1
|
Galan C, Lu G, Gill R, Li D, Liu Y, Huh JR, Hang S. RTF1 mediates epigenetic control of Th17 cell differentiation via H2B monoubiquitination. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2025; 214:vkae043. [PMID: 40073106 PMCID: PMC11952878 DOI: 10.1093/jimmun/vkae043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 12/02/2024] [Indexed: 03/14/2025]
Abstract
A gene encoding the transcription factor RTF1 has been associated with an increased risk of ulcerative colitis (UC). In this study, we investigated its function in modulating T cells expressing interleukin-17A (Th17 cells), a cardinal cell type promoting intestinal inflammation. Our results indicate that Rtf1 deficiency disrupts the differentiation of Th17 cells, while leaving regulatory T cells (Treg) unaffected. Mechanistically, RTF1 facilitates histone H2B monoubiquitination (H2Bub1), which requires its histone modification domain (HMD), for supporting Th17 cell function. Impaired Th17 differentiation was also observed in cells lacking the H2Bub1 E3 ligase subunit RNF40, an enzyme known to physically interact with RTF1. Thus, our study underscores the essential role of RTF1 in H2Bub1-mediated epigenetic regulation of Th17 cell differentiation. Understanding this process will likely provide valuable insights into addressing Th17-associated inflammatory disorders. (Images were created with BioRender).
Collapse
Affiliation(s)
| | - Guangqing Lu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
| | - Richard Gill
- Genentech, Inc, South San Francisco, CA, United States
| | - Dun Li
- Genentech, Inc, South San Francisco, CA, United States
| | - Yifang Liu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
| | - Jun R Huh
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
- Bio2Q, Keio University, Tokyo, Japan
| | - Saiyu Hang
- Genentech, Inc, South San Francisco, CA, United States
| |
Collapse
|
2
|
Liu M, Li Y, Yuan X, Rong S, Du J. Novel insights into RNA polymerase II transcription regulation: transcription factors, phase separation, and their roles in cardiovascular diseases. Biochem Cell Biol 2025; 103:1-21. [PMID: 39540550 DOI: 10.1139/bcb-2024-0094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2024] Open
Abstract
Transcription factors (TFs) are specialized proteins that bind DNA in a sequence-specific manner and modulate RNA polymerase II (Pol II) in multiple steps of the transcription process. Phase separation is a spontaneous or driven process that can form membrane-less organelles called condensates. By creating different liquid phases at active transcription sites, the formation of transcription condensates can reduce the water content of the condensate and lower the dielectric constant in biological systems, which in turn alters the structure and function of proteins and nucleic acids in the condensate. In RNA Pol II transcription, phase separation formation shortens the time at which TFs bind to target DNA sites and promotes transcriptional bursting. RNA Pol II transcription is engaged in developing several diseases, such as cardiovascular disease, by regulating different TFs and mediating the occurrence of phase separation. This review aims to summarize the advances in the molecular mechanisms of RNA Pol II transcriptional regulation, in particular the effect of TFs and phase separation. The role of RNA Pol II transcriptional regulation in cardiovascular disease will be elucidated, providing potential therapeutic targets for the management and treatment of cardiovascular disease.
Collapse
Affiliation(s)
- Mengmeng Liu
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Yingrui Li
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Xin Yuan
- Department of Nephrology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 4000l0, China
| | - Shunkang Rong
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Jianlin Du
- Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| |
Collapse
|
3
|
Francette AM, Arndt KM. Multiple direct and indirect roles of the Paf1 complex in transcription elongation, splicing, and histone modifications. Cell Rep 2024; 43:114730. [PMID: 39244754 PMCID: PMC11498942 DOI: 10.1016/j.celrep.2024.114730] [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: 03/04/2024] [Revised: 07/17/2024] [Accepted: 08/23/2024] [Indexed: 09/10/2024] Open
Abstract
The polymerase-associated factor 1 (Paf1) complex (Paf1C) is a conserved protein complex with critical functions during eukaryotic transcription. Previous studies showed that Paf1C is multi-functional, controlling specific aspects of transcription ranging from RNA polymerase II (RNAPII) processivity to histone modifications. However, it is unclear how specific Paf1C subunits directly impact transcription and coupled processes. We have compared conditional depletion to steady-state deletion for each Paf1C subunit to determine the direct and indirect contributions to gene expression in Saccharomyces cerevisiae. Using nascent transcript sequencing, RNAPII profiling, and modeling of transcription elongation dynamics, we have demonstrated direct effects of Paf1C subunits on RNAPII processivity and elongation rate and indirect effects on transcript splicing and repression of antisense transcripts. Further, our results suggest that the direct transcriptional effects of Paf1C cannot be readily assigned to any particular histone modification. This work comprehensively analyzes both the immediate and the extended roles of each Paf1C subunit in transcription elongation and transcript regulation.
Collapse
Affiliation(s)
- Alex M Francette
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| |
Collapse
|
4
|
Blanco-Touriñán N, Pérez-Alemany J, Bourbousse C, Latrasse D, Ait-Mohamed O, Benhamed M, Barneche F, Blázquez MA, Gallego-Bartolomé J, Alabadí D. The plant POLYMERASE-ASSOCIATED FACTOR1 complex links transcription and H2B monoubiquitination genome wide. PLANT PHYSIOLOGY 2024; 195:640-651. [PMID: 38285074 PMCID: PMC11060679 DOI: 10.1093/plphys/kiae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/25/2023] [Indexed: 01/30/2024]
Abstract
The evolutionarily conserved POLYMERASE-ASSOCIATED FACTOR1 complex (Paf1C) participates in transcription, and research in animals and fungi suggests that it facilitates RNA POLYMERASE II (RNAPII) progression through chromatin. We examined the genomic distribution of the EARLY FLOWERING7 (ELF7) and VERNALIZATION INDEPENDENCE3 subunits of Paf1C in Arabidopsis (Arabidopsis thaliana). The occupancy of both subunits was confined to thousands of gene bodies and positively associated with RNAPII occupancy and the level of gene expression, supporting a role as a transcription elongation factor. We found that monoubiquitinated histone H2B, which marks most transcribed genes, was strongly reduced genome wide in elf7 seedlings. Genome-wide profiling of RNAPII revealed that in elf7 mutants, RNAPII occupancy was reduced throughout the gene body and at the transcription end site of Paf1C-targeted genes, suggesting a direct role for the complex in transcription elongation. Overall, our observations suggest a direct functional link between Paf1C activity, monoubiquitination of histone H2B, and the transition of RNAPII to productive elongation. However, for several genes, Paf1C may also act independently of H2Bub deposition or occupy these genes more stable than H2Bub marking, possibly reflecting the dynamic nature of Paf1C association and H2Bub turnover during transcription.
Collapse
Affiliation(s)
- Noel Blanco-Touriñán
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), 46022 Valencia, Spain
| | - Jaime Pérez-Alemany
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), 46022 Valencia, Spain
| | - Clara Bourbousse
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (CNRS), CNRS, INSERM, Université PSL, 75230 Paris, France
| | - David Latrasse
- Institute of Plant Sciences Paris-Saclay (Université Paris-Saclay-CNRS), 91190 Gif-sur-Yvette, France
| | - Ouardia Ait-Mohamed
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (CNRS), CNRS, INSERM, Université PSL, 75230 Paris, France
| | - Moussa Benhamed
- Institute of Plant Sciences Paris-Saclay (Université Paris-Saclay-CNRS), 91190 Gif-sur-Yvette, France
| | - Fredy Barneche
- Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure (CNRS), CNRS, INSERM, Université PSL, 75230 Paris, France
| | - Miguel A Blázquez
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), 46022 Valencia, Spain
| | | | - David Alabadí
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), 46022 Valencia, Spain
| |
Collapse
|
5
|
Francette AM, Arndt KM. Multiple direct and indirect roles of Paf1C in elongation, splicing, and histone post-translational modifications. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591159. [PMID: 38712269 PMCID: PMC11071476 DOI: 10.1101/2024.04.25.591159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Paf1C is a highly conserved protein complex with critical functions during eukaryotic transcription. Previous studies have shown that Paf1C is multi-functional, controlling specific aspects of transcription, ranging from RNAPII processivity to histone modifications. However, it is unclear how specific Paf1C subunits directly impact transcription and coupled processes. We have compared conditional depletion to steady-state deletion for each Paf1C subunit to determine the direct and indirect contributions to gene expression in Saccharomyces cerevisiae. Using nascent transcript sequencing, RNAPII profiling, and modeling of transcription elongation dynamics, we have demonstrated direct effects of Paf1C subunits on RNAPII processivity and elongation rate and indirect effects on transcript splicing and repression of antisense transcripts. Further, our results suggest that the direct transcriptional effects of Paf1C cannot be readily assigned to any particular histone modification. This work comprehensively analyzes both the immediate and extended roles of each Paf1C subunit in transcription elongation and transcript regulation.
Collapse
Affiliation(s)
- Alex M. Francette
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Karen M. Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
- Lead contact
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
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: 24] [Impact Index Per Article: 12.0] [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.
Collapse
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.
| |
Collapse
|
8
|
Li C, Guo Y, Wang L, Yan S. The SMC5/6 complex recruits the PAF1 complex to facilitate DNA double-strand break repair in Arabidopsis. EMBO J 2023; 42:e112756. [PMID: 36815434 PMCID: PMC10068331 DOI: 10.15252/embj.2022112756] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023] Open
Abstract
DNA double-strand breaks (DSBs) are one of the most toxic forms of DNA damage, which threatens genome stability. Homologous recombination is an error-free DSB repair pathway, in which the evolutionarily conserved SMC5/6 complex (SMC5/6) plays essential roles. The PAF1 complex (PAF1C) is well known to regulate transcription. Here we show that SMC5/6 recruits PAF1C to facilitate DSB repair in plants. In a genetic screen for DNA damage response mutants (DDRMs), we found that the Arabidopsis ddrm4 mutant is hypersensitive to DSB-inducing agents and is defective in homologous recombination. DDRM4 encodes PAF1, a core subunit of PAF1C. Further biochemical and genetic studies reveal that SMC5/6 recruits PAF1C to DSB sites, where PAF1C further recruits the E2 ubiquitin-conjugating enzymes UBC1/2, which interact with the E3 ubiquitin ligases HUB1/2 to mediate the monoubiquitination of histone H2B at DSBs. These results implicate SMC5/6-PAF1C-UBC1/2-HUB1/2 as a new axis for DSB repair through homologous recombination, revealing a new mechanism of SMC5/6 and uncovering a novel function of PAF1C.
Collapse
Affiliation(s)
- Cunliang Li
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Yuyu Guo
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Lili Wang
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Shunping Yan
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| |
Collapse
|
9
|
Zhang J, Wang T, Bi J, Ke M, Ren Y, Wang M, Du Z, Liu W, Hu L, Zhang X, Liu X, Wang B, Wu Z, Lv Y, Meng L, Wu R. Overexpression of HSF2 binding protein suppresses endoplasmic reticulum stress via regulating subcellular localization of CDC73 in hepatocytes. Cell Biosci 2023; 13:64. [PMID: 36964632 PMCID: PMC10039577 DOI: 10.1186/s13578-023-01010-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 03/07/2023] [Indexed: 03/26/2023] Open
Abstract
BACKGROUND Endoplasmic reticulum (ER) stress plays an important role in the occurrence and development of various liver diseases. However, there are no effective prevention and treatment strategies. We aimed to determine the role of heat shock factor 2 binding protein (HSF2BP) in ER stress. METHODS HSF2BP expression in mice and cultured hepatocytes was measured during ER stress induced by tunicamycin, and its importance in ER stress was evaluated in hepatocyte-specific HSF2BP transgenic (TG) and knockout (KO) mice. The effects and mechanisms of HSF2BP on ER stress were further probed in hepatic ischemia-reperfusion (I/R) injury. RESULTS HSF2BP expression was significantly upregulated during tunicamycin-induced ER stress in mice and cultured hepatocytes. Liver injury and ER stress were reduced in HSF2BP overexpressing mice after treating with tunicamycin, but were aggravated in HSF2BP knockout mice compared to the controls. In hepatic I/R injury, HSF2BP expression was significantly upregulated, and HSF2BP overexpressing mice had reduced liver injury and inflammation. These improvements were associated with ER stress inhibition. However, these results were reversed in hepatocyte-specific HSF2BP knockout mice. HSF2BP overexpression increased cytoplasmic CDC73 levels and inhibited the JNK signaling pathway. CDC73 knockdown using siRNA eliminated the protection exerted by HSF2BP overexpression in hypoxia/reoxygenation (H/R)-induced ER stress in hepatocytes. CONCLUSION HSF2BP is a previously uncharacterized regulatory factor in ER stress-likely acts by regulating CDC73 subcellular localization. The feasibility of HSF2BP-targeted treatment in ER stress-related liver disease deserves future research.
Collapse
Affiliation(s)
- Jia Zhang
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Gastroenterology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Tao Wang
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jianbin Bi
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Mengyun Ke
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
| | - Yifan Ren
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of General Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Mengzhou Wang
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Zhaoqing Du
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Hepatobiliary Surgery, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi, China
| | - Wuming Liu
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Liangshuo Hu
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaogang Zhang
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xuemin Liu
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Bo Wang
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Zheng Wu
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Yi Lv
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China
- Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lingzhong Meng
- Anesthesiology and Perioperative Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Rongqian Wu
- National Local Joint Engineering Research Center for Precision Surgery & Regenerative Medicine, Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, Center for Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, 124, 76 West Yanta Road, Xi'an, Shaanxi, 710061, China.
| |
Collapse
|
10
|
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: 12] [Impact Index Per Article: 6.0] [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.
Collapse
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
| |
Collapse
|
11
|
Ehara H, Kujirai T, Shirouzu M, Kurumizaka H, Sekine SI. Structural basis of nucleosome disassembly and reassembly by RNAPII elongation complex with FACT. Science 2022; 377:eabp9466. [PMID: 35981082 DOI: 10.1126/science.abp9466] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During gene transcription, RNA polymerase II (RNAPII) traverses nucleosomes in chromatin, but its mechanism has remained elusive. Using cryo-electron microscopy, we obtained structures of the RNAPII elongation complex (EC) passing through a nucleosome, in the presence of transcription elongation factors Spt6, Spn1, Elf1, Spt4/5, and Paf1C and the histone chaperone FACT. The structures show snapshots of EC progression on DNA, mediating downstream nucleosome disassembly followed by its reassembly upstream of the EC, facilitated by FACT. FACT dynamically adapts to successively occurring subnucleosome intermediates, forming an interface with the EC. Spt6, Spt4/5, and Paf1C form a "cradle" at the EC DNA-exit site, and support the upstream nucleosome reassembly. These structures explain the mechanism by which the EC traverses nucleosomes while maintaining the chromatin structure and epigenetic information.
Collapse
Affiliation(s)
- Haruhiko Ehara
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomoya Kujirai
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan.,Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Hitoshi Kurumizaka
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan.,Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Shun-Ichi Sekine
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| |
Collapse
|
12
|
Eigenhuis KN, Somsen HB, van den Berg DLC. Transcription Pause and Escape in Neurodevelopmental Disorders. Front Neurosci 2022; 16:846272. [PMID: 35615272 PMCID: PMC9125161 DOI: 10.3389/fnins.2022.846272] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
Transcription pause-release is an important, highly regulated step in the control of gene expression. Modulated by various factors, it enables signal integration and fine-tuning of transcriptional responses. Mutations in regulators of pause-release have been identified in a range of neurodevelopmental disorders that have several common features affecting multiple organ systems. This review summarizes current knowledge on this novel subclass of disorders, including an overview of clinical features, mechanistic details, and insight into the relevant neurodevelopmental processes.
Collapse
|
13
|
Kubota Y, Ota N, Takatsuka H, Unno T, Onami S, Sugimoto A, Ito M. The
PAF1
complex cell‐autonomously promotes oogenesis in
Caenorhabditis elegans. Genes Cells 2022; 27:409-420. [PMID: 35430776 PMCID: PMC9321568 DOI: 10.1111/gtc.12938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/19/2022] [Accepted: 04/07/2022] [Indexed: 11/30/2022]
Abstract
The RNA polymerase II‐associated factor 1 complex (PAF1C) is a protein complex that consists of LEO1, RTF1, PAF1, CDC73, and CTR9, and has been shown to be involved in RNA polymerase II‐mediated transcriptional and chromatin regulation. Although it has been shown to regulate a variety of biological processes, the precise role of the PAF1C during germ line development has not been clarified. In this study, we found that reduction in the function of the PAF1C components, LEO‐1, RTFO‐1, PAFO‐1, CDC‐73, and CTR‐9, in Caenorhabditis elegans affects oogenesis. Defects in oogenesis were also confirmed using an oocyte maturation marker, OMA‐1::GFP. While four to five OMA‐1::GFP‐positive oocytes were observed in wild‐type animals, their numbers were significantly decreased in pafo‐1 mutant and leo‐1(RNAi), pafo‐1(RNAi), and cdc‐73(RNAi) animals. Expression of a functional PAFO‐1::mCherry transgene in the germline significantly rescued the oogenesis‐defective phenotype of the pafo‐1 mutants, suggesting that expression of the PAF1C in germ cells is required for oogenesis. Notably, overexpression of OMA‐1::GFP partially rescued the oogenesis defect in the pafo‐1 mutants. Based on our findings, we propose that the PAF1C promotes oogenesis in a cell‐autonomous manner by positively regulating the expression of genes involved in oocyte maturation.
Collapse
Affiliation(s)
- Yukihiro Kubota
- Department of Bioinformatics College of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Natsumi Ota
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Hisashi Takatsuka
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Takuma Unno
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Shuichi Onami
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
- RIKEN Center for Biosystems Dynamics Research 2‐2‐3, Minatojima‐minamimachi, Chuo‐ku Kobe Japan
| | - Asako Sugimoto
- Laboratory of Developmental Dinamics Graduate School of Life Sciences, Tohoku University 2‐1‐1 Katahira Sendai Miyagi Japan
| | - Masahiro Ito
- Department of Bioinformatics College of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| |
Collapse
|
14
|
Zhang B, Liu ZY, Wu R, Zhang CM, Cao K, Shan WG, Liu Z, Ji M, Tian ZL, Sethi G, Shi HL, Wang RH. Transcriptional regulator CTR9 promotes hepatocellular carcinoma progression and metastasis via increasing PEG10 transcriptional activity. Acta Pharmacol Sin 2021; 43:2109-2118. [PMID: 34876700 PMCID: PMC9343652 DOI: 10.1038/s41401-021-00812-3] [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: 08/02/2021] [Accepted: 10/31/2021] [Indexed: 11/09/2022]
Abstract
Cln Three Requiring 9 (CTR9), a scaffold protein of the polymerase-associated factor-1 (PAF1) complex (PAF1c), is primarily localized in the nucleus of cells. Recent studies show that CTR9 plays essential roles in the development of various human cancers and their occurrence; however, its regulatory roles and precise mechanisms in hepatocellular carcinoma (HCC) remain unclear. In this study, we investigated the roles of CTR9 using in vitro assays and a xenograft mouse model. We found that CTR9 protein is upregulated in tumor tissues from HCC patients. Knockdown of CTR9 substantially reduced HCC cell proliferation, invasion, and migration, whereas its overexpression promoted these activities. In addition, in vitro results revealed that CTR9 silencing dramatically increased cell cycle regulators, p21 and p27, but markedly decreased matrix metalloproteinases, MMP2 and MMP9, with these outcomes reversed upon CTR9 overexpression. Furthermore, the underlying molecular mechanism suggests that CTR9 promoted the oncogene paternally expressed gene 10 (PEG10) transcription via its promoter region. Finally, the oncogenic roles of CTR9 were confirmed in a xenograft mouse model. This study confirms that CTR9, an oncoprotein that promotes HCC cell proliferation, invasion, and migration, increases tumor growth in a xenograft mouse model. CTR9 could be a novel therapeutic target. Further investigation is warranted to verify CTR9 potential in novel therapies for HCC.
Collapse
|
15
|
Chen F, Liu B, Zeng J, Guo L, Ge X, Feng W, Li DF, Zhou H, Long J. Crystal Structure of the Core Module of the Yeast Paf1 Complex. J Mol Biol 2021; 434:167369. [PMID: 34852272 DOI: 10.1016/j.jmb.2021.167369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/31/2022]
Abstract
The highly conserved multifunctional polymerase-associated factor 1 (Paf1) complex (PAF1C), which consists of five core subunits: Ctr9, Paf1, Leo1, Cdc73, and Rtf1, acts as a diverse hub that regulates all stages of RNA polymerase II-mediated transcription and various other cellular functions. However, the underlying mechanisms remain unclear. Here, we report the crystal structure of the core module derived from a quaternary Ctr9/Paf1/Cdc73/Rtf1 complex of S. cerevisiae PAF1C, which reveals interfaces between the tetratricopeptide repeat module in Ctr9 and Cdc73 or Rtf1, and find that the Ctr9/Paf1 subcomplex is the key scaffold for PAF1C assembly. Our study demonstrates that Cdc73 binds Ctr9/Paf1 subcomplex with a very similar conformation within thermophilic fungi or human PAF1C, and that the binding of Cdc73 to PAF1C is important for yeast growth. Importantly, our structure reveals for the first time that the extreme C-terminus of Rtf1 adopts an "L"-shaped structure, which interacts with Ctr9 specifically. In addition, disruption of the binding of either Cdc73 or Rtf1 to PAF1C greatly affects the normal level of histone H2B K123 monoubiquitination in vivo. Collectively, our results provide a structural insight into the architecture of the quaternary Ctr9/Paf1/Cdc73/Rtf1 complex and PAF1C functional regulation.
Collapse
Affiliation(s)
- Feilong Chen
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Beibei Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Jianwei Zeng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lu Guo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuan Ge
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - De-Feng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Hao Zhou
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
| | - Jiafu Long
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China; Nankai International Advanced Research Institute (Shenzhen Futian), Shenzhen, Guangdong 518045, China.
| |
Collapse
|
16
|
Francette AM, Tripplehorn SA, Arndt KM. The Paf1 Complex: A Keystone of Nuclear Regulation Operating at the Interface of Transcription and Chromatin. J Mol Biol 2021; 433:166979. [PMID: 33811920 PMCID: PMC8184591 DOI: 10.1016/j.jmb.2021.166979] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
The regulation of transcription by RNA polymerase II is closely intertwined with the regulation of chromatin structure. A host of proteins required for the disassembly, reassembly, and modification of nucleosomes interacts with Pol II to aid its movement and counteract its disruptive effects on chromatin. The highly conserved Polymerase Associated Factor 1 Complex, Paf1C, travels with Pol II and exerts control over transcription elongation and chromatin structure, while broadly impacting the transcriptome in both single cell and multicellular eukaryotes. Recent studies have yielded exciting new insights into the mechanisms by which Paf1C regulates transcription elongation, epigenetic modifications, and post-transcriptional steps in eukaryotic gene expression. Importantly, these functional studies are now supported by an extensive foundation of high-resolution structural information, providing intimate views of Paf1C and its integration into the larger Pol II elongation complex. As a global regulatory factor operating at the interface between chromatin and transcription, the impact of Paf1C is broad and its influence reverberates into other domains of nuclear regulation, including genome stability, telomere maintenance, and DNA replication.
Collapse
Affiliation(s)
- Alex M Francette
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Sarah A Tripplehorn
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States.
| |
Collapse
|
17
|
Cucinotta CE, Hildreth AE, McShane BM, Shirra MK, Arndt KM. The nucleosome acidic patch directly interacts with subunits of the Paf1 and FACT complexes and controls chromatin architecture in vivo. Nucleic Acids Res 2019; 47:8410-8423. [PMID: 31226204 PMCID: PMC6895269 DOI: 10.1093/nar/gkz549] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/12/2022] Open
Abstract
The nucleosome core regulates DNA-templated processes through the highly conserved nucleosome acidic patch. While structural and biochemical studies have shown that the acidic patch controls chromatin factor binding and activity, few studies have elucidated its functions in vivo. We employed site-specific crosslinking to identify proteins that directly bind the acidic patch in Saccharomyces cerevisiae and demonstrated crosslinking of histone H2A to Paf1 complex subunit Rtf1 and FACT subunit Spt16. Rtf1 bound to nucleosomes through its histone modification domain, supporting its role as a cofactor in H2B K123 ubiquitylation. An acidic patch mutant showed defects in nucleosome positioning and occupancy genome-wide. Our results provide new information on the chromatin engagement of two central players in transcription elongation and emphasize the importance of the nucleosome core as a hub for proteins that regulate chromatin during transcription.
Collapse
Affiliation(s)
- Christine E Cucinotta
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - A Elizabeth Hildreth
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Brendan M McShane
- 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
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| |
Collapse
|
18
|
Zhou FL, Li SC, Zhu Y, Guo WJ, Shao LJ, Nelson J, Simpkins S, Yang DH, Liu Q, Yashiroda Y, Xu JB, Fan YY, Yue JM, Yoshida M, Xia T, Myers CL, Boone C, Wang MW. Integrating yeast chemical genomics and mammalian cell pathway analysis. Acta Pharmacol Sin 2019; 40:1245-1255. [PMID: 31138898 PMCID: PMC6786357 DOI: 10.1038/s41401-019-0231-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/14/2019] [Indexed: 12/27/2022]
Abstract
Chemical genomics has been applied extensively to evaluate small molecules that modulate biological processes in Saccharomyces cerevisiae. Here, we use yeast as a surrogate system for studying compounds that are active against metazoan targets. Large-scale chemical-genetic profiling of thousands of synthetic and natural compounds from the Chinese National Compound Library identified those with high-confidence bioprocess target predictions. To discover compounds that have the potential to function like therapeutic agents with known targets, we also analyzed a reference library of approved drugs. Previously uncharacterized compounds with chemical-genetic profiles resembling existing drugs that modulate autophagy and Wnt/β-catenin signal transduction were further examined in mammalian cells, and new modulators with specific modes of action were validated. This analysis exploits yeast as a general platform for predicting compound bioactivity in mammalian cells.
Collapse
Affiliation(s)
- Fu-Lai Zhou
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sheena C Li
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, 3510198, Japan
| | - Yue Zhu
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wan-Jing Guo
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li-Jun Shao
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Justin Nelson
- Bioinformatics and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota, 55455, USA
| | - Scott Simpkins
- Bioinformatics and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota, 55455, USA
| | - De-Hua Yang
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
| | - Qing Liu
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China
| | - Yoko Yashiroda
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, 3510198, Japan
| | - Jin-Biao Xu
- The State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Yao-Yue Fan
- The State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Jian-Min Yue
- The State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Minoru Yoshida
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, 3510198, Japan
- Department of Biology, The University of Tokyo, Bunkyo-ku, Tokyo, 1138657, Japan
- Collaborative Research for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, 1138657, Japan
| | - Tian Xia
- Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chad L Myers
- Bioinformatics and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota, 55455, USA.
| | - Charles Boone
- RIKEN Center for Sustainable Resource Science, Wako, Saitama, 3510198, Japan.
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Ontario, M5S 3E1, Canada.
| | - Ming-Wei Wang
- The National Center for Drug Screening and the CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| |
Collapse
|
19
|
Heuberger J, Hill U, Förster S, Zimmermann K, Malchin V, Kühl AA, Stein U, Vieth M, Birchmeier W, Leutz A. A C/EBPα-Wnt connection in gut homeostasis and carcinogenesis. Life Sci Alliance 2018; 2:e201800173. [PMID: 30599048 PMCID: PMC6306571 DOI: 10.26508/lsa.201800173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022] Open
Abstract
This research reveals an antagonism between C/EBPα expression and activated Wnt signaling in the human and mouse gut and suggests a tumor suppressor function of C/EBPα in human and murine intestinal cancer. We explored the connection between C/EBPα (CCAAT/enhancer-binding protein α) and Wnt signaling in gut homeostasis and carcinogenesis. C/EBPα was expressed in human and murine intestinal epithelia in the transit-amplifying region of the crypts and was absent in intestinal stem cells and Paneth cells with activated Wnt signaling. In human colorectal cancer and murine APCMin/+ polyps, C/EBPα was absent in the nuclear β-catenin–positive tumor cells. In chemically induced intestinal carcinogenesis, C/EBPα KO in murine gut epithelia increased tumor volume. C/EBPα deletion extended the S-phase cell zone in intestinal organoids and activated typical proliferation gene expression signatures, including that of Wnt target genes. Genetic activation of β-catenin in organoids attenuated C/EBPα expression, and ectopic C/EBPα expression in HCT116 cells abrogated proliferation. C/EBPα expression accompanied differentiation of the colon cancer cell line Caco-2, whereas β-catenin stabilization suppressed C/EBPα. These data suggest homeostatic and oncogenic suppressor functions of C/EBPα in the gut by restricting Wnt signaling.
Collapse
Affiliation(s)
| | - Undine Hill
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Susann Förster
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | | | - Anja A Kühl
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ulrike Stein
- Experimental and Clinical Research Center, Charite-Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine, Berlin, Germany.,German Cancer Consortium (Deutsches Konsortium für Translationale Krebsforschung), Heidelberg, Germany
| | - Michael Vieth
- Klinikum Bayreuth, Institute for Pathology, Bayreuth, Germany
| | | | - Achim Leutz
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.,Institute of Biology, Humboldt University of Berlin, Berlin, Germany
| |
Collapse
|
20
|
Abstract
Regulation of plant root angle is critical for obtaining nutrients and water and is an important trait for plant breeding. A plant’s final, long-term root angle is the net result of a complex series of decisions made by a root tip in response to changes in nutrient availability, impediments, the gravity vector and other stimuli. When a root tip is displaced from the gravity vector, the short-term process of gravitropism results in rapid reorientation of the root toward the vertical. Here, we explore both short- and long-term regulation of root growth angle, using natural variation in tomato to identify shared and separate genetic features of the two responses. Mapping of expression quantitative trait loci mapping and leveraging natural variation between and within species including Arabidopsis suggest a role for PURPLE ACID PHOSPHATASE 27 and CELL DIVISION CYCLE 73 in determining root angle.
Collapse
|
21
|
Cooper KF, STRICH RANDY. Functional analysis of the Ume3p/ Srb11p-RNA polymerase II holoenzyme interaction. Gene Expr 2018; 8:43-57. [PMID: 10543730 PMCID: PMC6157353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The yeast C-type cyclin Ume3p/Srb11p and its cyclin-dependent kinase (Cdk) Ume5p are required for the full repression of genes involved in the stress response or meiosis. This cyclin-Cdk kinase copurifies with the RNA polymerase II holoenzyme complex, suggesting it functions through modification of the transcriptional machinery. This report describes two domains required for Ume3p-RNA Pol II holoenzyme association. One domain contains the highly conserved cyclin box that directs cyclin-Cdk interaction and requires Ume5p for holoenzyme binding. The second domain, termed HAD for holoenzyme associating domain, is located within the amino-terminal region of the cyclin and is sufficient for holoenzyme binding independent of Ume5p or the cyclin box. In addition to its role in RNA Pol II holoenzyme association, the HAD is also required for Ume3p-dependent repression in vivo. Finally, HAD mutations do not affect the ability of the Ume3p-Ume5p kinase to phosphorylate in vitro the carboxy-terminal domain (CTD) of RNA polymerase II, a reported target of cyclin C-Cdk activity. In conclusion, this study demonstrates that the association of the Ume3p to the holoenzyme is complex, involving two independent domains, both of which are required for full Ume3p-dependent repression in vivo. Furthermore, HAD-dependent repression does not appear to involve CTD phosphorylation, suggesting a different role for this domain in directing Ume3p-Ume5p activity.
Collapse
Affiliation(s)
- Katrina F. Cooper
- Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Ave., Philadelphia, PA 19111
| | - RANDY STRICH
- Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Ave., Philadelphia, PA 19111
- Address correspondence to Randy Strich, Institute for Cancer Research, Fox Chase Cancer Center, 7701 Burholme Ave., Philadelphia, PA 19111. Tel: (215) 728-5321; Fax: (215) 728-3616; E-mail
| |
Collapse
|
22
|
Ropa J, Saha N, Chen Z, Serio J, Chen W, Mellacheruvu D, Zhao L, Basrur V, Nesvizhskii AI, Muntean AG. PAF1 complex interactions with SETDB1 mediate promoter H3K9 methylation and transcriptional repression of Hoxa9 and Meis1 in acute myeloid leukemia. Oncotarget 2018; 9:22123-22136. [PMID: 29774127 PMCID: PMC5955148 DOI: 10.18632/oncotarget.25204] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/04/2018] [Indexed: 12/30/2022] Open
Abstract
The Polymerase Associated Factor 1 complex (PAF1c) is an epigenetic co-modifying complex that directly contacts RNA polymerase II (RNAPII) and several epigenetic regulating proteins. Mutations, overexpression and loss of expression of subunits of the PAF1c are observed in various forms of cancer suggesting proper regulation is needed for cellular development. However, the biochemical interactions with the PAF1c that allow dynamic gene regulation are unclear. We and others have shown that the PAF1c makes a direct interaction with MLL fusion proteins, which are potent oncogenic drivers of acute myeloid leukemia (AML). This interaction is critical for the maintenance of MLL translocation driven AML by targeting MLL fusion proteins to the target genes Meis1 and Hoxa9. Here, we use a proteomics approach to identify protein-protein interactions with the PAF1c subunit CDC73 that regulate the function of the PAF1c. We identified a novel interaction with a histone H3 lysine 9 (H3K9) methyltransferase protein, SETDB1. This interaction is stabilized with a mutant CDC73 that is incapable of supporting AML cell growth. Importantly, transcription of Meis1 and Hoxa9 is reduced and promoter H3K9 trimethylation (H3K9me3) increased by overexpression of SETDB1 or stabilization of the PAF1c-SETDB1 interaction in AML cells. These findings were corroborated in human AML patients where increased SETDB1 expression was associated with reduced HOXA9 and MEIS1. To our knowledge, this is the first proteomics approach to search for CDC73 protein-protein interactions in AML, and demonstrates that the PAF1c may play a role in H3K9me3-mediated transcriptional repression in AML.
Collapse
Affiliation(s)
- James Ropa
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Nirmalya Saha
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Zhiling Chen
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Justin Serio
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Wei Chen
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Dattatreya Mellacheruvu
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Lili Zhao
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Venkatesha Basrur
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alexey I. Nesvizhskii
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Andrew G. Muntean
- Department of Pathology and The University of Michigan Medical School, Ann Arbor, Michigan, USA
| |
Collapse
|
23
|
Cdc73 suppresses genome instability by mediating telomere homeostasis. PLoS Genet 2018; 14:e1007170. [PMID: 29320491 PMCID: PMC5779705 DOI: 10.1371/journal.pgen.1007170] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 01/23/2018] [Accepted: 12/25/2017] [Indexed: 12/18/2022] Open
Abstract
Defects in the genes encoding the Paf1 complex can cause increased genome instability. Loss of Paf1, Cdc73, and Ctr9, but not Rtf1 or Leo1, caused increased accumulation of gross chromosomal rearrangements (GCRs). Combining the cdc73Δ mutation with individual deletions of 43 other genes, including TEL1 and YKU80, which are involved in telomere maintenance, resulted in synergistic increases in GCR rates. Whole genome sequence analysis of GCRs indicated that there were reduced relative rates of GCRs mediated by de novo telomere additions and increased rates of translocations and inverted duplications in cdc73Δ single and double mutants. Analysis of telomere lengths and telomeric gene silencing in strains containing different combinations of cdc73Δ, tel1Δ and yku80Δ mutations suggested that combinations of these mutations caused increased defects in telomere maintenance. A deletion analysis of Cdc73 revealed that a central 105 amino acid region was necessary and sufficient for suppressing the defects observed in cdc73Δ strains; this region was required for the binding of Cdc73 to the Paf1 complex through Ctr9 and for nuclear localization of Cdc73. Taken together, these data suggest that the increased GCR rate of cdc73Δ single and double mutants is due to partial telomere dysfunction and that Ctr9 and Paf1 play a central role in the Paf1 complex potentially by scaffolding the Paf1 complex subunits or by mediating recruitment of the Paf1 complex to the different processes it functions in. Maintaining a stable genome is crucial for all organisms, and loss of genome stability has been linked to multiple human diseases, including many cancers. Previously we found that defects in Cdc73, a component of the Paf1 transcriptional elongation complex, give rise to increased genome instability. Here, we explored the mechanism underlying this instability and found that Cdc73 defects give rise to partial defects in maintaining telomeres, which are the specialized ends of chromosomes, and interact with other mutations causing telomere defects. Remarkably, Cdc73 function is mediated through a short central region of the protein that is not a part of previously identified protein domains but targets Cdc73 to the Paf1 complex through interaction with the Ctr9 subunit. Analysis of the other components of the Paf1 complex provides a model in which the Paf1 subunit mediates recruitment of the other subunits to different processes they function in. Together, these data suggest that the mutations in CDC73 and CTR9 found in patients with hyperparathyroidism-jaw tumor syndrome and some patients with Wilms tumors, respectively, may contribute to cancer progression by contributing to genome instability.
Collapse
|
24
|
Gates LA, Foulds CE, O'Malley BW. Histone Marks in the 'Driver's Seat': Functional Roles in Steering the Transcription Cycle. Trends Biochem Sci 2017; 42:977-989. [PMID: 29122461 DOI: 10.1016/j.tibs.2017.10.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022]
Abstract
Particular chromatin modifications are associated with different states of gene transcription, yet our understanding of which modifications are causal 'drivers' in promoting transcription is incomplete. Here, we discuss new developments describing the ordered, mechanistic role of select histone marks occurring during distinct steps in the RNA polymerase II (Pol II) transcription cycle. In particular, we highlight the interplay between histone marks in specifying the 'next step' of transcription. While many studies have described correlative relationships between histone marks and their occupancy at distinct gene regions, we focus on studies that elucidate clear functional consequences of specific histone marks during different stages of transcription. These recent discoveries have refined our current mechanistic understanding of how histone marks promote Pol II transcriptional progression.
Collapse
Affiliation(s)
- Leah A Gates
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA; Current address: Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY, USA
| | - Charles E Foulds
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA; Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, USA
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
25
|
Ferdoush J, Karmakar S, Barman P, Kaja A, Uprety B, Batra SK, Bhaumik SR. Ubiquitin–Proteasome System Regulation of an Evolutionarily Conserved RNA Polymerase II-Associated Factor 1 Involved in Pancreatic Oncogenesis. Biochemistry 2017; 56:6083-6086. [PMID: 29023102 DOI: 10.1021/acs.biochem.7b00865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The evolutionarily conserved RNA polymerase II-associated factor 1 (Paf1) from yeast to humans regulates transcription and associated processes, and thus, malfunctions and/or misregulations of Paf1 are associated with cellular pathologies. Indeed, Paf1 (also known as PD2 or pancreatic differentiation 2) is found to be upregulated in poorly differentiated cancer cells, and such upregulation is involved in cellular transformation or oncogenesis. However, the basis for Paf1 upregulation in these cells remains largely unknown. In light of this, we have tested here the idea that the ubiquitin-proteasome system (UPS) regulates the cellular abundance of Paf1. In this direction, we analyzed the role of UPS in regulation of Paf1's abundance in yeast. We find that Paf1 undergoes ubiquitylation and is degraded by the 26S proteasome in yeast, thus deciphering UPS regulation of an evolutionarily conserved factor, Paf1, involved in various cellular processes at the crossroads of the cancer networks. Likewise, Paf1 undergoes proteasomal degradation in well-differentiated, but not poorly differentiated, pancreatic cancer cells, hence pointing to the UPS in upregulation of Paf1 in poorly differentiated cancers. Collectively, our results reveal UPS regulation of Paf1 and suggest downregulation of UPS in elevating Paf1's abundance in poorly differentiated cancers.
Collapse
Affiliation(s)
- Jannatul Ferdoush
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Saswati Karmakar
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Priyanka Barman
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Amala Kaja
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Bhawana Uprety
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Surinder K. Batra
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Sukesh R. Bhaumik
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| |
Collapse
|
26
|
Van Oss SB, Cucinotta CE, Arndt KM. Emerging Insights into the Roles of the Paf1 Complex in Gene Regulation. Trends Biochem Sci 2017; 42:788-798. [PMID: 28870425 PMCID: PMC5658044 DOI: 10.1016/j.tibs.2017.08.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022]
Abstract
The conserved, multifunctional Polymerase-Associated Factor 1 complex (Paf1C) regulates all stages of the RNA polymerase (Pol) II transcription cycle. In this review, we examine a diverse set of recent studies from various organisms that build on foundational studies in budding yeast. These studies identify new roles for Paf1C in the control of gene expression and the regulation of chromatin structure. In exploring these advances, we find that various functions of Paf1C, such as the regulation of promoter-proximal pausing and development in higher eukaryotes, are complex and context dependent. As more becomes known about the role of Paf1C in human disease, interest in the molecular mechanisms underpinning Paf1C function will continue to increase.
Collapse
Affiliation(s)
- S Branden Van Oss
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Christine E Cucinotta
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| |
Collapse
|
27
|
Xu Y, Bernecky C, Lee CT, Maier KC, Schwalb B, Tegunov D, Plitzko JM, Urlaub H, Cramer P. Architecture of the RNA polymerase II-Paf1C-TFIIS transcription elongation complex. Nat Commun 2017; 8:15741. [PMID: 28585565 PMCID: PMC5467213 DOI: 10.1038/ncomms15741] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 04/25/2017] [Indexed: 02/01/2023] Open
Abstract
The conserved polymerase-associated factor 1 complex (Paf1C) plays multiple roles in chromatin transcription and genomic regulation. Paf1C comprises the five subunits Paf1, Leo1, Ctr9, Cdc73 and Rtf1, and binds to the RNA polymerase II (Pol II) transcription elongation complex (EC). Here we report the reconstitution of Paf1C from Saccharomyces cerevisiae, and a structural analysis of Paf1C bound to a Pol II EC containing the elongation factor TFIIS. Cryo-electron microscopy and crosslinking data reveal that Paf1C is highly mobile and extends over the outer Pol II surface from the Rpb2 to the Rpb3 subunit. The Paf1-Leo1 heterodimer and Cdc73 form opposite ends of Paf1C, whereas Ctr9 bridges between them. Consistent with the structural observations, the initiation factor TFIIF impairs Paf1C binding to Pol II, whereas the elongation factor TFIIS enhances it. We further show that Paf1C is globally required for normal mRNA transcription in yeast. These results provide a three-dimensional framework for further analysis of Paf1C function in transcription through chromatin.
Collapse
Affiliation(s)
- Youwei Xu
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| | - Carrie Bernecky
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| | - Chung-Tien Lee
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Robert-Koch-Strasse 40, Göttingen 37075, Germany
| | - Kerstin C Maier
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| | - Dimitry Tegunov
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, Martinsried 82152, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center, Göttingen, Robert-Koch-Strasse 40, Göttingen 37075, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Max Planck Society, Am Fassberg 11, Göttingen 37077, Germany
| |
Collapse
|
28
|
Zhang Y, Najmi SM, Schneider DA. Transcription factors that influence RNA polymerases I and II: To what extent is mechanism of action conserved? BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:246-255. [PMID: 27989933 DOI: 10.1016/j.bbagrm.2016.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/07/2016] [Accepted: 10/25/2016] [Indexed: 01/05/2023]
Abstract
In eukaryotic cells, nuclear RNA synthesis is accomplished by at least three unique, multisubunit RNA polymerases. The roles of these enzymes are generally partitioned into the synthesis of the three major classes of RNA: rRNA, mRNA, and tRNA for RNA polymerases I, II, and III respectively. Consistent with their unique cellular roles, each enzyme has a complement of specialized transcription factors and enzymatic properties. However, not all transcription factors have evolved to affect only one eukaryotic RNA polymerase. In fact, many factors have been shown to influence the activities of multiple nuclear RNA polymerases. This review focuses on a subset of these factors, specifically addressing the mechanisms by which these proteins influence RNA polymerases I and II.
Collapse
Affiliation(s)
- Yinfeng Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Saman M Najmi
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294
| |
Collapse
|
29
|
Ctr9, a Key Component of the Paf1 Complex, Affects Proliferation and Terminal Differentiation in the Developing Drosophila Nervous System. G3-GENES GENOMES GENETICS 2016; 6:3229-3239. [PMID: 27520958 PMCID: PMC5068944 DOI: 10.1534/g3.116.034231] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Paf1 protein complex (Paf1C) is increasingly recognized as a highly conserved and broadly utilized regulator of a variety of transcriptional processes. These include the promotion of H3K4 and H3K36 trimethylation, H2BK123 ubiquitination, RNA Pol II transcriptional termination, and also RNA-mediated gene silencing. Paf1C contains five canonical protein components, including Paf1 and Ctr9, which are critical for overall complex integrity, as well as Rtf1, Leo1, and Cdc73/Parafibromin(Hrpt2)/Hyrax. In spite of a growing appreciation for the importance of Paf1C from yeast and mammalian studies, there has only been limited work in Drosophila. Here, we provide the first detailed phenotypic study of Ctr9 function in Drosophila. We found that Ctr9 mutants die at late embryogenesis or early larval life, but can be partly rescued by nervous system reexpression of Ctr9. We observed a number of phenotypes in Ctr9 mutants, including increased neuroblast numbers, increased nervous system proliferation, as well as downregulation of many neuropeptide genes. Analysis of cell cycle and regulatory gene expression revealed upregulation of the E2f1 cell cycle factor, as well as changes in Antennapedia and Grainy head expression. We also found reduction of H3K4me3 modification in the embryonic nervous system. Genome-wide transcriptome analysis points to additional downstream genes that may underlie these Ctr9 phenotypes, revealing gene expression changes in Notch pathway target genes, cell cycle genes, and neuropeptide genes. In addition, we find significant effects on the gene expression of metabolic genes. These findings reveal that Ctr9 is an essential gene that is necessary at multiple stages of nervous system development, and provides a starting point for future studies of the Paf1C in Drosophila.
Collapse
|
30
|
Dephosphorylated parafibromin is a transcriptional coactivator of the Wnt/Hedgehog/Notch pathways. Nat Commun 2016; 7:12887. [PMID: 27650679 PMCID: PMC5036006 DOI: 10.1038/ncomms12887] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 08/11/2016] [Indexed: 01/20/2023] Open
Abstract
Evolutionally conserved Wnt, Hedgehog (Hh) and Notch morphogen pathways play essential roles in the development, homeostasis and pathogenesis of multicellular organisms. Nevertheless, mechanisms that intracellularly coordinate these signal inputs remain poorly understood. Here we found that parafibromin, a component of the PAF complex, competitively interacts with β-catenin and Gli1, thereby potentiating transactivation of Wnt- and Hh-target genes in a mutually exclusive manner. Parafibromin also binds to the Notch intracellular domain (NICD), enabling concerted activation of Wnt- and Notch-target genes. The transcriptional platform function of parafibromin is potentiated by tyrosine dephosphorylation, mediated by SHP2 phosphatase, while it is attenuated by tyrosine phosphorylation, mediated by PTK6 kinase. Consequently, acute loss of parafibromin in mice disorganizes the normal epithelial architecture of the intestine, which requires coordinated activation/inactivation of Wnt, Hh and/or Notch signalling. Parafibromin integrates and converts signals conveyed by these morphogen pathways into appropriate transcriptional outputs in a tyrosine phosphorylation/dephosphorylation-regulated manner. Normal epithelial intestine organisation requires Wnt and Hedgehog signalling activity. Here, the authors show that parafibromin can activate both pathways in a mutually exclusive manner and is important for intestinal homeostasis.
Collapse
|
31
|
Bedard LG, Dronamraju R, Kerschner JL, Hunter GO, Axley ED, Boyd AK, Strahl BD, Mosley AL. Quantitative Analysis of Dynamic Protein Interactions during Transcription Reveals a Role for Casein Kinase II in Polymerase-associated Factor (PAF) Complex Phosphorylation and Regulation of Histone H2B Monoubiquitylation. J Biol Chem 2016; 291:13410-20. [PMID: 27143358 DOI: 10.1074/jbc.m116.727735] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 11/06/2022] Open
Abstract
Using affinity purification MS approaches, we have identified a novel role for casein kinase II (CKII) in the modification of the polymerase associated factor complex (PAF-C). Our data indicate that the facilitates chromatin transcription complex (FACT) interacts with CKII and may facilitate PAF complex phosphorylation. Posttranslational modification analysis of affinity-isolated PAF-C shows extensive CKII phosphorylation of all five subunits of PAF-C, although CKII subunits were not detected as interacting partners. Consistent with this, recombinant CKII or FACT-associated CKII isolated from cells can phosphorylate PAF-C in vitro, whereas no intrinsic kinase activity was detected in PAF-C samples. Significantly, PAF-C purifications combined with stable isotope labeling in cells (SILAC) quantitation for PAF-C phosphorylation from wild-type and CKII temperature-sensitive strains (cka1Δ cka2-8) showed that PAF-C phosphorylation at consensus CKII sites is significantly reduced in cka1Δ cka2-8 strains. Consistent with a role of CKII in FACT and PAF-C function, we show that decreased CKII function in vivo results in decreased levels of histone H2B lysine 123 monoubiquitylation, a modification dependent on FACT and PAF-C. Taken together, our results define a coordinated role of CKII and FACT in the regulation of RNA polymerase II transcription through chromatin via phosphorylation of PAF-C.
Collapse
Affiliation(s)
- Lynn Glowczewski Bedard
- From the Department of Biology, DePauw University, Greencastle, Indiana 46135, the Department of Biochemistry and Molecular Biology and
| | | | - Jenny L Kerschner
- the Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, and
| | | | | | - Asha K Boyd
- From the Department of Biology, DePauw University, Greencastle, Indiana 46135, the Department of Biochemistry and Molecular Biology and
| | - Brian D Strahl
- the Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, and Curriculum in Genetics and Molecular Biology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Amber L Mosley
- the Department of Biochemistry and Molecular Biology and Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana 46202, and
| |
Collapse
|
32
|
Characterization of the Human Transcription Elongation Factor Rtf1: Evidence for Nonoverlapping Functions of Rtf1 and the Paf1 Complex. Mol Cell Biol 2015. [PMID: 26217014 DOI: 10.1128/mcb.00601-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Restores TBP function 1 (Rtf1) is generally considered to be a subunit of the Paf1 complex (PAF1C), a multifunctional protein complex involved in histone modification and transcriptional or posttranscriptional regulation. Rtf1, however, is not stably associated with the PAF1C in most species except Saccharomyces cerevisiae, and its biochemical functions are not well understood. Here, we show that human Rtf1 is a transcription elongation factor that may function independently of the PAF1C. Rtf1 requires "Rtf1 coactivator" activity, which is most likely unrelated to the PAF1C or DSIF, for transcriptional activation in vitro. A mutational study revealed that the Plus3 domain of human Rtf1 is critical for its coactivator-dependent function. Transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation studies in HeLa cells showed that Rtf1 and the PAF1C play distinct roles in regulating the expression of a subset of genes. Moreover, contrary to the finding in S. cerevisiae, the PAF1C was apparently recruited to the genes examined in an Rtf1-independent manner. The present study establishes a role for human Rtf1 as a transcription elongation factor and highlights the similarities and differences between the S. cerevisiae and human Rtf1 proteins.
Collapse
|
33
|
Braun KA, Vaga S, Dombek KM, Fang F, Palmisano S, Aebersold R, Young ET. Phosphoproteomic analysis identifies proteins involved in transcription-coupled mRNA decay as targets of Snf1 signaling. Sci Signal 2014; 7:ra64. [PMID: 25005228 DOI: 10.1126/scisignal.2005000] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Stresses, such as glucose depletion, activate Snf1, the Saccharomyces cerevisiae ortholog of adenosine monophosphate-activated protein kinase (AMPK), enabling adaptive cellular responses. In addition to affecting transcription, Snf1 may also promote mRNA stability in a gene-specific manner. To understand Snf1-mediated signaling, we used quantitative mass spectrometry to identify proteins that were phosphorylated in a Snf1-dependent manner. We identified 210 Snf1-dependent phosphopeptides in 145 proteins. Thirteen of these proteins are involved in mRNA metabolism. Of these, we found that Ccr4 (the major cytoplasmic deadenylase), Dhh1 (an RNA helicase), and Xrn1 (an exoribonuclease) were required for the glucose-induced decay of Snf1-dependent mRNAs that were activated by glucose depletion. Unexpectedly, deletion of XRN1 reduced the accumulation of Snf1-dependent transcripts that were synthesized during glucose depletion. Deletion of SNF1 rescued the synthetic lethality of simultaneous deletion of XRN1 and REG1, which encodes a regulatory subunit of a phosphatase that inhibits Snf1. Mutation of three Snf1-dependent phosphorylation sites in Xrn1 reduced glucose-induced mRNA decay. Thus, Xrn1 is required for Snf1-dependent mRNA homeostasis in response to nutrient availability.
Collapse
Affiliation(s)
- Katherine A Braun
- Department of Biochemistry, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195-7350, USA
| | - Stefania Vaga
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, CH-8057 Zurich, Switzerland
| | - Kenneth M Dombek
- Department of Biochemistry, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195-7350, USA
| | - Fang Fang
- Department of Biochemistry, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195-7350, USA
| | - Salvator Palmisano
- Department of Biochemistry, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195-7350, USA
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, CH-8057 Zurich, Switzerland. Faculty of Science, University of Zurich, CH-8057 Zurich, Switzerland
| | - Elton T Young
- Department of Biochemistry, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195-7350, USA.
| |
Collapse
|
34
|
The PAF1 complex is involved in embryonic epidermal morphogenesis in Caenorhabditis elegans. Dev Biol 2014; 391:43-53. [PMID: 24721716 DOI: 10.1016/j.ydbio.2014.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 03/29/2014] [Accepted: 04/02/2014] [Indexed: 11/21/2022]
Abstract
The PAF1 complex (PAF1C) is an evolutionarily conserved protein complex involved in transcriptional regulation and chromatin remodeling. How the PAF1C is involved in animal development is still not well understood. Here, we report that, in the nematode Caenorhabditis elegans, the PAF1C is involved in epidermal morphogenesis in late embryogenesis. From an RNAi screen we identified the C. elegans ortholog of a component of the PAF1C, CTR-9, as a gene whose depletion caused various defects during embryonic epidermal morphogenesis, including epidermal cell positioning, ventral enclosure and epidermal elongation. RNAi of orthologs of other four components of the PAF1C (PAFO-1, LEO-1, CDC-73 and RTFO-1) caused similar epidermal defects. In these embryos, whereas the number and cell fate determination of epidermal cells were apparently unaffected, their position and shape were severely disorganized. PAFO-1::mCherry, mCherry::LEO-1 and GFP::RTFO-1 driven by the authentic promoters were detected in the nuclei of a wide range of cells. Nuclear localization of GFP::RTFO-1 was independent of other PAF1C components, while PAFO-1::mCherry and mCherry::LEO-1 dependent on other components except RTFO-1. Epidermis-specific expression of mCherry::LEO-1 rescued embryonic lethality of the leo-1 deletion mutant. Thus, although the PAF1C is universally expressed in C. elegans embryos, its epidermal function is crucial for the viability of this animal.
Collapse
|
35
|
The recruitment of the Saccharomyces cerevisiae Paf1 complex to active genes requires a domain of Rtf1 that directly interacts with the Spt4-Spt5 complex. Mol Cell Biol 2013; 33:3259-73. [PMID: 23775116 DOI: 10.1128/mcb.00270-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription elongation factors associate with RNA polymerase II and aid its translocation through chromatin. One such factor is the conserved Paf1 complex (Paf1C), which regulates gene expression through several mechanisms, including the stimulation of cotranscriptional histone modifications. Previous studies revealed a prominent role for the Rtf1 subunit in tethering Paf1C to the RNA polymerase II elongation machinery. Here, we investigated the mechanism by which Rtf1 couples Paf1C to active chromatin. We show that a highly conserved domain of Rtf1 is necessary and sufficient for mediating a physical interaction between Rtf1 and the essential transcription elongation factor Spt5. Mutations that alter this Rtf1 domain or delete the Spt5 C-terminal repeat domain (CTR) disrupt the interaction between Rtf1 and Spt5 and release Paf1C from chromatin. When expressed in cells as the only source of Rtf1, the Spt5-interacting domain of Rtf1 can associate independently with active genes in a pattern similar to that of full-length Rtf1 and in a manner dependent on the Spt5 CTR. In vitro experiments indicate that the interaction between the Rtf1 Spt5-interacting domain and the Spt5 CTR is direct. Collectively, our results provide molecular insight into a key attachment point between Paf1C and the RNA polymerase II elongation machinery.
Collapse
|
36
|
CTR9, a component of PAF complex, controls elongation block at the c-Fos locus via signal-dependent regulation of chromatin-bound NELF dissociation. PLoS One 2013; 8:e61055. [PMID: 23593388 PMCID: PMC3623864 DOI: 10.1371/journal.pone.0061055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/05/2013] [Indexed: 11/19/2022] Open
Abstract
PAF complex (PAFc) is an RNA polymerase II associated factor that controls diverse steps of transcription. Although it is generally associated with actively transcribed genes, a repressive PAFc has also been suggested. Here, we report that PAFc regulates the transition from transcription initiation to transcription elongation. PAFc repressed IL-6-induced, but not TNF-α-induced, immediate early gene expression. PAFc constitutively associated with the 5'-coding region of the c-Fos locus, then transiently dissociated upon IL-6 stimulation. When CTR9, a component of PAFc, was depleted, higher levels of serine 5-phosphorylated or serine 2-phosphorylated forms of RNA Polymerase II were associated with the unstimulated c-Fos locus. We also observed an increased association of CDK9, a kinase component of the pTEF-b elongation factor, with the c-Fos locus in the CTR9-depleted condition. Furthermore, association of negative elongation factor, NELF, which is required to proceed to the elongation phase, was significantly reduced by CTR9 depletion, whereas elongation factor SPT5 recruitment was enhanced by CTR9 depletion. Finally, the chromatin association of CTR9 was specifically controlled by IL-6-induced kinase activity, because a JAK2 kinase inhibitor, AG-490, blocked its association. In conclusion, our data suggest that PAFc controls the recruitment of NELF and SPT5 to target loci in a signal- and locus-specific manner.
Collapse
|
37
|
Marsh DJ, Hahn MA, Howell VM, Gill AJ. Molecular diagnosis of primary hyperparathyroidism in familial cancer syndromes. ACTA ACUST UNITED AC 2013; 1:377-92. [PMID: 23489357 DOI: 10.1517/17530059.1.3.377] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In the last few years, causative genes have been identified for most of the familial hyperparathyroidism conditions. Germline mutations in the tumour suppressors multiple endocrine neoplasia type 1 (MEN1) and hyperparathyroidism 2 (HRPT2) provide a molecular diagnosis of multiple endocrine neoplasia type 1 and hyperparathyroidism jaw tumour syndrome, respectively. Germline mutations in the proto-oncogene RET (rearranged during transfection) provide a molecular diagnosis of multiple endocrine neoplasia type 2. Germline mutations of both MEN1 and, less frequently HRPT2, have been found in familial isolated hyperparathyroidism. A molecular diagnosis can now be incorporated into the management of patients with these conditions, however, the ease of diagnostics and value of genetic information in the context of clinical screening and early surgical intervention varies between these disorders. This review focuses on familial hyperparathyroidism and its known causative genes in the setting of neoplastic syndromes, with particular discussion of recent developments in the molecular diagnosis of parathyroid carcinoma.
Collapse
Affiliation(s)
- Deborah J Marsh
- University of Sydney, Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia +61 2 9926 8486 ; +61 2 9926 8484 ;
| | | | | | | |
Collapse
|
38
|
Kim N, Sun HY, Youn MY, Yoo JY. IL-1β-specific recruitment of GCN5 histone acetyltransferase induces the release of PAF1 from chromatin for the de-repression of inflammatory response genes. Nucleic Acids Res 2013; 41:4495-506. [PMID: 23502002 PMCID: PMC3632138 DOI: 10.1093/nar/gkt156] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
To determine the functional specificity of inflammation, it is critical to orchestrate the timely activation and repression of inflammatory responses. Here, we explored the PAF1 (RNA polymerase II associated factor)-mediated signal- and locus-specific repression of genes induced through the pro-inflammatory cytokine interleukin (IL)-1β. Using microarray analysis, we identified the PAF1 target genes whose expression was further enhanced by PAF1 knockdown in IL-1β–stimulated HepG2 hepatocarcinomas. PAF1 bound near the transcription start sites of target genes and dissociated on stimulation. In PAF1-deficient cells, more elongating RNA polymerase II and acetylated histones were observed, although IL-1β–mediated activation and recruitment of nuclear factor κB (NF-κB) were not altered. Under basal conditions, PAF1 blocked histone acetyltransferase general control non-depressible 5 (GCN5)-mediated acetylation on H3K9 and H4K5 residues. On IL-1β stimulation, activated GCN5 discharged PAF1 from chromatin, allowing productive transcription to occur. PAF1 bound to histones but not to acetylated histones, and the chromatin-binding domain of PAF1 was essential for target gene repression. Moreover, IL-1β–induced cell migration was similarly controlled through counteraction between PAF1 and GCN5. These results suggest that the IL-1β signal-specific exchange of PAF1 and GCN5 on the target locus limits inappropriate gene induction and facilitates the timely activation of inflammatory responses.
Collapse
Affiliation(s)
- Nari Kim
- Division of Molecular and Life Sciences, Department of Life Sciences, Pohang University of Science and Technology POSTECH, Pohang 790-784, Republic of Korea
| | | | | | | |
Collapse
|
39
|
Effects of the Paf1 complex and histone modifications on snoRNA 3'-end formation reveal broad and locus-specific regulation. Mol Cell Biol 2012; 33:170-82. [PMID: 23109428 DOI: 10.1128/mcb.01233-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Across diverse eukaryotes, the Paf1 complex (Paf1C) plays critical roles in RNA polymerase II transcription elongation and regulation of histone modifications. Beyond these roles, the human and Saccharomyces cerevisiae Paf1 complexes also interact with RNA 3'-end processing components to affect transcript 3'-end formation. Specifically, the Saccharomyces cerevisiae Paf1C functions with the RNA binding proteins Nrd1 and Nab3 to regulate the termination of at least two small nucleolar RNAs (snoRNAs). To determine how Paf1C-dependent functions regulate snoRNA formation, we used high-density tiling arrays to analyze transcripts in paf1Δ cells and uncover new snoRNA targets of Paf1. Detailed examination of Paf1-regulated snoRNA genes revealed locus-specific requirements for Paf1-dependent posttranslational histone modifications. We also discovered roles for the transcriptional regulators Bur1-Bur2, Rad6, and Set2 in snoRNA 3'-end formation. Surprisingly, at some snoRNAs, this function of Rad6 appears to be primarily independent of its role in histone H2B monoubiquitylation. Cumulatively, our work reveals a broad requirement for the Paf1C in snoRNA 3'-end formation in S. cerevisiae, implicates the participation of transcriptional proteins and histone modifications in this process, and suggests that the Paf1C contributes to the fine tuning of nuanced levels of regulation that exist at individual loci.
Collapse
|
40
|
The many roles of the conserved eukaryotic Paf1 complex in regulating transcription, histone modifications, and disease states. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:116-26. [PMID: 22982193 DOI: 10.1016/j.bbagrm.2012.08.011] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/18/2012] [Accepted: 08/29/2012] [Indexed: 12/20/2022]
Abstract
The Paf1 complex was originally identified over fifteen years ago in budding yeast through its physical association with RNA polymerase II. The Paf1 complex is now known to be conserved throughout eukaryotes and is well studied for promoting RNA polymerase II transcription elongation and transcription-coupled histone modifications. Through these critical regulatory functions, the Paf1 complex participates in numerous cellular processes such as gene expression and silencing, RNA maturation, DNA repair, cell cycle progression and prevention of disease states in higher eukaryotes. In this review, we describe the historic and current research involving the eukaryotic Paf1 complex to explain the cellular roles that underlie its conservation and functional importance. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
Collapse
|
41
|
Chen H, Shi N, Gao Y, Li X, Teng M, Niu L. Crystallographic analysis of the conserved C-terminal domain of transcription factor Cdc73 from Saccharomyces cerevisiae reveals a GTPase-like fold. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:953-9. [PMID: 22868760 DOI: 10.1107/s0907444912017325] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 04/18/2012] [Indexed: 11/10/2022]
Abstract
The yeast Paf1 complex (Paf1C), which is composed of the proteins Paf1, Cdc73, Ctr9, Leo1 and Rtf1, accompanies RNA polymerase II from the promoter to the 3'-end formation site of mRNA- and snoRNA-encoding genes. As one of the first identified subunits of Paf1C, yeast Cdc73 (yCdc73) takes part in many transcription-related processes, including binding to RNA polymerase II, recruitment and activation of histone-modification factors and communication with other transcriptional activators. The human homologue of yCdc73, parafibromin, has been identified as a tumour suppressor linked to breast, renal and gastric cancers. However, the functional mechanism of yCdc73 has until recently been unclear. Here, a 2.2 Å resolution crystal structure of the highly conserved C-terminal region of yCdc73 is reported. It revealed that yCdc73 appears to have a GTPase-like fold. However, no GTPase activity was observed. The crystal structure of yCdc73 will shed new light on the modes of function of Cdc73 and Paf1C.
Collapse
Affiliation(s)
- Hongkai Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | | | | | | | | | | |
Collapse
|
42
|
Zhang JH, Seigneur EM, Pandey M, Loshakov A, Dagur PK, Connelly PS, Koo L, Panicker LM, Simonds WF. The EIF4EBP3 translational repressor is a marker of CDC73 tumor suppressor haploinsufficiency in a parathyroid cancer syndrome. Cell Death Dis 2012; 3:266. [PMID: 22297294 PMCID: PMC3288348 DOI: 10.1038/cddis.2012.6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Germline mutation of the tumor suppressor gene CDC73 confers susceptibility to the hyperparathyroidism-jaw tumor syndrome associated with a high risk of parathyroid malignancy. Inactivating CDC73 mutations have also been implicated in sporadic parathyroid cancer, but are rare in sporadic benign parathyroid tumors. The molecular pathways that distinguish malignant from benign parathyroid transformation remain elusive. We previously showed that a hypomorphic allele of hyrax (hyx), the Drosophila homolog of CDC73, rescues the loss-of-ventral-eye phenotype of lobe, encoding the fly homolog of Akt1s1/ PRAS40. We report now an interaction between hyx and Tor, a central regulator of cell growth and autophagy, and show that eukaryotic translation initiation factor 4E-binding protein (EIF4EBP), a translational repressor and effector of mammalian target of rapamycin (mTOR), is a conserved target of hyx/CDC73. Flies heterozygous for Tor and hyx, but not Mnn1, the homolog of the multiple endocrine neoplasia type 1 (MEN1) tumor suppressor associated with benign parathyroid tumors, are starvation resistant with reduced basal levels of Thor/4E-BP. Human peripheral blood cell levels of EIF4EBP3 were reduced in patients with CDC73, but not MEN1, heterozygosity. Chromatin immunoprecipitation demonstrated occupancy of EIF4EBP3 by endogenous parafibromin. These results show that EIF4EBP3 is a peripheral marker of CDC73 function distinct from MEN1-regulated pathways, and suggest a model whereby starvation resistance and/or translational de-repression contributes to parathyroid malignant transformation.
Collapse
Affiliation(s)
- J-H Zhang
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Paf1 restricts Gcn4 occupancy and antisense transcription at the ARG1 promoter. Mol Cell Biol 2012; 32:1150-63. [PMID: 22252319 DOI: 10.1128/mcb.06262-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conserved Paf1 complex negatively regulates the expression of numerous genes, yet the mechanisms by which it represses gene expression are not well understood. In this study, we use the ARG1 gene as a model to investigate the repressive functions of the Paf1 complex in Saccharomyces cerevisiae. Our results indicate that Paf1 mediates repression of the ARG1 gene independently of the gene-specific repressor, ArgR/Mcm1. Rather, by promoting histone H2B lysine 123 ubiquitylation, Paf1 represses the ARG1 gene by negatively affecting Gcn4 occupancy at the promoter. Consistent with this observation, Gcn5 and its acetylation sites on histone H3 are required for full ARG1 derepression in paf1Δ cells, and the repressive effect of Paf1 is largely maintained when the ARG1 promoter directs transcription of a heterologous coding region. Derepression of the ARG1 gene in paf1Δ cells is accompanied by small changes in nucleosome occupancy, although these changes are subtle in comparison to those that accompany gene activation through amino acid starvation. Additionally, conditions that stimulate ARG1 transcription, including PAF1 deletion, lead to increased antisense transcription across the ARG1 promoter. This promoter-associated antisense transcription positively correlates with ARG1 sense transcription. Finally, our results indicate that Paf1 represses other genes through mechanisms similar to those used at the ARG1 gene.
Collapse
|
44
|
Crisucci EM, Arndt KM. The Roles of the Paf1 Complex and Associated Histone Modifications in Regulating Gene Expression. GENETICS RESEARCH INTERNATIONAL 2011; 2011. [PMID: 22408743 PMCID: PMC3296560 DOI: 10.4061/2011/707641] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The conserved Paf1 complex (Paf1C) carries out multiple functions during transcription by RNA polymerase (pol) II, and these functions are required for the proper expression of numerous genes in yeast and metazoans. In the elongation stage of the transcription cycle, the Paf1C associates with RNA pol II, interacts with other transcription elongation factors, and facilitates modifications to the chromatin template. At the end of elongation, the Paf1C plays an important role in the termination of RNA pol II transcripts and the recruitment of proteins required for proper RNA 3′ end formation. Significantly, defects in the Paf1C are associated with several human diseases. In this paper, we summarize current knowledge on the roles of the Paf1C in RNA pol II transcription.
Collapse
Affiliation(s)
- Elia M Crisucci
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | |
Collapse
|
45
|
Lawson ND, Wolfe SA. Forward and reverse genetic approaches for the analysis of vertebrate development in the zebrafish. Dev Cell 2011; 21:48-64. [PMID: 21763608 DOI: 10.1016/j.devcel.2011.06.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The development of facile forward and reverse genetic approaches has propelled the deconvolution of gene function in biology. While the origins of these techniques reside in the study of single-cell or invertebrate organisms, in many cases these approaches have been applied to vertebrate model systems to gain powerful insights into gene function during embryonic development. This perspective provides a summary of the major forward and reverse genetic approaches that have contributed to the study of vertebrate gene function in zebrafish, which has become an established model for the study of animal development.
Collapse
Affiliation(s)
- Nathan D Lawson
- Program in Gene Function and Expression, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | | |
Collapse
|
46
|
The Paf1 complex represses SER3 transcription in Saccharomyces cerevisiae by facilitating intergenic transcription-dependent nucleosome occupancy of the SER3 promoter. EUKARYOTIC CELL 2011; 10:1283-94. [PMID: 21873510 DOI: 10.1128/ec.05141-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Previous studies have shown that repression of the Saccharomyces cerevisiae SER3 gene is dependent on transcription of SRG1 from noncoding DNA initiating within the intergenic region 5' of SER3 and extending across the SER3 promoter region. By a mechanism dependent on the activities of the Swi/Snf chromatin remodeling factor, the HMG-like factor Spt2, and the Spt6 and Spt16 histone chaperones, SRG1 transcription deposits nucleosomes over the SER3 promoter to prevent transcription factors from binding and activating SER3. In this study, we uncover a role for the Paf1 transcription elongation complex in SER3 repression. We find that SER3 repression is primarily dependent on the Paf1 and Ctr9 subunits of this complex, with minor contributions by the Rtf1, Cdc73, and Leo1 subunits. We show that the Paf1 complex localizes to the SRG1 transcribed region under conditions that repress SER3, consistent with it having a direct role in mediating SRG1 transcription-dependent SER3 repression. Importantly, we show that the defect in SER3 repression in strains lacking Paf1 subunits is not a result of reduced SRG1 transcription or reduced levels of known Paf1 complex-dependent histone modifications. Rather, we find that strains lacking subunits of the Paf1 complex exhibit reduced nucleosome occupancy and reduced recruitment of Spt16 and, to a lesser extent, Spt6 at the SER3 promoter. Taken together, our results suggest that Paf1 and Ctr9 repress SER3 by maintaining SRG1 transcription-dependent nucleosome occupancy.
Collapse
|
47
|
The Paf1 complex represses ARG1 transcription in Saccharomyces cerevisiae by promoting histone modifications. EUKARYOTIC CELL 2011; 10:712-23. [PMID: 21498644 DOI: 10.1128/ec.05013-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The conserved multifunctional Paf1 complex is important for the proper transcription of numerous genes, and yet the exact mechanisms by which it controls gene expression remain unclear. While previous studies indicate that the Paf1 complex is a positive regulator of transcription, the repression of many genes also requires the Paf1 complex. In this study we used ARG1 as a model gene to study transcriptional repression by the Paf1 complex in Saccharomyces cerevisiae. We found that several members of the Paf1 complex contribute to ARG1 repression and that the complex localizes to the ARG1 promoter and coding region in repressing conditions, which is consistent with a direct repressive function. Furthermore, Paf1 complex-dependent histone modifications are enriched at the ARG1 locus in repressing conditions, and histone H3 lysine 4 methylation contributes to ARG1 repression. Consistent with previous reports, histone H2B monoubiquitylation, the mark upstream of histone H3 lysine 4 methylation, is also important for ARG1 repression. To begin to identify the mechanistic basis for Paf1 complex-mediated repression of ARG1, we focused on the Rtf1 subunit of the complex. Through an analysis of RTF1 mutations that abrogate known Rtf1 activities, we found that Rtf1 mediates ARG1 repression primarily by facilitating histone modifications. Other members of the Paf1 complex, such as Paf1, appear to repress ARG1 through additional mechanisms. Together, our results suggest that Rtf1-dependent histone H2B ubiquitylation and H3 K4 methylation repress ARG1 expression and that histone modifications normally associated with active transcription can occur at repressed loci and contribute to transcriptional repression.
Collapse
|
48
|
Identification of a role for histone H2B ubiquitylation in noncoding RNA 3'-end formation through mutational analysis of Rtf1 in Saccharomyces cerevisiae. Genetics 2011; 188:273-89. [PMID: 21441211 DOI: 10.1534/genetics.111.128645] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conserved eukaryotic Paf1 complex regulates RNA synthesis by RNA polymerase II at multiple levels, including transcript elongation, transcript termination, and chromatin modifications. To better understand the contributions of the Paf1 complex to transcriptional regulation, we generated mutations that alter conserved residues within the Rtf1 subunit of the Saccharomyces cerevisiae Paf1 complex. Importantly, single amino acid substitutions within a region of Rtf1 that is conserved from yeast to humans, which we termed the histone modification domain, resulted in the loss of histone H2B ubiquitylation and impaired histone H3 methylation. Phenotypic analysis of these mutations revealed additional defects in telomeric silencing, transcription elongation, and prevention of cryptic initiation. We also demonstrated that amino acid substitutions within the Rtf1 histone modification domain disrupt 3'-end formation of snoRNA transcripts and identify a previously uncharacterized regulatory role for the histone H2B K123 ubiquitylation mark in this process. Cumulatively, our results reveal functionally important residues in Rtf1, better define the roles of Rtf1 in transcription and histone modification, and provide strong genetic support for the participation of histone modification marks in the termination of noncoding RNAs.
Collapse
|
49
|
Langenbacher AD, Nguyen CT, Cavanaugh AM, Huang J, Lu F, Chen JN. The PAF1 complex differentially regulates cardiomyocyte specification. Dev Biol 2011; 353:19-28. [PMID: 21338598 DOI: 10.1016/j.ydbio.2011.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/07/2011] [Accepted: 02/11/2011] [Indexed: 11/28/2022]
Abstract
The specification of an appropriate number of cardiomyocytes from the lateral plate mesoderm requires a careful balance of both positive and negative regulatory signals. To identify new regulators of cardiac specification, we performed a phenotype-driven ENU mutagenesis forward genetic screen in zebrafish. In our genetic screen we identified a zebrafish ctr9 mutant with a dramatic reduction in myocardial cell number as well as later defects in primitive heart tube elongation and atrioventricular boundary patterning. Ctr9, together with Paf1, Cdc73, Rtf1 and Leo1, constitute the RNA polymerase II associated protein complex, PAF1. We demonstrate that the PAF1 complex (PAF1C) is structurally conserved among zebrafish and other metazoans and that loss of any one of the components of the PAF1C results in abnormal development of the atrioventricular boundary of the heart. However, Ctr9, Cdc73, Paf1 and Rtf1, but not Leo1, are required for the specification of an appropriate number of cardiomyocytes and elongation of the heart tube. Interestingly, loss of Rtf1 function produced the most severe defects, resulting in a nearly complete absence of cardiac precursors. Based on gene expression analyses and transplantation studies, we found that the PAF1C regulates the developmental potential of the lateral plate mesoderm and is required cell autonomously for the specification of cardiac precursors. Our findings demonstrate critical but differential requirements for PAF1C components in zebrafish cardiac specification and heart morphogenesis.
Collapse
Affiliation(s)
- Adam D Langenbacher
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | | | | | | | | | | |
Collapse
|
50
|
Abstract
Parathyroid cancer is an uncommon malignancy and rare cause of primary hyperparathyroidism (HPT) with a high morbidity and patient death in advanced cases usually resulting from intractable hypercalcemia. Inactivation of the HRPT2/CDC73 gene, encoding the putative tumor-suppressor protein parafibromin and discovered in the context of the hyperparathyroidism-jaw tumor (HPT-JT) syndrome, is a common, somatic event in most parathyroid cancers. Approximately 25% of patients with apparently sporadic parathyroid cancer carry germline HRPT2/CDC73 mutation. Germline DNA analysis for HRPT2/CDC73 mutation is recommended in all patients with parathyroid cancer because of the potential benefit for first-degree relatives, who should nevertheless undergo serum calcium screening. The histopathologic diagnosis of parathyroid cancer is nonspecific unless vascular, lymphatic, capsular, or soft tissue invasion is seen, or metastases are clinically evident. Immunohistochemical analysis of parathyroid tumors for loss of parafibromin expression offers promise as a diagnostic tool. En bloc tumor resection offers the highest chance of cure in patients with suspected parathyroid carcinoma. No adjuvant chemotherapy regimen has yet proven effective, and the role of local adjuvant radiotherapy is being evaluated. Metastatic disease can be palliated with surgical debulking. Medical therapy with the calcimimetic cinacalcet and bisphosphonates can ameliorate hypercalcemia in patients with inoperable disease.
Collapse
Affiliation(s)
- John M Sharretts
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892–1752, USA
| | | | | |
Collapse
|