC suppression of m6A underlies multiple global characteristics of mRNA m6A specificity, with the local range of EJC protection sufficient to suppress m6A deposition in average-length internal exons but not in long internal and terminal exons. EJC-suppressed methylation sites colocalize with EJC-suppressed splice sites, which suggests that exon architecture broadly determines local mRNA accessibility to regulatory complexes.
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Affiliation(s)
- P. Cody He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Jiangbo Wei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoyang Dou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Bryan T. Harada
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zijie Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
- State Key Laboratory for Conservation and Utilization of Bio-Resources, School of Life Sciences, Yunnan University, Kunming, Yunnan 650091, China
| | - Ruiqi Ge
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Chang Liu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Li-Sheng Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Xianbin Yu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Shuai Wang
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Ruitu Lyu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zhongyu Zou
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Mengjie Chen
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
- Section of Genetic Medicine, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
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10
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Li D, Yang J, Malik V, Huang Y, Huang X, Zhou H, Wang J. An RNAi screen of RNA helicases identifies eIF4A3 as a regulator of embryonic stem cell identity. Nucleic Acids Res 2022; 50:12462-12479. [PMID: 36416264 PMCID: PMC9757061 DOI: 10.1093/nar/gkac1084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 11/24/2022] Open
Abstract
RNA helicases are involved in multiple steps of RNA metabolism to direct their roles in gene expression, yet their functions in pluripotency control remain largely unexplored. Starting from an RNA interference (RNAi) screen of RNA helicases, we identified that eIF4A3, a DEAD-box (Ddx) helicase component of the exon junction complex (EJC), is essential for the maintenance of embryonic stem cells (ESCs). Mechanistically, we show that eIF4A3 post-transcriptionally controls the pluripotency-related cell cycle regulators and that its depletion causes the loss of pluripotency via cell cycle dysregulation. Specifically, eIF4A3 is required for the efficient nuclear export of Ccnb1 mRNA, which encodes Cyclin B1, a key component of the pluripotency-promoting pathway during the cell cycle progression of ESCs. Our results reveal a previously unappreciated role for eIF4A3 and its associated EJC in maintaining stem cell pluripotency through post-transcriptional control of the cell cycle.
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Affiliation(s)
- Dan Li
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Cell, Developmental and Regenerative Biology; The Black Family Stem Cell Institute; Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jihong Yang
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Vikas Malik
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Yuting Huang
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Xin Huang
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Hongwei Zhou
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jianlong Wang
- Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia Stem Cell Initiative, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
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11
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Schwarz JD, Lukassen S, Bhandare P, Eing L, Snaebjörnsson MT, García YC, Kisker JP, Schulze A, Wolf E. The glycolytic enzyme ALDOA and the exon junction complex protein RBM8A are regulators of ribosomal biogenesis. Front Cell Dev Biol 2022; 10:954358. [PMID: 36187487 PMCID: PMC9515781 DOI: 10.3389/fcell.2022.954358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/19/2022] [Indexed: 11/25/2022] Open
Abstract
Cellular growth is a fundamental process of life and must be precisely controlled in multicellular organisms. Growth is crucially controlled by the number of functional ribosomes available in cells. The production of new ribosomes depends critically on the activity of RNA polymerase (RNAP) II in addition to the activity of RNAP I and III, which produce ribosomal RNAs. Indeed, the expression of both, ribosomal proteins and proteins required for ribosome assembly (ribosomal biogenesis factors), is considered rate-limiting for ribosome synthesis. Here, we used genetic screening to identify novel transcriptional regulators of cell growth genes by fusing promoters from a ribosomal protein gene (Rpl18) and from a ribosomal biogenesis factor (Fbl) with fluorescent protein genes (RFP, GFP) as reporters. Subsequently, both reporters were stably integrated into immortalized mouse fibroblasts, which were then transduced with a genome-wide sgRNA-CRISPR knockout library. Subsequently, cells with altered reporter activity were isolated by FACS and the causative sgRNAs were identified. Interestingly, we identified two novel regulators of growth genes. Firstly, the exon junction complex protein RBM8A controls transcript levels of the intronless reporters used here. By acute depletion of RBM8A protein using the auxin degron system combined with the genome-wide analysis of nascent transcription, we showed that RBM8A is an important global regulator of ribosomal protein transcripts. Secondly, we unexpectedly observed that the glycolytic enzyme aldolase A (ALDOA) regulates the expression of ribosomal biogenesis factors. Consistent with published observations that a fraction of this protein is located in the nucleus, this may be a mechanism linking transcription of growth genes to metabolic processes and possibly to metabolite availability.
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Affiliation(s)
- Jessica Denise Schwarz
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - Sören Lukassen
- Center for Digital Health, Berlin Institute of Health at Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Pranjali Bhandare
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - Lorenz Eing
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | | | - Yiliam Cruz García
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - Jan Philipp Kisker
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - Almut Schulze
- Tumor Metabolism and Microenvironment, German Cancer Research Center, Heidelberg, Germany
| | - Elmar Wolf
- Cancer Systems Biology Group, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
- *Correspondence: Elmar Wolf,
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12
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Abstract
RNA modifications are prevalent among all the classes of RNA, regulate diverse biological processes, and have emerged as a key regulatory mechanism in post-transcriptional control of gene expression. They are subjected to precise spatial and temporal control and shown to be critical for the maintenance of normal development and physiology. For example, m6A modification of mRNA affects stability, recruitment of RNA binding protein (RBP), translation, and splicing. The deposition of m6A on the RNA happens co-transcriptionally, allowing the tight coupling between the transcription and RNA modification machinery. The m6A modification is affected by transcriptional dynamics, but recent insights also suggest that m6A machinery impacts transcription and chromatin signature.
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Affiliation(s)
- Junaid Akhtar
- Institute of Developmental Biology and Neurobiology, University of Mainz, Mainz, Germany
| | - Margot Lugoboni
- Department reproduction and development in health and disease, Université Clermont Auvergne, CNRS UMR6293, INSERM U1103, Genetics, Reproduction and Development Institute (IGReD), Clermont-Ferrand, France
| | - Guillaume Junion
- Department reproduction and development in health and disease, Université Clermont Auvergne, CNRS UMR6293, INSERM U1103, Genetics, Reproduction and Development Institute (IGReD), Clermont-Ferrand, France
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13
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Mines RC, Lipniacki T, Shen X. Slow nucleosome dynamics set the transcriptional speed limit and induce RNA polymerase II traffic jams and bursts. PLoS Comput Biol 2022; 18:e1009811. [PMID: 35143483 PMCID: PMC8865691 DOI: 10.1371/journal.pcbi.1009811] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 02/23/2022] [Accepted: 01/06/2022] [Indexed: 11/19/2022] Open
Abstract
Nucleosomes are recognized as key regulators of transcription. However, the relationship between slow nucleosome unwrapping dynamics and bulk transcriptional properties has not been thoroughly explored. Here, an agent-based model that we call the dynamic defect Totally Asymmetric Simple Exclusion Process (ddTASEP) was constructed to investigate the effects of nucleosome-induced pausing on transcriptional dynamics. Pausing due to slow nucleosome dynamics induced RNAPII convoy formation, which would cooperatively prevent nucleosome rebinding leading to bursts of transcription. The mean first passage time (MFPT) and the variance of first passage time (VFPT) were analytically expressed in terms of the nucleosome rate constants, allowing for the direct quantification of the effects of nucleosome-induced pausing on pioneering polymerase dynamics. The mean first passage elongation rate γ(hc, ho) is inversely proportional to the MFPT and can be considered to be a new axis of the ddTASEP phase diagram, orthogonal to the classical αβ-plane (where α and β are the initiation and termination rates). Subsequently, we showed that, for β = 1, there is a novel jamming transition in the αγ-plane that separates the ddTASEP dynamics into initiation-limited and nucleosome pausing-limited regions. We propose analytical estimates for the RNAPII density ρ, average elongation rate v, and transcription flux J and verified them numerically. We demonstrate that the intra-burst RNAPII waiting times tin follow the time-headway distribution of a max flux TASEP and that the average inter-burst interval tIBI¯ correlates with the index of dispersion De. In the limit γ→0, the average burst size reaches a maximum set by the closing rate hc. When α≪1, the burst sizes are geometrically distributed, allowing large bursts even while the average burst size NB¯ is small. Last, preliminary results on the relative effects of static and dynamic defects are presented to show that dynamic defects can induce equal or greater pausing than static bottle necks. To perform specific functions, cells must express specific genes by copying the information in DNA into RNA via transcription. Structural proteins called nucleosomes are spaced every 200 base pairs along the length of a strand of DNA and play a crucial function in the regulation of gene activity by tightly binding DNA strands and condensing them into heterochromatin, preventing transcription by RNA polymerase II (RNAPII). Even on active genes where nucleosomes are loosely attached to DNA strands, the wrapping and unwrapping of nucleosomes pause transcription as RNAPII passes by. Previous mathematical models of transcription have compared this biological process to traffic on a one lane highway without obstructions. In contrast, our proposed model simulates transcription like traffic in a grid system where nucleosomes can be thought of as pedestrians or other vehicles crossing the road at regularly spaced intersections. Just as side street traffic and pedestrian crossings can cause cars to form convoys and cause jams limiting the max speed in an area, nucleosomes can cause RNAPII to form convoys that lead to bursts of mRNA production and limit the average polymerase flux through the gene.
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Affiliation(s)
- Robert C. Mines
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Tomasz Lipniacki
- Department of Biosystems and Soft Matter, Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
- * E-mail: (TL); (XS)
| | - Xiling Shen
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
- Woo Center for Big Data and Precision Health, Duke University, Durham, North Carolina, United States of America
- * E-mail: (TL); (XS)
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14
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Prudêncio P, Savisaar R, Rebelo K, Martinho RG, Carmo-Fonseca M. Transcription and splicing dynamics during early Drosophila development. RNA (NEW YORK, N.Y.) 2022; 28:139-161. [PMID: 34667107 PMCID: PMC8906543 DOI: 10.1261/rna.078933.121] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/23/2021] [Indexed: 05/03/2023]
Abstract
Widespread cotranscriptional splicing has been demonstrated from yeast to human. However, most studies to date addressing the kinetics of splicing relative to transcription used either Saccharomyces cerevisiae or metazoan cultured cell lines. Here, we adapted native elongating transcript sequencing technology (NET-seq) to measure cotranscriptional splicing dynamics during the early developmental stages of Drosophila melanogaster embryos. Our results reveal the position of RNA polymerase II (Pol II) when both canonical and recursive splicing occur. We found heterogeneity in splicing dynamics, with some RNAs spliced immediately after intron transcription, whereas for other transcripts no splicing was observed over the first 100 nt of the downstream exon. Introns that show splicing completion before Pol II has reached the end of the downstream exon are necessarily intron-defined. We studied the splicing dynamics of both nascent pre-mRNAs transcribed in the early embryo, which have few and short introns, as well as pre-mRNAs transcribed later in embryonic development, which contain multiple long introns. As expected, we found a relationship between the proportion of spliced reads and intron size. However, intron definition was observed at all intron sizes. We further observed that genes transcribed in the early embryo tend to be isolated in the genome whereas genes transcribed later are often overlapped by a neighboring convergent gene. In isolated genes, transcription termination occurred soon after the polyadenylation site, while in overlapped genes, Pol II persisted associated with the DNA template after cleavage and polyadenylation of the nascent transcript. Taken together, our data unravel novel dynamic features of Pol II transcription and splicing in the developing Drosophila embryo.
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Affiliation(s)
- Pedro Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
- Algarve Biomedical Center Research Institute (ABC-RI), Universidade do Algarve, 8005-139 Faro, Portugal
| | - Rosina Savisaar
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Kenny Rebelo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Rui Gonçalo Martinho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
- Algarve Biomedical Center Research Institute (ABC-RI), Universidade do Algarve, 8005-139 Faro, Portugal
- Department of Medical Sciences and Institute for Biomedicine (iBiMED), Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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15
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Joseph B, Scala C, Kondo S, Lai EC. Molecular and genetic dissection of recursive splicing. Life Sci Alliance 2021; 5:5/1/e202101063. [PMID: 34759052 PMCID: PMC8605326 DOI: 10.26508/lsa.202101063] [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: 02/22/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 11/24/2022] Open
Abstract
Intronic ratchet points (RPs) are abundant within long introns in the Drosophila genome and consist of juxtaposed splice acceptor and splice donor (SD) sites. Although they appear to encompass zero-nucleotide exons, we recently clarified that intronic recursive splicing (RS) requires a cryptic exon at the RP (an RS-exon), which is subsequently always skipped and thus absent from mRNA. In addition, Drosophila encodes a smaller set of expressed exons bearing features of RS. Here, we investigate mechanisms that regulate the choice between RP and RS-exon SDs. First, analysis of Drosophila RP SD mutants demonstrates that SD competition suppresses inclusion of cryptic exons in endogenous contexts. Second, characterization of RS-exon reporters implicates exonic sequences as influencing choice of RS-exon usage. Using RS-exon swap and mutagenesis assays, we show exonic sequences can determine RS-exon inclusion. Finally, we provide evidence that splicing can suppress utilization of RP SDs to enable RS-exon expression. Overall, multiple factors can influence splicing of Drosophila RS-exons, which usually result in their complete suppression as zero-nucleotide RPs, but occasionally yield translated RS-exons.
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Affiliation(s)
- Brian Joseph
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA .,Louis V Gerstner, Jr Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Chaz Scala
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Shu Kondo
- Research Building 11F, Tokyo University of Science, Tokyo, Japan
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
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16
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m 6A RNA methylation regulates promoter- proximal pausing of RNA polymerase II. Mol Cell 2021; 81:3356-3367.e6. [PMID: 34297910 DOI: 10.1016/j.molcel.2021.06.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 03/04/2021] [Accepted: 06/18/2021] [Indexed: 12/20/2022]
Abstract
RNA polymerase II (RNAP II) pausing is essential to precisely control gene expression and is critical for development of metazoans. Here, we show that the m6A RNA modification regulates promoter-proximal RNAP II pausing in Drosophila cells. The m6A methyltransferase complex (MTC) and the nuclear reader Ythdc1 are recruited to gene promoters. Depleting the m6A MTC leads to a decrease in RNAP II pause release and in Ser2P occupancy on the gene body and affects nascent RNA transcription. Tethering Mettl3 to a heterologous gene promoter is sufficient to increase RNAP II pause release, an effect that relies on its m6A catalytic domain. Collectively, our data reveal an important link between RNAP II pausing and the m6A RNA modification, thus adding another layer to m6A-mediated gene regulation.
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17
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Muniz L, Nicolas E, Trouche D. RNA polymerase II speed: a key player in controlling and adapting transcriptome composition. EMBO J 2021; 40:e105740. [PMID: 34254686 PMCID: PMC8327950 DOI: 10.15252/embj.2020105740] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 05/01/2021] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
RNA polymerase II (RNA Pol II) speed or elongation rate, i.e., the number of nucleotides synthesized per unit of time, is a major determinant of transcriptome composition. It controls co‐transcriptional processes such as splicing, polyadenylation, and transcription termination, thus regulating the production of alternative splice variants, circular RNAs, alternatively polyadenylated transcripts, or read‐through transcripts. RNA Pol II speed itself is regulated in response to intra‐ and extra‐cellular stimuli and can in turn affect the transcriptome composition in response to these stimuli. Evidence points to a potentially important role of transcriptome composition modification through RNA Pol II speed regulation for adaptation of cells to a changing environment, thus pointing to a function of RNA Pol II speed regulation in cellular physiology. Analyzing RNA Pol II speed dynamics may therefore be central to fully understand the regulation of physiological processes, such as the development of multicellular organisms. Recent findings also raise the possibility that RNA Pol II speed deregulation can be detrimental and participate in disease progression. Here, we review initial and current approaches to measure RNA Pol II speed, as well as providing an overview of the factors controlling speed and the co‐transcriptional processes which are affected. Finally, we discuss the role of RNA Pol II speed regulation in cell physiology.
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Affiliation(s)
- Lisa Muniz
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Estelle Nicolas
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Didier Trouche
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
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18
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Roos D, de Boer M. Mutations in cis that affect mRNA synthesis, processing and translation. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166166. [PMID: 33971252 DOI: 10.1016/j.bbadis.2021.166166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
Genetic mutations that cause hereditary diseases usually affect the composition of the transcribed mRNA and its encoded protein, leading to instability of the mRNA and/or the protein. Sometimes, however, such mutations affect the synthesis, the processing or the translation of the mRNA, with similar disastrous effects. We here present an overview of mRNA synthesis, its posttranscriptional modification and its translation into protein. We then indicate which elements in these processes are known to be affected by pathogenic mutations, but we restrict our review to mutations in cis, in the DNA of the gene that encodes the affected protein. These mutations can be in enhancer or promoter regions of the gene, which act as binding sites for transcription factors involved in pre-mRNA synthesis. We also describe mutations in polyadenylation sequences and in splice site regions, exonic and intronic, involved in intron removal. Finally, we include mutations in the Kozak sequence in mRNA, which is involved in protein synthesis. We provide examples of genetic diseases caused by mutations in these DNA regions and refer to databases to help identify these regions. The over-all knowledge of mRNA synthesis, processing and translation is essential for improvement of the diagnosis of patients with genetic diseases.
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Affiliation(s)
- Dirk Roos
- Sanquin Blood Supply Organization, Dept. of Blood Cell Research, Landsteiner Laboratory, Amsterdam University Medical Centre, location AMC, University of Amsterdam, Amsterdam, the Netherlands.
| | - Martin de Boer
- Sanquin Blood Supply Organization, Dept. of Blood Cell Research, Landsteiner Laboratory, Amsterdam University Medical Centre, location AMC, University of Amsterdam, Amsterdam, the Netherlands
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19
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Joseph B, Lai EC. The Exon Junction Complex and intron removal prevent re-splicing of mRNA. PLoS Genet 2021; 17:e1009563. [PMID: 34033644 PMCID: PMC8184009 DOI: 10.1371/journal.pgen.1009563] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 06/07/2021] [Accepted: 04/26/2021] [Indexed: 01/23/2023] Open
Abstract
Accurate splice site selection is critical for fruitful gene expression. Recently, the mammalian EJC was shown to repress competing, cryptic, splice sites (SS). However, the evolutionary generality of this remains unclear. Here, we demonstrate the Drosophila EJC suppresses hundreds of functional cryptic SS, even though most bear weak splicing motifs and are seemingly incompetent. Mechanistically, the EJC directly conceals cryptic splicing elements by virtue of its position-specific recruitment, preventing aberrant SS definition. Unexpectedly, we discover the EJC inhibits scores of regenerated 5' and 3' recursive SS on segments that have already undergone splicing, and that loss of EJC regulation triggers faulty resplicing of mRNA. An important corollary is that certain intronless cDNA constructs yield unanticipated, truncated transcripts generated by resplicing. We conclude the EJC has conserved roles to defend transcriptome fidelity by (1) repressing illegitimate splice sites on pre-mRNAs, and (2) preventing inadvertent activation of such sites on spliced segments.
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Affiliation(s)
- Brian Joseph
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
- Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Eric C. Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
- Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
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20
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Willbanks A, Wood S, Cheng JX. RNA Epigenetics: Fine-Tuning Chromatin Plasticity and Transcriptional Regulation, and the Implications in Human Diseases. Genes (Basel) 2021; 12:genes12050627. [PMID: 33922187 PMCID: PMC8145807 DOI: 10.3390/genes12050627] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/13/2021] [Accepted: 04/14/2021] [Indexed: 02/08/2023] Open
Abstract
Chromatin structure plays an essential role in eukaryotic gene expression and cell identity. Traditionally, DNA and histone modifications have been the focus of chromatin regulation; however, recent molecular and imaging studies have revealed an intimate connection between RNA epigenetics and chromatin structure. Accumulating evidence suggests that RNA serves as the interplay between chromatin and the transcription and splicing machineries within the cell. Additionally, epigenetic modifications of nascent RNAs fine-tune these interactions to regulate gene expression at the co- and post-transcriptional levels in normal cell development and human diseases. This review will provide an overview of recent advances in the emerging field of RNA epigenetics, specifically the role of RNA modifications and RNA modifying proteins in chromatin remodeling, transcription activation and RNA processing, as well as translational implications in human diseases.
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21
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Gehring NH, Roignant JY. Anything but Ordinary – Emerging Splicing Mechanisms in Eukaryotic Gene Regulation. Trends Genet 2021; 37:355-372. [DOI: 10.1016/j.tig.2020.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022]
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22
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Caizzi L, Monteiro-Martins S, Schwalb B, Lysakovskaia K, Schmitzova J, Sawicka A, Chen Y, Lidschreiber M, Cramer P. Efficient RNA polymerase II pause release requires U2 snRNP function. Mol Cell 2021; 81:1920-1934.e9. [PMID: 33689748 DOI: 10.1016/j.molcel.2021.02.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 01/07/2021] [Accepted: 02/10/2021] [Indexed: 12/21/2022]
Abstract
Transcription by RNA polymerase II (Pol II) is coupled to pre-mRNA splicing, but the underlying mechanisms remain poorly understood. Co-transcriptional splicing requires assembly of a functional spliceosome on nascent pre-mRNA, but whether and how this influences Pol II transcription remains unclear. Here we show that inhibition of pre-mRNA branch site recognition by the spliceosome component U2 snRNP leads to a widespread and strong decrease in new RNA synthesis from human genes. Multiomics analysis reveals that inhibition of U2 snRNP function increases the duration of Pol II pausing in the promoter-proximal region, impairs recruitment of the pause release factor P-TEFb, and reduces Pol II elongation velocity at the beginning of genes. Our results indicate that efficient release of paused Pol II into active transcription elongation requires the formation of functional spliceosomes and that eukaryotic mRNA biogenesis relies on positive feedback from the splicing machinery to the transcription machinery.
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Affiliation(s)
- Livia Caizzi
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sara Monteiro-Martins
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kseniia Lysakovskaia
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jana Schmitzova
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Anna Sawicka
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ying Chen
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Michael Lidschreiber
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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23
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Eleazer R, Fondufe‐Mittendorf YN. The multifaceted role of PARP1 in RNA biogenesis. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1617. [PMID: 32656996 PMCID: PMC7856298 DOI: 10.1002/wrna.1617] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/11/2020] [Accepted: 06/17/2020] [Indexed: 12/31/2022]
Abstract
Poly(ADP-ribose) polymerases (PARPs) are abundant nuclear proteins that synthesize ADP ribose polymers (pADPr) and catalyze the addition of (p)ADPr to target biomolecules. PARP1, the most abundant and well-studied PARP, is a multifunctional enzyme that participates in numerous critical cellular processes. A considerable amount of PARP research has focused on PARP1's role in DNA damage. However, an increasing body of evidence outlines more routine roles for PARP and PARylation in nearly every step of RNA biogenesis and metabolism. PARP1's involvement in these RNA processes is pleiotropic and has been ascribed to PARP1's unique flexible domain structures. PARP1 domains are modular self-arranged enabling it to recognize structurally diverse substrates and to act simultaneously through multiple discrete mechanisms. These mechanisms include direct PARP1-protein binding, PARP1-nucleic acid binding, covalent PARylation of target molecules, covalent autoPARylation, and induction of noncovalent interactions with PAR molecules. A combination of these mechanisms has been implicated in PARP1's context-specific regulation of RNA biogenesis and metabolism. We examine the mechanisms of PARP1 regulation in transcription initiation, elongation and termination, co-transcriptional splicing, RNA export, and post-transcriptional RNA processing. Finally, we consider promising new investigative avenues for PARP1 involvement in these processes with an emphasis on PARP1 regulation of subcellular condensates. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Rebekah Eleazer
- Department of Molecular and Cellular Biochemistry and Markey Cancer CenterUniversity of KentuckyLexingtonKentuckyUSA
| | - Yvonne N. Fondufe‐Mittendorf
- Department of Molecular and Cellular Biochemistry and Markey Cancer CenterUniversity of KentuckyLexingtonKentuckyUSA
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24
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Dollinger R, Gilmour DS. Regulation of Promoter Proximal Pausing of RNA Polymerase II in Metazoans. J Mol Biol 2021; 433:166897. [PMID: 33640324 DOI: 10.1016/j.jmb.2021.166897] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
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Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 462 North Frear, University Park, PA 16802, USA.
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 465A North Frear, University Park, PA 16802, USA.
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25
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Tellier M, Maudlin I, Murphy S. Transcription and splicing: A two-way street. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1593. [PMID: 32128990 DOI: 10.1002/wrna.1593] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/18/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
RNA synthesis by RNA polymerase II and RNA processing are closely coupled during the transcription cycle of protein-coding genes. This coupling affords opportunities for quality control and regulation of gene expression and the effects can go in both directions. For example, polymerase speed can affect splice site selection and splicing can increase transcription and affect the chromatin landscape. Here we review the many ways that transcription and splicing influence one another, including how splicing "talks back" to transcription. We will also place the connections between transcription and splicing in the context of other RNA processing events that define the exons that will make up the final mRNA. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Isabella Maudlin
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Shona Murphy
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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26
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A Day in the Life of the Exon Junction Complex. Biomolecules 2020; 10:biom10060866. [PMID: 32517083 PMCID: PMC7355637 DOI: 10.3390/biom10060866] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022] Open
Abstract
The exon junction complex (EJC) is an abundant messenger ribonucleoprotein (mRNP) component that is assembled during splicing and binds to mRNAs upstream of exon-exon junctions. EJCs accompany the mRNA during its entire life in the nucleus and the cytoplasm and communicate the information about the splicing process and the position of introns. Specifically, the EJC’s core components and its associated proteins regulate different steps of gene expression, including pre-mRNA splicing, mRNA export, translation, and nonsense-mediated mRNA decay (NMD). This review summarizes the most important functions and main protagonists in the life of the EJC. It also provides an overview of the latest findings on the assembly, composition and molecular activities of the EJC and presents them in the chronological order, in which they play a role in the EJC’s life cycle.
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27
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Fiszbein A, Krick KS, Begg BE, Burge CB. Exon-Mediated Activation of Transcription Starts. Cell 2019; 179:1551-1565.e17. [PMID: 31787377 DOI: 10.1016/j.cell.2019.11.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/20/2019] [Accepted: 10/30/2019] [Indexed: 10/25/2022]
Abstract
The processing of RNA transcripts from mammalian genes occurs in proximity to their transcription. Here, we describe a phenomenon affecting thousands of genes that we call exon-mediated activation of transcription starts (EMATS), in which the splicing of internal exons impacts promoter choice and the expression level of the gene. We observed that evolutionary gain of internal exons is associated with gain of new transcription start sites (TSSs) nearby and increased gene expression. Inhibiting exon splicing reduced transcription from nearby promoters, and creation of new spliced exons activated transcription from cryptic promoters. The strongest effects occurred for weak promoters located proximal and upstream of efficiently spliced exons. Together, our findings support a model in which splicing recruits transcription machinery locally to influence TSS choice and identify exon gain, loss, and regulatory change as major contributors to the evolution of alternative promoters and gene expression in mammals.
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Affiliation(s)
- Ana Fiszbein
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Keegan S Krick
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Bridget E Begg
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Christopher B Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02138, USA.
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