1
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Palumbo RJ, Yang Y, Feigon J, Hanes SD. Catalytic activity of the Bin3/MePCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. Genetics 2024; 226:iyad203. [PMID: 37982586 PMCID: PMC10763541 DOI: 10.1093/genetics/iyad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/27/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
Methylphosphate Capping Enzyme (MePCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MePCE in vitro, little is known about its functions in vivo, or what roles-if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MePCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MePCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MePCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Yuan Yang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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2
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Pal S, Biswas D. Promoter-proximal regulation of gene transcription: Key factors involved and emerging role of general transcription factors in assisting productive elongation. Gene 2023:147571. [PMID: 37331491 DOI: 10.1016/j.gene.2023.147571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
The pausing of RNA polymerase II (Pol II) at the promoter-proximal sites is a key rate-limiting step in gene expression. Cells have dedicated a specific set of proteins that sequentially establish pause and then release the Pol II from promoter-proximal sites. A well-controlled pausing and subsequent release of Pol II is crucial for thefine tuning of expression of genes including signal-responsive and developmentally-regulated ones. The release of paused Pol II broadly involves its transition from initiation to elongation. In this review article, we will discuss the phenomenon of Pol II pausing, the underlying mechanism, and also the role of different known factors, with an emphasis on general transcription factors, involved in this overall regulation. We will further discuss some recent findings suggesting a possible role (underexplored) of initiation factors in assisting the transition of transcriptionally-engaged paused Pol II into productive elongation.
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Affiliation(s)
- Sujay Pal
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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3
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Palumbo RJ, Hanes SD. Catalytic activity of the Bin3/MEPCE methyltransferase domain is dispensable for 7SK snRNP function in Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.01.543302. [PMID: 37333392 PMCID: PMC10274667 DOI: 10.1101/2023.06.01.543302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methylphosphate Capping Enzyme (MEPCE) monomethylates the gamma phosphate at the 5' end of the 7SK noncoding RNA, a modification thought to protect 7SK from degradation. 7SK serves as a scaffold for assembly of a snRNP complex that inhibits transcription by sequestering the positive elongation factor P-TEFb. While much is known about the biochemical activity of MEPCE in vitro, little is known about its functions in vivo, or what roles- if any-there are for regions outside the conserved methyltransferase domain. Here, we investigated the role of Bin3, the Drosophila ortholog of MEPCE, and its conserved functional domains in Drosophila development. We found that bin3 mutant females had strongly reduced rates of egg-laying, which was rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 promotes fecundity by repressing P-TEFb. bin3 mutants also exhibited neuromuscular defects, analogous to a patient with MEPCE haploinsufficiency. These defects were also rescued by genetic reduction of P-TEFb activity, suggesting that Bin3 and MEPCE have conserved roles in promoting neuromuscular function by repressing P-TEFb. Unexpectedly, we found that a Bin3 catalytic mutant (Bin3Y795A) could still bind and stabilize 7SK and rescue all bin3 mutant phenotypes, indicating that Bin3 catalytic activity is dispensable for 7SK stability and snRNP function in vivo. Finally, we identified a metazoan-specific motif (MSM) outside of the methyltransferase domain and generated mutant flies lacking this motif (Bin3ΔMSM). Bin3ΔMSM mutant flies exhibited some-but not all-bin3 mutant phenotypes, suggesting that the MSM is required for a 7SK-independent, tissue-specific function of Bin3.
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Affiliation(s)
- Ryan J Palumbo
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
| | - Steven D Hanes
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University 750 East Adams Street, 4283 Weiskotten Hall, Syracuse, New York, 13210
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4
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Abuhashem A, Chivu AG, Zhao Y, Rice EJ, Siepel A, Danko CG, Hadjantonakis AK. RNA Pol II pausing facilitates phased pluripotency transitions by buffering transcription. Genes Dev 2022; 36:gad.349565.122. [PMID: 35981753 PMCID: PMC9480856 DOI: 10.1101/gad.349565.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/18/2022] [Indexed: 01/03/2023]
Abstract
Promoter-proximal RNA Pol II pausing is a critical step in transcriptional control. Pol II pausing has been predominantly studied in tissue culture systems. While Pol II pausing has been shown to be required for mammalian development, the phenotypic and mechanistic details of this requirement are unknown. Here, we found that loss of Pol II pausing stalls pluripotent state transitions within the epiblast of the early mouse embryo. Using Nelfb -/- mice and a NELFB degron mouse pluripotent stem cell model, we show that embryonic stem cells (ESCs) representing the naïve state of pluripotency successfully initiate a transition program but fail to balance levels of induced and repressed genes and enhancers in the absence of NELF. We found an increase in chromatin-associated NELF during transition from the naïve to later pluripotent states. Overall, our work defines the acute and long-term molecular consequences of NELF loss and reveals a role for Pol II pausing in the pluripotency continuum as a modulator of cell state transitions.
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Affiliation(s)
- Abderhman Abuhashem
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, New York 10065, USA
- Biochemistry Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA
| | - Alexandra G Chivu
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Yixin Zhao
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Edward J Rice
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Charles G Danko
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Biochemistry Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York 10065, USA
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5
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Abuhashem A, Garg V, Hadjantonakis AK. RNA polymerase II pausing in development: orchestrating transcription. Open Biol 2022; 12:210220. [PMID: 34982944 PMCID: PMC8727152 DOI: 10.1098/rsob.210220] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The coordinated regulation of transcriptional networks underpins cellular identity and developmental progression. RNA polymerase II promoter-proximal pausing (Pol II pausing) is a prevalent mechanism by which cells can control and synchronize transcription. Pol II pausing regulates the productive elongation step of transcription at key genes downstream of a variety of signalling pathways, such as FGF and Nodal. Recent advances in our understanding of the Pol II pausing machinery and its role in transcription call for an assessment of these findings within the context of development. In this review, we discuss our current understanding of the molecular basis of Pol II pausing and its function during organismal development. By critically assessing the tools used to study this process we conclude that combining recently developed genomics approaches with refined perturbation systems has the potential to expand our understanding of Pol II pausing mechanistically and functionally in the context of development and beyond.
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Affiliation(s)
- Abderhman Abuhashem
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
| | - Vidur Garg
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
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6
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Ngian Z, Lin W, Ong C. NELF-A controls Drosophila healthspan by regulating heat-shock protein-mediated cellular protection and heterochromatin maintenance. Aging Cell 2021; 20:e13348. [PMID: 33788376 PMCID: PMC8135010 DOI: 10.1111/acel.13348] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022] Open
Abstract
NELF‐mediated pausing of RNA polymerase II (RNAPII) constitutes a crucial step in transcription regulation. However, it remains unclear how control release of RNAPII pausing can affect the epigenome and regulate important aspects of animal physiology like aging. We found that NELF‐A dosage regulates Drosophila healthspan: Halving NELF‐A level in the heterozygous mutants or via neuronal‐specific RNAi depletion improves their locomotor activity, stress resistance, and lifespan significantly. Conversely, NELF‐A overexpression shortens fly lifespan drastically. Mechanistically, lowering NELF‐A level facilitates the release of paused RNAPII for productive transcription of the heat‐shock protein (Hsp) genes. The elevated HSPs expression in turn attenuates the accumulation of insoluble protein aggregates, reactive oxidative species, DNA damage and systemic inflammation in the brains of aging NELF‐A depleted flies as compared to their control siblings. This pro‐longevity effect is unique to NELF‐A due to its higher expression level and more efficient pausing of RNAPII than other NELF subunits. Importantly, enhanced resistance to oxidative stress in NELF‐A heterozygous mutants is highly conserved such that knocking down its level in human SH‐SY5Y cells attenuates hydrogen peroxide‐induced DNA damage and apoptosis. Depleting NELF‐A reconfigures the epigenome through the maintenance of H3K9me2‐enriched heterochromatin during aging, leading to the repression of specific retrotransposons like Gypsy‐1 in the brains of NELF‐A mutants. Taken together, we showed that the dosage of neuronal NELF‐A affects multiple aspects of aging in Drosophila by regulating transcription of Hsp genes in the brains, suggesting that targeting transcription elongation might be a viable therapeutic strategy against age‐onset diseases like neurodegeneration.
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Affiliation(s)
- Zhen‐Kai Ngian
- Temasek Life Sciences Laboratory National University of Singapore Singapore Singapore
- Department of Biological Sciences National University of Singapore Singapore Singapore
| | - Wei‐Qi Lin
- Temasek Life Sciences Laboratory National University of Singapore Singapore Singapore
| | - Chin‐Tong Ong
- Temasek Life Sciences Laboratory National University of Singapore Singapore Singapore
- Department of Biological Sciences National University of Singapore Singapore Singapore
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7
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Bordet G, Lodhi N, Guo D, Kossenkov A, Tulin AV. Poly(ADP-ribose) polymerase 1 in genome-wide expression control in Drosophila. Sci Rep 2020; 10:21151. [PMID: 33273587 PMCID: PMC7712786 DOI: 10.1038/s41598-020-78116-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/20/2020] [Indexed: 11/13/2022] Open
Abstract
Poly(ADP-ribose) polymerase 1 (PARP-1) is a nuclear enzyme involved in DNA repair and transcription regulation, among other processes. Malignant transformations, tumor progression, the onset of some neuropathies and other disorders have been linked to misregulation of PARP-1 activity. Despite intensive studies during the last few decades, the role of PARP-1 in transcription regulation is still not well understood. In this study, a transcriptomic analysis in Drosophila melanogaster third instar larvae was carried out. A total of 602 genes were identified, showing large-scale changes in their expression levels in the absence of PARP-1 in vivo. Among these genes, several functional gene groups were present, including transcription factors and cytochrome family members. The transcription levels of genes from the same functional group were affected by the absence of PARP-1 in a similar manner. In the absence of PARP-1, all misregulated genes coding for transcription factors were downregulated, whereas all genes coding for members of the cytochrome P450 family were upregulated. The cytochrome P450 proteins contain heme as a cofactor and are involved in oxidoreduction. Significant changes were also observed in the expression of several mobile elements in the absence of PARP-1, suggesting that PARP-1 may be involved in regulating the expression of mobile elements.
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Affiliation(s)
- Guillaume Bordet
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Road, Stop 9061, Grand Forks, ND, 58202, USA
| | - Niraj Lodhi
- Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Danping Guo
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Road, Stop 9061, Grand Forks, ND, 58202, USA
| | | | - Alexei V Tulin
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, 501 North Columbia Road, Stop 9061, Grand Forks, ND, 58202, USA.
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8
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Climent-Cantó P, Carbonell A, Tatarski M, Reina O, Bujosa P, Font-Mateu J, Bernués J, Beato M, Azorín F. The embryonic linker histone dBigH1 alters the functional state of active chromatin. Nucleic Acids Res 2020; 48:4147-4160. [PMID: 32103264 PMCID: PMC7192587 DOI: 10.1093/nar/gkaa122] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/30/2020] [Accepted: 02/25/2020] [Indexed: 11/13/2022] Open
Abstract
Linker histones H1 are principal chromatin components, whose contribution to the epigenetic regulation of chromatin structure and function is not fully understood. In metazoa, specific linker histones are expressed in the germline, with female-specific H1s being normally retained in the early-embryo. Embryonic H1s are present while the zygotic genome is transcriptionally silent and they are replaced by somatic variants upon activation, suggesting a contribution to transcriptional silencing. Here we directly address this question by ectopically expressing dBigH1 in Drosophila S2 cells, which lack dBigH1. We show that dBigH1 binds across chromatin, replaces somatic dH1 and reduces nucleosome repeat length (NRL). Concomitantly, dBigH1 expression down-regulates gene expression by impairing RNApol II binding and histone acetylation. These effects depend on the acidic N-terminal ED-domain of dBigH1 since a truncated form lacking this domain binds across chromatin and replaces dH1 like full-length dBigH1, but it does not affect NRL either transcription. In vitro reconstitution experiments using Drosophila preblastodermic embryo extracts corroborate these results. Altogether these results suggest that the negatively charged N-terminal tail of dBigH1 alters the functional state of active chromatin compromising transcription.
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Affiliation(s)
- Paula Climent-Cantó
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Milos Tatarski
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Oscar Reina
- Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Paula Bujosa
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Jofre Font-Mateu
- Centre de Regulació Genòmica (CRG). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Jordi Bernués
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Miguel Beato
- Centre de Regulació Genòmica (CRG). The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, IBMB, CSIC, Baldiri Reixac, 4, 08028 Barcelona, Spain.,Institute for Research in Biomedicine, IRB Barcelona. The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
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9
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Alikunju S, Severinova E, Yang Z, Ivessa A, Sayed D. Acute NelfA knockdown restricts compensatory gene expression and precipitates ventricular dysfunction during cardiac hypertrophy. J Mol Cell Cardiol 2020; 142:93-104. [PMID: 32278832 DOI: 10.1016/j.yjmcc.2020.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/15/2020] [Accepted: 04/06/2020] [Indexed: 11/30/2022]
Abstract
Coordinated functional balance of negative and positive transcription complexes maintain and accommodate gene expression in hearts during quiescent and hypertrophic conditions, respectively. Negative elongation factor (Nelf) complex has been implicated in RNA polymerase II (pol II) pausing, a widespread regulatory transcriptional phenomenon observed across the cardiac genome. Here, we examine the role of NelfA aka, Wolf-Hirschhorn syndrome candidate 2 (Whsc2), a critical component of the negative elongation complex in hearts undergoing pressure-overload induced hypertrophy. Alignment of high-resolution genome-wide occupancy data of NelfA, Pol II, TFIIB and H3k9ac from control and hypertrophied hearts reveal that NelfA associates with active gene promoters. High NelfA occupancy is seen at promoters of essential and cardiac-enriched genes, expressed under both quiescent and hypertrophic conditions. Conversely, de novo NelfA recruitment is observed at inducible gene promoters with pressure overload, accompanied by significant increase in expression of these genes with hypertrophy. Interestingly, change in promoter NelfA levels correlates with the transcript output in hypertrophied hearts compared to Sham, suggesting NelfA might be playing a critical role in the regulation of gene transcription during cardiac hypertrophy. In vivo knockdown of NelfA (siNelfA) in hearts subjected to pressure-overload results in early ventricular dilatation and dysfunction, associated with decrease in expression of inducible and cardiac-enriched genes in siNelfA hypertrophied compared to control hypertrophied hearts. In accordance, in vitro knockdown of NelfA in cardiomyocytes showed no change in promoter pol II, however significant decrease in in-gene and downstream pol II occupancy was observed. These data suggest an inhibited pol II progression in transcribing and inducible genes, which reflects as a decrease in transcript abundance of these genes. These results indicate that promoter NelfA occupancy is essential for pol II -dependent transcription. Therefore, we conclude that NelfA is required for active transcription and gene expression during cardiac hypertrophy.
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Affiliation(s)
- Saleena Alikunju
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, United States of America
| | - Elena Severinova
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, United States of America
| | - Zhi Yang
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, United States of America
| | - Andreas Ivessa
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, United States of America
| | - Danish Sayed
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, United States of America.
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10
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Webber JL, Zhang J, Massey A, Sanchez-Luege N, Rebay I. Collaborative repressive action of the antagonistic ETS transcription factors Pointed and Yan fine-tunes gene expression to confer robustness in Drosophila. Development 2018; 145:dev.165985. [PMID: 29848501 DOI: 10.1242/dev.165985] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/17/2018] [Indexed: 01/29/2023]
Abstract
The acquisition of cellular identity during development depends on precise spatiotemporal regulation of gene expression, with combinatorial interactions between transcription factors, accessory proteins and the basal transcription machinery together translating complex signaling inputs into appropriate gene expression outputs. The opposing repressive and activating inputs of the Drosophila ETS family transcription factors Yan and Pointed orchestrate numerous cell fate transitions downstream of receptor tyrosine kinase signaling, providing one of the premier systems for studying this process. Current models describe the differentiative transition as a switch from Yan-mediated repression to Pointed-mediated activation of common target genes. We describe here a new layer of regulation whereby Yan and Pointed co-occupy regulatory elements to repress gene expression in a coordinated manner, with Pointed being unexpectedly required for the genome-wide occupancy of both Yan and the co-repressor Groucho. Using even skipped as a test-case, synergistic genetic interactions between Pointed, Groucho, Yan and components of the RNA polymerase II pausing machinery suggest that Pointed integrates multiple scales of repressive regulation to confer robustness. We speculate that this mechanism may be used broadly to fine-tune the expression of many genes crucial for development.
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Affiliation(s)
- Jemma L Webber
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Jie Zhang
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Alex Massey
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Nicelio Sanchez-Luege
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Ilaria Rebay
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
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11
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Yu H, You X, Li J, Zhang X, Zhang S, Jiang S, Lin X, Lin HR, Meng Z, Shi Q. A genome-wide association study on growth traits in orange-spotted grouper (Epinephelus coioides) with RAD-seq genotyping. SCIENCE CHINA-LIFE SCIENCES 2018. [DOI: 10.1007/s11427-017-9161-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Yang Q, Liu X, Zhou T, Cook J, Nguyen K, Bai X. RNA polymerase II pausing modulates hematopoietic stem cell emergence in zebrafish. Blood 2016; 128:1701-10. [PMID: 27520065 PMCID: PMC5043126 DOI: 10.1182/blood-2016-02-697847] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022] Open
Abstract
The promoter-proximal pausing of RNA polymerase II (Pol II) plays a critical role in regulating metazoan gene transcription. Despite the prevalence of Pol II pausing across the metazoan genomes, little is known about the in vivo effect of Pol II pausing on vertebrate development. We use the emergence of hematopoietic stem cells (HSCs) in zebrafish embryos as a model to investigate the role of Pol II pausing in vertebrate organogenesis. Disrupting Pol II pausing machinery causes a severe reduction of HSC specification, a defect that can be effectively rescued by inhibiting Pol II elongation. In pausing-deficient embryos, the transforming growth factor β (TGFβ) signaling is elevated due to enhanced transcription elongation of key pathway genes, leading to HSC inhibition; in contrast, the interferon-γ (IFN-γ) signaling and its downstream effector Jak2/Stat3, which are required for HSC formation, are markedly attenuated owing to reduced chromatin accessibility on IFN-γ receptor genes. These findings reveal a novel transcription mechanism instructing HSC fate by pausing-mediated differential regulation of key signaling pathways.
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Affiliation(s)
- Qiwen Yang
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Xiuli Liu
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Ting Zhou
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jennifer Cook
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Kim Nguyen
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Xiaoying Bai
- Laboratory of Molecular Genetics of Blood Development, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
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Pan H, Zhao X, Zhang X, Abouelsoud M, Sun J, April C, Amleh A, Fan JB, Hu Y, Li R. Translational Initiation at a Non-AUG Start Codon for Human and Mouse Negative Elongation Factor-B. PLoS One 2015; 10:e0127422. [PMID: 26010750 PMCID: PMC4444357 DOI: 10.1371/journal.pone.0127422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 04/15/2015] [Indexed: 12/24/2022] Open
Abstract
Negative elongation factor (NELF), a four-subunit protein complex in metazoan, plays an important role in regulating promoter-proximal pausing of RNA polymerase II (RNAPII). Genetic studies demonstrate that the B subunit of mouse NELF (NELF-B) is critical for embryonic development and homeostasis in adult tissue. We report here that both human and mouse NELF-B proteins are translated from a non-AUG codon upstream of the annotated AUG. This non-AUG codon sequence is conserved in mammalian NELF-B but not NELF-B orthologs of lower metazoan. The full-length and a truncated NELF-B that starts at the first AUG codon both interact with the other three NELF subunits. Furthermore, these two forms of NELF-B have a similar impact on the transcriptomics and proliferation of mouse embryonic fibroblasts. These results strongly suggest that additional amino acid sequence upstream of the annotated AUG is dispensable for the essential NELF function in supporting cell growth in vitro. The majority of mouse adult tissues surveyed express the full-length NELF-B protein, and some contain a truncated NELF-B protein with the same apparent size as the AUG-initiated version. This result raises the distinct possibility that translational initiation of mouse NELF-B is regulated in a tissue-dependent manner.
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Affiliation(s)
- Haihui Pan
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
| | - Xiayan Zhao
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
| | - Xiaowen Zhang
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
| | - Mohamed Abouelsoud
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Jianlong Sun
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
| | - Craig April
- Illumina, Inc., San Diego, CA, 92121, United States of America
| | - Asma Amleh
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Jian-Bing Fan
- Illumina, Inc., San Diego, CA, 92121, United States of America
| | - Yanfen Hu
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
| | - Rong Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, United States of America
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14
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Cabrera JR, Olcese U, Horabin JI. A balancing act: heterochromatin protein 1a and the Polycomb group coordinate their levels to silence chromatin in Drosophila. Epigenetics Chromatin 2015; 8:17. [PMID: 25954320 PMCID: PMC4423169 DOI: 10.1186/s13072-015-0010-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/15/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The small non-histone protein Heterochromatin protein 1a (HP1a) plays a vital role in packaging chromatin, most notably in forming constitutive heterochromatin at the centromeres and telomeres. A second major chromatin regulating system is that of the Polycomb/trithorax groups of genes which, respectively, maintain the repressed/activated state of euchromatin. Recent analyses suggest they affect the expression of a multitude of genes, beyond the homeotics whose alteration in expression lead to their initial discovery. RESULTS Our data suggest that early in Drosophila development, HP1a collaborates with the Polycomb/trithorax groups of proteins to regulate gene expression and that the two chromatin systems do not act separately as convention describes. HP1a affects the levels of both the Polycomb complexes and RNA polymerase II at promoters, as assayed by chromatin immunoprecipitation analysis. Deposition of both the repressive (H3K27me3) and activating (H3K4me3) marks promoted by the Polycomb/trithorax group genes at gene promoters is affected. Additionally, depending on which parent contributes the null mutation of the HP1a gene, the levels of the H3K27me3 and H3K9me3 silencing marks at both promoters and heterochromatin are different. Changes in levels of the H3K27me3 and H3K9me3 repressive marks show a mostly reciprocal nature. The time around the mid-blastula transition, when the zygotic genome begins to be actively transcribed, appears to be a transition/decision point for setting the levels. CONCLUSIONS We find that HP1a, which is normally critical for the formation of constitutive heterochromatin, also affects the generation of the epigenetic marks of the Polycomb/trithorax groups of proteins, chromatin modifiers which are key to maintaining gene expression in euchromatin. At gene promoters, deposition of both the repressive H3K27me3 and activating H3K4me3 marks of histone modifications shows a dependence on HP1a. Around the mid-blastula transition, when the zygotic genome begins to be actively transcribed, a pivotal decision for the level of silencing appears to take place. This is also when the embryo organizes its genome into heterochromatin and euchromatin. A balance between the HP1a and Polycomb group silencing systems appears to be set for the chromatin types that each system will primarily regulate.
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Affiliation(s)
- Janel R Cabrera
- Department of Biomedical Sciences, College of Medicine, Florida State University, Rm 3300-G, 1115 W, Call St., Tallahassee, FL 32306 USA ; Current Address: Center for Life Sciences, Department of Medicine, Division of Cardiology, Beth Israel Deaconess Medical Center, Rm 917, 3 Blackfan Circle, Boston, MA 02215 USA
| | - Ursula Olcese
- Department of Biomedical Sciences, College of Medicine, Florida State University, Rm 3300-G, 1115 W, Call St., Tallahassee, FL 32306 USA
| | - Jamila I Horabin
- Department of Biomedical Sciences, College of Medicine, Florida State University, Rm 3300-G, 1115 W, Call St., Tallahassee, FL 32306 USA
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15
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dDsk2 regulates H2Bub1 and RNA polymerase II pausing at dHP1c complex target genes. Nat Commun 2015; 6:7049. [PMID: 25916810 DOI: 10.1038/ncomms8049] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 03/26/2015] [Indexed: 12/13/2022] Open
Abstract
dDsk2 is a conserved extraproteasomal ubiquitin receptor that targets ubiquitylated proteins for degradation. Here we report that dDsk2 plays a nonproteolytic function in transcription regulation. dDsk2 interacts with the dHP1c complex, localizes at promoters of developmental genes and is required for transcription. Through the ubiquitin-binding domain, dDsk2 interacts with H2Bub1, a modification that occurs at dHP1c complex-binding sites. H2Bub1 is not required for binding of the complex; however, dDsk2 depletion strongly reduces H2Bub1. Co-depletion of the H2Bub1 deubiquitylase dUbp8/Nonstop suppresses this reduction and rescues expression of target genes. RNA polymerase II is strongly paused at promoters of dHP1c complex target genes and dDsk2 depletion disrupts pausing. Altogether, these results suggest that dDsk2 prevents dUbp8/Nonstop-dependent H2Bub1 deubiquitylation at promoters of dHP1c complex target genes and regulates RNA polymerase II pausing. These results expand the catalogue of nonproteolytic functions of ubiquitin receptors to the epigenetic regulation of chromatin modifications.
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16
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Saunders A, Core LJ, Sutcliffe C, Lis JT, Ashe HL. Extensive polymerase pausing during Drosophila axis patterning enables high-level and pliable transcription. Genes Dev 2013; 27:1146-58. [PMID: 23699410 DOI: 10.1101/gad.215459.113] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cascades of zygotic gene expression pattern the anterior-posterior (AP) and dorsal-ventral (DV) axes of the early Drosophila embryo. Here, we used the global run-on sequencing assay (GRO-seq) to map the genome-wide RNA polymerase distribution during early Drosophila embryogenesis, thus providing insights into how genes are regulated. We identify widespread promoter-proximal pausing yet show that the presence of paused polymerase does not necessarily equate to direct regulation through pause release to productive elongation. Our data reveal that a subset of early Zelda-activated genes is regulated at the level of polymerase recruitment, whereas other Zelda target and axis patterning genes are predominantly regulated through pause release. In contrast to other signaling pathways, we found that bone morphogenetic protein (BMP) target genes are collectively more highly paused than BMP pathway components and show that BMP target gene expression requires the pause-inducing negative elongation factor (NELF) complex. Our data also suggest that polymerase pausing allows plasticity in gene activation throughout embryogenesis, as transiently repressed and transcriptionally silenced genes maintain and lose promoter polymerases, respectively. Finally, we provide evidence that the major effect of pausing is on the levels, rather than timing, of transcription. These data are discussed in terms of the efficiency of transcriptional activation required across cell populations during developmental time constraints.
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Affiliation(s)
- Abbie Saunders
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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17
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Harvey R, Schuster E, Jennings BH. Pleiohomeotic interacts with the core transcription elongation factor Spt5 to regulate gene expression in Drosophila. PLoS One 2013; 8:e70184. [PMID: 23894613 PMCID: PMC3718797 DOI: 10.1371/journal.pone.0070184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/17/2013] [Indexed: 11/26/2022] Open
Abstract
The early elongation checkpoint regulated by Positive Transcription Elongation Factor b (P-TEFb) is a critical control point for the expression of many genes. Spt5 interacts directly with RNA polymerase II and has an essential role in establishing this checkpoint, and also for further transcript elongation. Here we demonstrate that Drosophila Spt5 interacts both physically and genetically with the Polycomb Group (PcG) protein Pleiohomeotic (Pho), and the majority of Pho binding sites overlap with Spt5 binding sites across the genome in S2 cells. Our results indicate that Pho can interact with Spt5 to regulate transcription elongation in a gene specific manner.
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Affiliation(s)
- Robert Harvey
- Transcriptional Regulation Group, UCL Cancer Institute, University College London, London, United Kingdom
| | - Eugene Schuster
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Barbara H. Jennings
- Transcriptional Regulation Group, UCL Cancer Institute, University College London, London, United Kingdom
- * E-mail:
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18
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Jennings BH. Pausing for thought: disrupting the early transcription elongation checkpoint leads to developmental defects and tumourigenesis. Bioessays 2013; 35:553-60. [PMID: 23575664 PMCID: PMC3698693 DOI: 10.1002/bies.201200179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/04/2013] [Indexed: 12/30/2022]
Abstract
Factors affecting transcriptional elongation have been characterized extensively in in vitro, single cell (yeast) and cell culture systems; however, data from the context of multicellular organisms has been relatively scarce. While studies in homogeneous cell populations have been highly informative about the underlying molecular mechanisms and prevalence of polymerase pausing, they do not reveal the biological impact of perturbing this regulation in an animal. The core components regulating pausing are expressed in all animal cells and are recruited to the majority of genes, however, disrupting their function often results in discrete phenotypic effects. Mutations in genes encoding key regulators of transcriptional pausing have been recovered from several genetic screens for specific phenotypes or interactions with specific factors in mice, zebrafish and flies. Analysis of these mutations has revealed that control of transcriptional pausing is critical for a diverse range of biological pathways essential for animal development and survival.
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19
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Xu J, Grant G, Sabin LR, Gordesky-Gold B, Yasunaga A, Tudor M, Cherry S. Transcriptional pausing controls a rapid antiviral innate immune response in Drosophila. Cell Host Microbe 2013; 12:531-43. [PMID: 23084920 DOI: 10.1016/j.chom.2012.08.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/27/2012] [Accepted: 08/31/2012] [Indexed: 12/21/2022]
Abstract
Innate immune responses are characterized by precise gene expression whereby gene subsets are temporally induced to limit infection, although the mechanisms involved are incompletely understood. We show that antiviral immunity in Drosophila requires the transcriptional pausing pathway, including negative elongation factor (NELF) that pauses RNA polymerase II (Pol II) and positive elongation factor b (P-TEFb), which releases paused Pol II to produce full-length transcripts. We identify a set of genes that is rapidly transcribed upon arbovirus infection, including components of antiviral pathways (RNA silencing, autophagy, JAK/STAT, Toll, and Imd) and various Toll receptors. Many of these genes require P-TEFb for expression and exhibit pausing-associated chromatin features. Furthermore, transcriptional pausing is critical for antiviral immunity in insects because NELF and P-TEFb are required to restrict viral replication in adult flies and vector mosquito cells. Thus, transcriptional pausing primes virally induced genes to facilitate rapid gene induction and robust antiviral responses.
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Affiliation(s)
- Jie Xu
- Department of Microbiology, Penn Genome Frontiers Institute, University of Pennsylvania, Philadelphia, PA 19146, USA
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20
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Transcription elongation factors DSIF and NELF: promoter-proximal pausing and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012. [PMID: 23202475 DOI: 10.1016/j.bbagrm.2012.11.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF) were originally identified as factors responsible for transcriptional inhibition by 5,6-dichloro-1-beta-d-ribofuranosyl-benzimidazole (DRB) and were later found to control transcription elongation, together with P-TEFb, at the promoter-proximal region. Although there is ample evidence that these factors play roles throughout the genome, other data also suggest gene- or tissue-specific roles for these factors. In this review, we discuss how these apparently conflicting data can be reconciled. In light of recent findings, we also discuss the detailed mechanism by which these factors control the elongation process at the molecular level. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Liu S, Tao Y. Interplay between chromatin modifications and paused RNA polymerase II in dynamic transition between stalled and activated genes. Biol Rev Camb Philos Soc 2012; 88:40-8. [PMID: 22765520 DOI: 10.1111/j.1469-185x.2012.00237.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The dynamic interplay between chromatin modification (e.g. DNA methylation) and RNA polymerase II (Pol II) plays a critical role in gene transcription during stem cell development, establishment, and maintenance and in the cellular response to extracellular stimuli such as those that cause DNA damage. Pol II is recruited to the promoter-proximal regions of numerous inactive genes at high conentrations in a process called Pol II stalling. This is a key process prior to gene activation and it involves many interacting factors. Chromatin modification including nucleosome position is dependent on chromatin structure. Stalled genes create a particular structural conformation of chromatin, which acts as a target for chromatin modification. In this way, Pol II stalling may be regarded as a type of signal for chromatin modification in these regions during the dynamic transition between stalled and activated genes.
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Affiliation(s)
- Shuang Liu
- Cancer Research Institute, Central South University, Changsha, Hunan 410078, China
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22
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Li J, Gilmour DS. Promoter proximal pausing and the control of gene expression. Curr Opin Genet Dev 2011; 21:231-5. [PMID: 21324670 DOI: 10.1016/j.gde.2011.01.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/18/2011] [Indexed: 12/18/2022]
Abstract
The advent of methods for mapping the location of specific proteins across genomes is substantially enlightening our understanding of gene regulation. One recent discovery is that Pol II is concentrated at the 5' end of thousands of genes in mammalian and Drosophila cells. Before this, much research had focused on understanding how sequence-specific, DNA-binding proteins orchestrate the actions of regulators of chromatin structure and the general transcriptional machinery to control transcription initiation. The concentration of Pol II at the 5' ends of genes indicates that key steps regulating transcription occur after Pol II has associated with a gene's promoter.
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Affiliation(s)
- Jian Li
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, United States
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23
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Nechaev S, Adelman K. Pol II waiting in the starting gates: Regulating the transition from transcription initiation into productive elongation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:34-45. [PMID: 21081187 DOI: 10.1016/j.bbagrm.2010.11.001] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/06/2010] [Accepted: 11/09/2010] [Indexed: 01/12/2023]
Abstract
Proper regulation of gene expression is essential for the differentiation, development and survival of all cells and organisms. Recent work demonstrates that transcription of many genes, including key developmental and stimulus-responsive genes, is regulated after the initiation step, by pausing of RNA polymerase II during elongation through the promoter-proximal region. Thus, there is great interest in better understanding the events that follow transcription initiation and the ways in which the efficiency of early elongation can be modulated to impact expression of these highly regulated genes. Here we describe our current understanding of the steps involved in the transition from an unstable initially transcribing complex into a highly stable and processive elongation complex. We also discuss the interplay between factors that affect early transcript elongation and the potential physiological consequences for genes that are regulated through transcriptional pausing.
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Affiliation(s)
- Sergei Nechaev
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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