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Fetian T, Grover A, Arndt KM. Histone H2B ubiquitylation: Connections to transcription and effects on chromatin structure. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195018. [PMID: 38331024 PMCID: PMC11098702 DOI: 10.1016/j.bbagrm.2024.195018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Nucleosomes are major determinants of eukaryotic genome organization and regulation. Many studies, incorporating a diversity of experimental approaches, have been focused on identifying and discerning the contributions of histone post-translational modifications to DNA-centered processes. Among these, monoubiquitylation of H2B (H2Bub) on K120 in humans or K123 in budding yeast is a critical histone modification that has been implicated in a wide array of DNA transactions. H2B is co-transcriptionally ubiquitylated and deubiquitylated via the concerted action of an extensive network of proteins. In addition to altering the chemical and physical properties of the nucleosome, H2Bub is important for the proper control of gene expression and for the deposition of other histone modifications. In this review, we discuss the molecular mechanisms underlying the ubiquitylation cycle of H2B and how it connects to the regulation of transcription and chromatin structure.
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Affiliation(s)
- Tasniem Fetian
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - Aakash Grover
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States of America.
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2
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Liu Y, Shu J, Zhang Z, Ding N, Liu J, Liu J, Cui Y, Wang C, Chen C. A conserved Pol II elongator SPT6L mediates Pol V transcription to regulate RNA-directed DNA methylation in Arabidopsis. Nat Commun 2024; 15:4460. [PMID: 38796517 PMCID: PMC11127964 DOI: 10.1038/s41467-024-48940-8] [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: 07/04/2023] [Accepted: 05/14/2024] [Indexed: 05/28/2024] Open
Abstract
In plants, the plant-specific RNA polymerase V (Pol V) transcripts non-coding RNAs and provides a docking platform for the association of accessory proteins in the RNA-directed DNA methylation (RdDM) pathway. Various components have been uncovered that are involved in the process of DNA methylation, but it is still not clear how the transcription of Pol V is regulated. Here, we report that the conserved RNA polymerase II (Pol II) elongator, SPT6L, binds to thousands of intergenic regions in a Pol II-independent manner. The intergenic enrichment of SPT6L, interestingly, co-occupies with the largest subunit of Pol V (NRPE1) and mutation of SPT6L leads to the reduction of DNA methylation but not Pol V enrichment. Furthermore, the association of SPT6L at Pol V loci is dependent on the Pol V associated factor, SPT5L, rather than the presence of Pol V, and the interaction between SPT6L and NRPE1 is compromised in spt5l. Finally, Pol V RIP-seq reveals that SPT6L is required to maintain the amount and length of Pol V transcripts. Our findings thus uncover the critical role of a Pol II conserved elongator in Pol V mediated DNA methylation and transcription, and shed light on the mutual regulation between Pol V and II in plants.
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Affiliation(s)
- Yujuan Liu
- State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Jie Shu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Zhi Zhang
- State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Ning Ding
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jinyuan Liu
- State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Jun Liu
- Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, 510640, China
| | - Yuhai Cui
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON, N5V 4T3, Canada
- Department of Biology, Western University, London, ON, N6A 5B7, Canada
| | - Changhu Wang
- State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China.
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China.
- University of the Chinese Academy of Sciences, Beijing, 100049, China.
| | - Chen Chen
- State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China.
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong, 510650, China.
- University of the Chinese Academy of Sciences, Beijing, 100049, China.
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3
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Soliman SHA, Iwanaszko M, Zheng B, Gold S, Howard BC, Das M, Chakrabarty RP, Chandel NS, Shilatifard A. Transcriptional elongation control of hypoxic response. Proc Natl Acad Sci U S A 2024; 121:e2321502121. [PMID: 38564636 PMCID: PMC11009653 DOI: 10.1073/pnas.2321502121] [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: 12/06/2023] [Accepted: 02/23/2024] [Indexed: 04/04/2024] Open
Abstract
The release of paused RNA polymerase II (RNAPII) from promoter-proximal regions is tightly controlled to ensure proper regulation of gene expression. The elongation factor PTEF-b is known to release paused RNAPII via phosphorylation of the RNAPII C-terminal domain by its cyclin-dependent kinase component, CDK9. However, the signal and stress-specific roles of the various RNAPII-associated macromolecular complexes containing PTEF-b/CDK9 are not yet clear. Here, we identify and characterize the CDK9 complex required for transcriptional response to hypoxia. Contrary to previous reports, our data indicate that a CDK9 complex containing BRD4 but not AFF1/4 is essential for this hypoxic stress response. We demonstrate that BRD4 bromodomains (BET) are dispensable for the release of paused RNAPII at hypoxia-activated genes and that BET inhibition by JQ1 is insufficient to impair hypoxic gene response. Mechanistically, we demonstrate that the C-terminal region of BRD4 is required for Polymerase-Associated Factor-1 Complex (PAF1C) recruitment to establish an elongation-competent RNAPII complex at hypoxia-responsive genes. PAF1C disruption using a small-molecule inhibitor (iPAF1C) impairs hypoxia-induced, BRD4-mediated RNAPII release. Together, our results provide insight into potentially targetable mechanisms that control the hypoxia-responsive transcriptional elongation.
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Affiliation(s)
- Shimaa Hassan AbdelAziz Soliman
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Marta Iwanaszko
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Bin Zheng
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Sarah Gold
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Benjamin Charles Howard
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Madhurima Das
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Ram Prosad Chakrabarty
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University, Chicago, IL60611
| | - Navdeep S. Chandel
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
- Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University, Chicago, IL60611
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
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4
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Mbonye U, Karn J. The cell biology of HIV-1 latency and rebound. Retrovirology 2024; 21:6. [PMID: 38580979 PMCID: PMC10996279 DOI: 10.1186/s12977-024-00639-w] [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] [Indexed: 04/07/2024] Open
Abstract
Transcriptionally latent forms of replication-competent proviruses, present primarily in a small subset of memory CD4+ T cells, pose the primary barrier to a cure for HIV-1 infection because they are the source of the viral rebound that almost inevitably follows the interruption of antiretroviral therapy. Over the last 30 years, many of the factors essential for initiating HIV-1 transcription have been identified in studies performed using transformed cell lines, such as the Jurkat T-cell model. However, as highlighted in this review, several poorly understood mechanisms still need to be elucidated, including the molecular basis for promoter-proximal pausing of the transcribing complex and the detailed mechanism of the delivery of P-TEFb from 7SK snRNP. Furthermore, the central paradox of HIV-1 transcription remains unsolved: how are the initial rounds of transcription achieved in the absence of Tat? A critical limitation of the transformed cell models is that they do not recapitulate the transitions between active effector cells and quiescent memory T cells. Therefore, investigation of the molecular mechanisms of HIV-1 latency reversal and LRA efficacy in a proper physiological context requires the utilization of primary cell models. Recent mechanistic studies of HIV-1 transcription using latently infected cells recovered from donors and ex vivo cellular models of viral latency have demonstrated that the primary blocks to HIV-1 transcription in memory CD4+ T cells are restrictive epigenetic features at the proviral promoter, the cytoplasmic sequestration of key transcription initiation factors such as NFAT and NF-κB, and the vanishingly low expression of the cellular transcription elongation factor P-TEFb. One of the foremost schemes to eliminate the residual reservoir is to deliberately reactivate latent HIV-1 proviruses to enable clearance of persisting latently infected cells-the "Shock and Kill" strategy. For "Shock and Kill" to become efficient, effective, non-toxic latency-reversing agents (LRAs) must be discovered. Since multiple restrictions limit viral reactivation in primary cells, understanding the T-cell signaling mechanisms that are essential for stimulating P-TEFb biogenesis, initiation factor activation, and reversing the proviral epigenetic restrictions have become a prerequisite for the development of more effective LRAs.
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Affiliation(s)
- Uri Mbonye
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
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5
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Su BG, Vos SM. Distinct negative elongation factor conformations regulate RNA polymerase II promoter-proximal pausing. Mol Cell 2024; 84:1243-1256.e5. [PMID: 38401543 PMCID: PMC10997474 DOI: 10.1016/j.molcel.2024.01.023] [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: 10/11/2023] [Revised: 12/17/2023] [Accepted: 01/25/2024] [Indexed: 02/26/2024]
Abstract
Metazoan gene expression regulation involves pausing of RNA polymerase (Pol II) in the promoter-proximal region of genes and is stabilized by DSIF and NELF. Upon depletion of elongation factors, NELF appears to accompany elongating Pol II past pause sites; however, prior work indicates that NELF prevents Pol II elongation. Here, we report cryoelectron microscopy structures of Pol II-DSIF-NELF complexes with NELF in two distinct conformations corresponding to paused and poised states. The paused NELF state supports Pol II stalling, whereas the poised NELF state enables transcription elongation as it does not support a tilted RNA-DNA hybrid. Further, the poised NELF state can accommodate TFIIS binding to Pol II, allowing for Pol II reactivation at paused or backtracking sites. Finally, we observe that the NELF-A tentacle interacts with the RPB2 protrusion and is necessary for pausing. Our results define how NELF can support pausing, reactivation, and elongation by Pol II.
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Affiliation(s)
- Bonnie G Su
- Department of Biology, Massachusetts Institute of Technology, Building 68, 31 Ames St., Cambridge, MA 02139, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, Building 68, 31 Ames St., Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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6
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Richter WF, Taatjes DJ. Changing structures, changing paradigms: NELF helps regulate paused or elongating RNA polymerase II. Mol Cell 2024; 84:1180-1182. [PMID: 38579674 DOI: 10.1016/j.molcel.2024.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 03/12/2024] [Accepted: 03/12/2024] [Indexed: 04/07/2024]
Abstract
Using cryo-EM and biochemical methods, Su and Vos1 discover an alternative NELF structural state that enables transcription and switches NELF-RNA polymerase II (RNAPII) compatibility with other RNAPII-associated factors that regulate pausing, elongation, termination, and transcription-coupled DNA repair.
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Affiliation(s)
- William F Richter
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA.
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7
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Barman P, Ferdoush J, Kaja A, Chakraborty P, Uprety B, Bhaumik R, Bhaumik R, Bhaumik SR. Ubiquitin-proteasome system regulation of a key gene regulatory factor, Paf1C. Gene 2024; 894:148004. [PMID: 37977317 DOI: 10.1016/j.gene.2023.148004] [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: 08/07/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Paf1 (Polymerase-associated factor 1) complex (Paf1C) is evolutionarily conserved from yeast to humans, and facilitates transcription elongation as well as co-transcriptional histone covalent modifications and mRNA 3'-end processing. Thus, Paf1C is a key player in regulation of eukaryotic gene expression. Paf1C consists of Paf1, Cdc73, Ctr9, Leo1 and Rtf1 in both yeast and humans, but it has an additional component, Ski8, in humans. The abundances of these components regulate the assembly of Paf1C and/or its functions, thus implying the mechanisms involved in regulating the abundances of the Paf1C components in altered gene expression and hence cellular pathologies. Towards finding the mechanisms associated with the abundances of the Paf1C components, we analyzed here whether the Paf1C components are regulated via targeted ubiquitylation and 26S proteasomal degradation. We find that the Paf1C components except Paf1 do not undergo the 26S proteasomal degradation in both yeast and humans. Paf1 is found to be regulated by the ubiquitin-proteasome system (UPS) in yeast and humans. Alteration of such regulation changes Paf1's abundance, leading to aberrant gene expression. Intriguingly, while the Rtf1 component of Paf1C does not undergo the 26S proteasomal degradation, it is found to be ubiquitylated, suggesting that Rtf1 ubiquitylation could be engaged in Paf1C assembly and/or functions. Collectively, our results reveal distinct UPS regulation of the Paf1C components, Paf1 and Rtf1, in a proteolysis-dependent and -independent manners, respectively, with functional implications.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Jannatul Ferdoush
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Amala Kaja
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Pritam Chakraborty
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Bhawana Uprety
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Rhea Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Risa Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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8
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Lu F, Park BJ, Fujiwara R, Wilusz JE, Gilmour DS, Lehmann R, Lionnet T. Integrator-mediated clustering of poised RNA polymerase II synchronizes histone transcription. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.07.561364. [PMID: 37873455 PMCID: PMC10592978 DOI: 10.1101/2023.10.07.561364] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Numerous components of the transcription machinery, including RNA polymerase II (Pol II), accumulate in regions of high local concentration known as clusters, which are thought to facilitate transcription. Using the histone locus of Drosophila nurse cells as a model, we find that Pol II forms long-lived, transcriptionally poised clusters distinct from liquid droplets, which contain unbound and paused Pol II. Depletion of the Integrator complex endonuclease module, but not its phosphatase module or Pol II pausing factors disperses these Pol II clusters. Consequently, histone transcription fails to reach peak levels during S-phase and aberrantly continues throughout the cell cycle. We propose that Pol II clustering is a regulatory step occurring near promoters that limits rapid gene activation to defined times. One Sentence Summary Using the Drosophila histone locus as a model, we show that clustered RNA polymerase II is poised for synchronous activation.
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9
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Layden HM, Johnson AE, Hiebert SW. Chemical-genetics refines transcription factor regulatory circuits. Trends Cancer 2024; 10:65-75. [PMID: 37722945 PMCID: PMC10840957 DOI: 10.1016/j.trecan.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/14/2023] [Accepted: 08/25/2023] [Indexed: 09/20/2023]
Abstract
Transcriptional dysregulation is a key step in oncogenesis, but our understanding of transcriptional control has relied on genetic approaches that are slow and allow for compensation. Chemical-genetic approaches have shortened the time frame for the analysis of transcription factors from days or weeks to minutes. These studies show that while DNA-binding proteins bind to thousands of sites, they are directly required to regulate only a small cadre of genes. Moreover, these transcriptional control networks are far more distinct, with much less overlap and interconnectivity than predicted from DNA binding. The identified direct targets can then be used to dissect the mechanism of action of these factors, which could identify ways to therapeutically manipulate these oncogenic transcriptional control networks.
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Affiliation(s)
- Hillary M Layden
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Anna E Johnson
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Nashville, TN 37027, USA.
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10
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Zhao Z, Aoi Y, Philips CN, Meghani KA, Gold SR, Yu Y, John LS, Qian J, Zeidner JM, Meeks JJ, Shilatifard A. Somatic mutations of MLL4/COMPASS induce cytoplasmic localization providing molecular insight into cancer prognosis and treatment. Proc Natl Acad Sci U S A 2023; 120:e2310063120. [PMID: 38113256 PMCID: PMC10756272 DOI: 10.1073/pnas.2310063120] [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: 06/14/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023] Open
Abstract
Cancer genome sequencing consortiums have recently catalogued an abundance of somatic mutations, across a wide range of human cancers, in the chromatin-modifying enzymes that regulate gene expression. Defining the molecular mechanisms underlying the potentially oncogenic functions of these epigenetic mutations could serve as the basis for precision medicine approaches to cancer therapy. MLL4 encoded by the KMT2D gene highly mutated in a large number of human cancers, is a key histone lysine monomethyltransferase within the Complex of Proteins Associated with Set1 (COMPASS) family that regulates gene expression through enhancer function, potentially functioning as a tumor suppressor. We report that the KMT2D mutations which cause MLL4 protein truncation also alter MLL4's subcellular localization, resulting in loss-of-function in the nucleus and gain-of-function in the cytoplasm. We demonstrate that isogenic correction of KMT2D truncation mutation rescues the aberrant localization phenotype and restores multiple regulatory functions of MLL4, including COMPASS integrity/stabilization, histone H3K4 mono-methylation, enhancer activation, and therefore transcriptional regulation. Moreover, isogenic correction diminishes the sensitivity of KMT2D-mutated cancer cells to targeted metabolic inhibition. Using immunohistochemistry, we identified that cytoplasmic MLL4 is unique to the tissue of bladder cancer patients with KMT2D truncation mutations. Using a preclinical carcinogen model of bladder cancer in mouse, we demonstrate that truncated cytoplasmic MLL4 predicts response to targeted metabolic inhibition therapy for bladder cancer and could be developed as a biomarker for KMT2D-mutated cancers. We also highlight the broader potential for prognosis, patient stratification and treatment decision-making based on KMT2D mutation status in MLL4 truncation-relevant diseases, including human cancers and Kabuki Syndrome.
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Affiliation(s)
- Zibo Zhao
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Yuki Aoi
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Cassandra N. Philips
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Khyati A. Meghani
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Sarah R. Gold
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Yanni Yu
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Luke St John
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jun Qian
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Jacob M. Zeidner
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Joshua J. Meeks
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
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11
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Morgan MA, Mohammad Parast S, Iwanaszko M, Aoi Y, Yoo D, Dumar ZJ, Howard BC, Helmin KA, Liu Q, Thakur WR, Zeidner JM, Singer BD, Eichler EE, Shilatifard A. ELOA3: A primate-specific RNA polymerase II elongation factor encoded by a tandem repeat gene cluster. SCIENCE ADVANCES 2023; 9:eadj1261. [PMID: 37992162 PMCID: PMC10664989 DOI: 10.1126/sciadv.adj1261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 10/19/2023] [Indexed: 11/24/2023]
Abstract
The biological role of the repetitive DNA sequences in the human genome remains an outstanding question. Recent long-read human genome assemblies have allowed us to identify a function for one of these repetitive regions. We have uncovered a tandem array of conserved primate-specific retrogenes encoding the protein Elongin A3 (ELOA3), a homolog of the RNA polymerase II (RNAPII) elongation factor Elongin A (ELOA). Our genomic analysis shows that the ELOA3 gene cluster is conserved among primates and the number of ELOA3 gene repeats is variable in the human population and across primate species. Moreover, the gene cluster has undergone concerted evolution and homogenization within primates. Our biochemical studies show that ELOA3 functions as a promoter-associated RNAPII pause-release elongation factor with distinct biochemical and functional features from its ancestral homolog, ELOA. We propose that the ELOA3 gene cluster has evolved to fulfil a transcriptional regulatory function unique to the primate lineage that can be targeted to regulate cellular hyperproliferation.
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Affiliation(s)
- Marc A. J. Morgan
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Saeid Mohammad Parast
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Marta Iwanaszko
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yuki Aoi
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - DongAhn Yoo
- Department of Genome Sciences, University of Washington School of Medicine; Seattle, WA 98195, USA
| | - Zachary J. Dumar
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Benjamin C. Howard
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kathryn A. Helmin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Simpson Querrey Lung Institute for Translational Science, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Qianli Liu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Simpson Querrey Lung Institute for Translational Science, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - William R. Thakur
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jacob M. Zeidner
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Benjamin D. Singer
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Simpson Querrey Lung Institute for Translational Science, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine; Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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12
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Aoi Y, Shilatifard A. Transcriptional elongation control in developmental gene expression, aging, and disease. Mol Cell 2023; 83:3972-3999. [PMID: 37922911 DOI: 10.1016/j.molcel.2023.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/23/2023] [Accepted: 10/11/2023] [Indexed: 11/07/2023]
Abstract
The elongation stage of transcription by RNA polymerase II (RNA Pol II) is central to the regulation of gene expression in response to developmental and environmental cues in metazoan. Dysregulated transcriptional elongation has been associated with developmental defects as well as disease and aging processes. Decades of genetic and biochemical studies have painstakingly identified and characterized an ensemble of factors that regulate RNA Pol II elongation. This review summarizes recent findings taking advantage of genetic engineering techniques that probe functions of elongation factors in vivo. We propose a revised model of elongation control in this accelerating field by reconciling contradictory results from the earlier biochemical evidence and the recent in vivo studies. We discuss how elongation factors regulate promoter-proximal RNA Pol II pause release, transcriptional elongation rate and processivity, RNA Pol II stability and RNA processing, and how perturbation of these processes is associated with developmental disorders, neurodegenerative disease, cancer, and aging.
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Affiliation(s)
- Yuki Aoi
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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13
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Miller CLW, Warner JL, Winston F. Insights into Spt6: a histone chaperone that functions in transcription, DNA replication, and genome stability. Trends Genet 2023; 39:858-872. [PMID: 37481442 PMCID: PMC10592469 DOI: 10.1016/j.tig.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/24/2023]
Abstract
Transcription elongation requires elaborate coordination between the transcriptional machinery and chromatin regulatory factors to successfully produce RNA while preserving the epigenetic landscape. Recent structural and genomic studies have highlighted that suppressor of Ty 6 (Spt6), a conserved histone chaperone and transcription elongation factor, sits at the crux of the transcription elongation process. Other recent studies have revealed that Spt6 also promotes DNA replication and genome integrity. Here, we review recent studies of Spt6 that have provided new insights into the mechanisms by which Spt6 controls transcription and have revealed the breadth of Spt6 functions in eukaryotic cells.
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Affiliation(s)
- Catherine L W Miller
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Laboratory of Genome Maintenance, Rockefeller University, New York, NY 10065, USA
| | - James L Warner
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Fred Winston
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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14
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Jha RK, Kouzine F, Levens D. MYC function and regulation in physiological perspective. Front Cell Dev Biol 2023; 11:1268275. [PMID: 37941901 PMCID: PMC10627926 DOI: 10.3389/fcell.2023.1268275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/12/2023] [Indexed: 11/10/2023] Open
Abstract
MYC, a key member of the Myc-proto-oncogene family, is a universal transcription amplifier that regulates almost every physiological process in a cell including cell cycle, proliferation, metabolism, differentiation, and apoptosis. MYC interacts with several cofactors, chromatin modifiers, and regulators to direct gene expression. MYC levels are tightly regulated, and deregulation of MYC has been associated with numerous diseases including cancer. Understanding the comprehensive biology of MYC under physiological conditions is an utmost necessity to demark biological functions of MYC from its pathological functions. Here we review the recent advances in biological mechanisms, functions, and regulation of MYC. We also emphasize the role of MYC as a global transcription amplifier.
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Affiliation(s)
| | | | - David Levens
- Gene Regulation Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute (NCI), Bethesda, MD, United States
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15
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Zheng B, Gold S, Iwanaszko M, Howard BC, Wang L, Shilatifard A. Distinct layers of BRD4-PTEFb reveal bromodomain-independent function in transcriptional regulation. Mol Cell 2023; 83:2896-2910.e4. [PMID: 37442129 PMCID: PMC10527981 DOI: 10.1016/j.molcel.2023.06.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/15/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023]
Abstract
The BET family protein BRD4, which forms the CDK9-containing BRD4-PTEFb complex, is considered to be a master regulator of RNA polymerase II (Pol II) pause release. Because its tandem bromodomains interact with acetylated histone lysine residues, it has long been thought that BRD4 requires these bromodomains for its recruitment to chromatin and transcriptional regulatory function. Here, using rapid depletion and genetic complementation with domain deletion mutants, we demonstrate that BRD4 bromodomains are dispensable for Pol II pause release. A minimal, bromodomain-less C-terminal BRD4 fragment containing the PTEFb-interacting C-terminal motif (CTM) is instead both necessary and sufficient to mediate Pol II pause release in the absence of full-length BRD4. Although BRD4-PTEFb can associate with chromatin through acetyl recognition, our results indicate that a distinct, active BRD4-PTEFb population functions to regulate transcription independently of bromodomain-mediated chromatin association. These findings may enable more effective pharmaceutical modulation of BRD4-PTEFb activity.
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Affiliation(s)
- Bin Zheng
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sarah Gold
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Marta Iwanaszko
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Benjamin Charles Howard
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lu Wang
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics and the Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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16
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Estell C, Davidson L, Eaton JD, Kimura H, Gold VAM, West S. A restrictor complex of ZC3H4, WDR82, and ARS2 integrates with PNUTS to control unproductive transcription. Mol Cell 2023:S1097-2765(23)00385-4. [PMID: 37329883 DOI: 10.1016/j.molcel.2023.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/29/2023] [Accepted: 05/18/2023] [Indexed: 06/19/2023]
Abstract
The transcriptional termination of unstable non-coding RNAs (ncRNAs) is poorly understood compared to coding transcripts. We recently identified ZC3H4-WDR82 ("restrictor") as restricting human ncRNA transcription, but how it does this is unknown. Here, we show that ZC3H4 additionally associates with ARS2 and the nuclear exosome targeting complex. The domains of ZC3H4 that contact ARS2 and WDR82 are required for ncRNA restriction, suggesting their presence in a functional complex. Consistently, ZC3H4, WDR82, and ARS2 co-transcriptionally control an overlapping population of ncRNAs. ZC3H4 is proximal to the negative elongation factor, PNUTS, which we show enables restrictor function and is required to terminate the transcription of all major RNA polymerase II transcript classes. In contrast to short ncRNAs, longer protein-coding transcription is supported by U1 snRNA, which shields transcripts from restrictor and PNUTS at hundreds of genes. These data provide important insights into the mechanism and control of transcription by restrictor and PNUTS.
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Affiliation(s)
- Chris Estell
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Lee Davidson
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Joshua D Eaton
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Hiroshi Kimura
- Cell Biology Centre, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
| | - Vicki A M Gold
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Steven West
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom.
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17
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Ellison MA, Namjilsuren S, Shirra M, Blacksmith M, Schusteff R, Kerr E, Fang F, Xiang Y, Shi Y, Arndt K. Spt6 directly interacts with Cdc73 and is required for Paf1 complex occupancy at active genes in Saccharomyces cerevisiae. Nucleic Acids Res 2023; 51:4814-4830. [PMID: 36928138 PMCID: PMC10250246 DOI: 10.1093/nar/gkad180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 03/18/2023] Open
Abstract
The Paf1 complex (Paf1C) is a conserved transcription elongation factor that regulates transcription elongation efficiency, facilitates co-transcriptional histone modifications, and impacts molecular processes linked to RNA synthesis, such as polyA site selection. Coupling of the activities of Paf1C to transcription elongation requires its association with RNA polymerase II (Pol II). Mutational studies in yeast identified Paf1C subunits Cdc73 and Rtf1 as important mediators of Paf1C association with Pol II on active genes. While the interaction between Rtf1 and the general elongation factor Spt5 is relatively well-understood, the interactions involving Cdc73 have not been fully elucidated. Using a site-specific protein cross-linking strategy in yeast cells, we identified direct interactions between Cdc73 and two components of the Pol II elongation complex, the elongation factor Spt6 and the largest subunit of Pol II. Both of these interactions require the tandem SH2 domain of Spt6. We also show that Cdc73 and Spt6 can interact in vitro and that rapid depletion of Spt6 dissociates Paf1 from chromatin, altering patterns of Paf1C-dependent histone modifications genome-wide. These results reveal interactions between Cdc73 and the Pol II elongation complex and identify Spt6 as a key factor contributing to the occupancy of Paf1C at active genes in Saccharomyces cerevisiae.
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Affiliation(s)
- Mitchell A Ellison
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | - Margaret K Shirra
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Matthew S Blacksmith
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Rachel A Schusteff
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Eleanor M Kerr
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Fei Fang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yufei Xiang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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18
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DeBerardine M, Booth GT, Versluis PP, Lis JT. The NELF pausing checkpoint mediates the functional divergence of Cdk9. Nat Commun 2023; 14:2762. [PMID: 37179384 PMCID: PMC10182999 DOI: 10.1038/s41467-023-38359-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Promoter-proximal pausing by RNA Pol II is a rate-determining step in gene transcription that is hypothesized to be a prominent point at which regulatory factors act. The pausing factor NELF is known to induce and stabilize pausing, but not all kinds of pausing are NELF-mediated. Here, we find that NELF-depleted Drosophila melanogaster cells functionally recapitulate the NELF-independent pausing we previously observed in fission yeast (which lack NELF). Critically, only NELF-mediated pausing establishes a strict requirement for Cdk9 kinase activity for the release of paused Pol II into productive elongation. Upon inhibition of Cdk9, cells with NELF efficiently shutdown gene transcription, while in NELF-depleted cells, defective, non-productive transcription continues unabated. By introducing a strict checkpoint for Cdk9, the evolution of NELF was likely critical to enable increased regulation of Cdk9 in higher eukaryotes, as Cdk9 availability can be restricted to limit gene transcription without inducing wasteful, non-productive transcription.
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Affiliation(s)
- Michael DeBerardine
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Gregory T Booth
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Kanvas Biosciences, Monmouth Junction, NJ, USA
| | - Philip P Versluis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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19
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Kenaston MW, Shah PS. The Archer and the Prey: The Duality of PAF1C in Antiviral Immunity. Viruses 2023; 15:v15051032. [PMID: 37243120 DOI: 10.3390/v15051032] [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: 03/29/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
In the ongoing arms race between virus and host, fine-tuned gene expression plays a critical role in antiviral signaling. However, viruses have evolved to disrupt this process and promote their own replication by targeting host restriction factors. Polymerase-associated factor 1 complex (PAF1C) is a key player in this relationship, recruiting other host factors to regulate transcription and modulate innate immune gene expression. Consequently, PAF1C is consistently targeted by a diverse range of viruses, either to suppress its antiviral functions or co-opt them for their own benefit. In this review, we delve into the current mechanisms through which PAF1C restricts viruses by activating interferon and inflammatory responses at the transcriptional level. We also highlight how the ubiquity of these mechanisms makes PAF1C especially vulnerable to viral hijacking and antagonism. Indeed, as often as PAF1C is revealed to be a restriction factor, viruses are found to have targeted the complex in reply.
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Affiliation(s)
- Matthew W Kenaston
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Priya S Shah
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
- Department of Chemical Engineering, University of California, Davis, CA 95616, USA
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20
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Hu S, Peng L, Song A, Ji YX, Cheng J, Wang M, Chen FX. INTAC endonuclease and phosphatase modules differentially regulate transcription by RNA polymerase II. Mol Cell 2023; 83:1588-1604.e5. [PMID: 37080207 DOI: 10.1016/j.molcel.2023.03.022] [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: 09/20/2022] [Revised: 02/14/2023] [Accepted: 03/23/2023] [Indexed: 04/22/2023]
Abstract
Gene expression in metazoans is controlled by promoter-proximal pausing of RNA polymerase II, which can undergo productive elongation or promoter-proximal termination. Integrator-PP2A (INTAC) plays a crucial role in determining the fate of paused polymerases, but the underlying mechanisms remain unclear. Here, we establish a rapid degradation system to dissect the functions of INTAC RNA endonuclease and phosphatase modules. We find that both catalytic modules function at most if not all active promoters and enhancers, yet differentially affect polymerase fate. The endonuclease module induces promoter-proximal termination, with its disruption leading to accumulation of elongation-incompetent polymerases and downregulation of highly expressed genes, while elongation-competent polymerases accumulate at lowly expressed genes and non-coding elements, leading to their upregulation. The phosphatase module primarily prevents the release of paused polymerases and limits transcriptional activation, especially for highly paused genes. Thus, both INTAC catalytic modules have unexpectedly general yet distinct roles in dynamic transcriptional control.
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Affiliation(s)
- Shibin Hu
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Linna Peng
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Aixia Song
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yu-Xin Ji
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jingdong Cheng
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Mengyun Wang
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Fei Xavier Chen
- Fudan University Shanghai Cancer Center, Shanghai Key Laboratory of Medical Epigenetics, Human Phenome Institute, Shanghai Key Laboratory of Radiation Oncology, Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
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21
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Soliman SH, Cisneros WJ, Iwanaszko M, Aoi Y, Ganesan S, Walter M, Zeidner JM, Mishra RK, Kim EY, Wolinsky SM, Hultquist JF, Shilatifard A. Enhancing HIV-1 latency reversal through regulating the elongating RNA Pol II pause-release by a small-molecule disruptor of PAF1C. SCIENCE ADVANCES 2023; 9:eadf2468. [PMID: 36888719 PMCID: PMC9995073 DOI: 10.1126/sciadv.adf2468] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 02/03/2023] [Indexed: 05/03/2023]
Abstract
The polymerase-associated factor 1 complex (PAF1C) is a key, post-initiation transcriptional regulator of both promoter-proximal pausing and productive elongation catalyzed by RNA Pol II and is also involved in transcriptional repression of viral gene expression during human immunodeficiency virus-1 (HIV-1) latency. Using a molecular docking-based compound screen in silico and global sequencing-based candidate evaluation in vivo, we identified a first-in-class, small-molecule inhibitor of PAF1C (iPAF1C) that disrupts PAF1 chromatin occupancy and induces global release of promoter-proximal paused RNA Pol II into gene bodies. Transcriptomic analysis revealed that iPAF1C treatment mimics acute PAF1 subunit depletion and impairs RNA Pol II pausing at heat shock-down-regulated genes. Furthermore, iPAF1C enhances the activity of diverse HIV-1 latency reversal agents both in cell line latency models and in primary cells from persons living with HIV-1. In sum, this study demonstrates that efficient disruption of PAF1C by a first-in-class, small-molecule inhibitor may have therapeutic potential for improving current HIV-1 latency reversal strategies.
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Affiliation(s)
- Shimaa H. A. Soliman
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - William J. Cisneros
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Center for Pathogen Genomics and Microbial Evolution, Havey Institute for Global Health, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Marta Iwanaszko
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Yuki Aoi
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Sheetal Ganesan
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Miriam Walter
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jacob M. Zeidner
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Rama K. Mishra
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Eun-Young Kim
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Steven M. Wolinsky
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Judd F. Hultquist
- Division of Infectious Diseases, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Center for Pathogen Genomics and Microbial Evolution, Havey Institute for Global Health, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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22
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Knowing when to stop: Transcription termination on protein-coding genes by eukaryotic RNAPII. Mol Cell 2023; 83:404-415. [PMID: 36634677 PMCID: PMC7614299 DOI: 10.1016/j.molcel.2022.12.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023]
Abstract
Gene expression is controlled in a dynamic and regulated manner to allow for the consistent and steady expression of some proteins as well as the rapidly changing production of other proteins. Transcription initiation has been a major focus of study because it is highly regulated. However, termination of transcription also plays an important role in controlling gene expression. Transcription termination on protein-coding genes is intimately linked with 3' end cleavage and polyadenylation of transcripts, and it generally results in the production of a mature mRNA that is exported from the nucleus. Termination on many non-coding genes can also result in the production of a mature transcript. Termination is dynamically regulated-premature termination and transcription readthrough occur in response to a number of cellular signals, and these can have varied consequences on gene expression. Here, we review eukaryotic transcription termination by RNA polymerase II (RNAPII), focusing on protein-coding genes.
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23
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Wang X, Fan Y, Wu Q. The regulation of transcription elongation in embryonic stem cells. Front Cell Dev Biol 2023; 11:1145611. [PMID: 36875763 PMCID: PMC9978399 DOI: 10.3389/fcell.2023.1145611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
Transcription elongation is a fundamental molecular process which is accurately regulated to ensure proper gene expression in cellular activities whereas its malfunction is associated with impaired cellular functions. Embryonic stem cells (ESCs) have significant value in regenerative medicine due to their self-renewal ability and their potential to differentiate to almost all types of cells. Therefore, dissection of the exact regulatory mechanism of transcription elongation in ESCs is crucial for both basic research and their clinical applications. In this review, we discuss the current understanding on the regulatory mechanisms of transcription elongation mediated by transcription factors and epigenetic modifications in ESCs.
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Affiliation(s)
- Xuepeng Wang
- The State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Yudan Fan
- The State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Qiang Wu
- The State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
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24
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RNA Polymerase II “Pause” Prepares Promoters for Upcoming Transcription during Drosophila Development. Int J Mol Sci 2022; 23:ijms231810662. [PMID: 36142573 PMCID: PMC9503990 DOI: 10.3390/ijms231810662] [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: 08/12/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/17/2022] Open
Abstract
According to previous studies, during Drosophila embryogenesis, the recruitment of RNA polymerase II precedes active gene transcription. This work is aimed at exploring whether this mechanism is used during Drosophila metamorphosis. In addition, the composition of the RNA polymerase II “paused” complexes associated with promoters at different developmental stages are described in detail. For this purpose, we performed ChIP-Seq analysis using antibodies for various modifications of RNA polymerase II (total, Pol II CTD Ser5P, and Pol II CTD Ser2P) as well as for subunits of the NELF, DSIF, and PAF complexes and Brd4/Fs(1)h that control transcription elongation. We found that during metamorphosis, similar to mid-embryogenesis, the promoters were bound by RNA polymerase II in the “paused” state, preparing for activation at later stages of development. During mid-embryogenesis, RNA polymerase II in a “pause” state was phosphorylated at Ser5 and Ser2 of Pol II CTD and bound the NELF, DSIF, and PAF complexes, but not Brd4/Fs(1)h. During metamorphosis, the “paused” RNA polymerase II complex included Brd4/Fs(1)h in addition to NELF, DSIF, and PAF. The RNA polymerase II in this complex was phosphorylated at Ser5 of Pol II CTD, but not at Ser2. These results indicate that, during mid-embryogenesis, RNA polymerase II stalls in the “post-pause” state, being phosphorylated at Ser2 of Pol II CTD (after the stage of p-TEFb action). During metamorphosis, the “pause” mechanism is closer to classical promoter-proximal pausing and is characterized by a low level of Pol II CTD Ser2P.
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