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Nazarov IB, Zilov DS, Gordeev MN, Potapenko EV, Yeremenko N, Tomilin AN. Transcriptional Coactivator BOB1 (OBF1, OCA-B) Modulates the Specificity of DNA Recognition by the POU-Domain Factors OCT1 and OCT2 in a Monomeric Configuration. Biomolecules 2024; 14:123. [PMID: 38254723 PMCID: PMC10812921 DOI: 10.3390/biom14010123] [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: 11/13/2023] [Revised: 01/05/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
BOB1, a mammalian lymphocyte-specific transcriptional coactivator of the transcription factors OCT1 and OCT2 (OCT1/2), plays important roles in normal immune responses, autoimmunity, and hematologic malignancies. The issue of a DNA sequence preference change imposed by BOB1 was raised more than two decades ago but remains unresolved. In this paper, using the EMSA-SELEX-Seq approach, we have reassessed the intrinsic ability of BOB1 to modulate the specificity of DNA recognition by OCT1 and OCT2. Our results have reaffirmed previous conclusions regarding BOB1 selectivity towards the dimer configuration of OCT1/2. However, they suggest that the monomeric configuration of these factors, assembled on the classical octamer ATGCAAAT and related motifs, are the primary targets of BOB1. Our data further specify the DNA sequence preference imposed by BOB1 and predict the probability of ternary complex formation. These results provide an additional insight into the action of BOB1-an essential immune regulator and a promising molecular target for the treatment of autoimmune diseases and hematologic malignancies.
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Affiliation(s)
- Igor B. Nazarov
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia; (D.S.Z.); (M.N.G.)
| | - Danil S. Zilov
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia; (D.S.Z.); (M.N.G.)
| | - Mikhail N. Gordeev
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia; (D.S.Z.); (M.N.G.)
| | - Evgenii V. Potapenko
- Institute of Evolution, University of Haifa, Haifa 3498838, Israel;
- University of Haifa, Haifa 3498838, Israel
| | - Nataliya Yeremenko
- Center for Research in Transplantation and Translational Immunology UMR1064, 30 Bd Jean Monnet, Nantes University, CEDEX 01, 44093 Nantes, France;
| | - Alexey N. Tomilin
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia; (D.S.Z.); (M.N.G.)
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2
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Han D, Wu G, Chen R, Drexler HCA, MacCarthy CM, Kim KP, Adachi K, Gerovska D, Mavrommatis L, Bedzhov I, Araúzo-Bravo MJ, Schöler HR. A balanced Oct4 interactome is crucial for maintaining pluripotency. SCIENCE ADVANCES 2022; 8:eabe4375. [PMID: 35171666 PMCID: PMC8849292 DOI: 10.1126/sciadv.abe4375] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Oct4 collaborates primarily with other transcriptional factors or coregulators to maintain pluripotency. However, how Oct4 exerts its function is still unclear. Here, we show that the Oct4 linker interface mediates competing yet balanced Oct4 protein interactions that are crucial for maintaining pluripotency. Oct4 linker mutant embryonic stem cells (ESCs) show decreased expression of self-renewal genes and increased expression of differentiation genes, resulting in impaired ESC self-renewal and early embryonic development. The linker mutation interrupts the balanced Oct4 interactome. In mutant ESCs, the interaction between Oct4 and Klf5 is decreased. In contrast, interactions between Oct4 and Cbx1, Ctr9, and Cdc73 are increased, disrupting the epigenetic state of ESCs. Control of the expression level of Klf5, Cbx1, or Cdc73 rebalances the Oct4 interactome and rescues the pluripotency of linker mutant ESCs, indicating that such factors interact with Oct4 competitively. Thus, we provide previously unidentified molecular insights into how Oct4 maintains pluripotency.
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Affiliation(s)
- Dong Han
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Guangming Wu
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 6 Luoxuan Avenue, Haizhu District, 510320 Guangzhou, P. R. China
| | - Rui Chen
- Embryonic Self-Organization Research Group, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Hannes C. A. Drexler
- Bioanalytical Mass Spectrometry, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Caitlin M. MacCarthy
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Kee-Pyo Kim
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, 222 Banpo-daero Seocho-gu, Seoul 06591, Republic of Korea
| | - Kenjiro Adachi
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Daniela Gerovska
- Group of Computational Biology and Systems Biomedicine, Biodonostia Health Research Institute, San Sebastian 20014, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48011, Spain
| | - Lampros Mavrommatis
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Ivan Bedzhov
- Embryonic Self-Organization Research Group, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Marcos J. Araúzo-Bravo
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
- Group of Computational Biology and Systems Biomedicine, Biodonostia Health Research Institute, San Sebastian 20014, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao 48011, Spain
| | - Hans R. Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
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OBF1 and Oct factors control the germinal center transcriptional program. Blood 2021; 137:2920-2934. [PMID: 33512466 DOI: 10.1182/blood.2020010175] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
OBF1 is a specific coactivator of the POU family transcription factors OCT1 and OCT2. OBF1 and OCT2 are B cell-specific and indispensable for germinal center (GC) formation, but their mechanism of action is unclear. Here, we show by chromatin immunoprecipitation-sequencing that OBF1 extensively colocalizes with OCT1 and OCT2. We found that these factors also often colocalize with transcription factors of the ETS family. Furthermore, we showed that OBF1, OCT2, and OCT1 bind widely to the promoters or enhancers of genes involved in GC formation in mouse and human GC B cells. Short hairpin RNA knockdown experiments demonstrated that OCT1, OCT2, and OBF1 regulate each other and are essential for proliferation of GC-derived lymphoma cell lines. OBF1 downregulation disrupts the GC transcriptional program: genes involved in GC maintenance, such as BCL6, are downregulated, whereas genes related to exit from the GC program, such as IRF4, are upregulated. Ectopic expression of BCL6 does not restore the proliferation of GC-derived lymphoma cells depleted of OBF1 unless IRF4 is also depleted, indicating that OBF1 controls an essential regulatory node in GC differentiation.
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4
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Wang Y, Liu S, Chen Q, Ren Y, Li Z, Cao S. Novel small molecular inhibitor of Pit-Oct-Unc transcription factor 1 suppresses hepatocellular carcinoma cell proliferation. Life Sci 2021; 277:119521. [PMID: 33891940 DOI: 10.1016/j.lfs.2021.119521] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 02/07/2023]
Abstract
Hepatocellular carcinoma (HCC) is one of the most prevalent fatal malignancies in the Chinese population, due to high rates of hepatitis virus infection. Molecular targeted drugs such as sorafenib are the anti-tumor agents of choice for HCC treatment, but their results are generally unsatisfactory. In the present study the use of Pit-Oct-Unc transcription factor 1 (OCT1/POU2F1) as a potential therapeutic target for HCC was investigated, and a novel small molecular inhibitor of OCT1 (SMIO-1) was designed and its therapeutic efficacy against HCC was assessed. OCT1 expression was higher in HCC specimens than in corresponding non-tumor tissues, and higher OCT1 was associated with poorer prognosis in advanced HCC patients undergoing sorafenib treatment. For the first time, the novel SMIO-1 was investigated in conjunction with OCT1 via molecular docking. Interaction between SMIO-1 and OCT1 was confirmed via OCT1 point mutation. Treatment with SMIO-1 repressed OCT1 transcription factor activation by disrupting the interaction between OCT1 and its cofactors. It also repressed the proliferation and metastasis of HCC cells, and inhibited proliferation-related and metastasis-related genes downstream of OCT1. Therefore, SMIO-1 is a promising strategy for HCC treatment.
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Affiliation(s)
- Yue Wang
- Department of Pharmacy, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Number 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, People's Republic of China.
| | - Shuo Liu
- Department of Pharmacy, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Number 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, People's Republic of China
| | - Qin Chen
- Department of Pharmacy, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Number 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, People's Republic of China
| | - Yixin Ren
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430072, Hubei Province, People's Republic of China
| | - Zhongxiang Li
- Department of Pharmacy, The First Hospital of China Medical University, Shenyang 110001, Liaoning Province, People's Republic of China.
| | - Shuang Cao
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430072, Hubei Province, People's Republic of China.
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Yeremenko N, Danger R, Baeten D, Tomilin A, Brouard S. Transcriptional regulator BOB.1: Molecular mechanisms and emerging role in chronic inflammation and autoimmunity. Autoimmun Rev 2021; 20:102833. [PMID: 33864944 DOI: 10.1016/j.autrev.2021.102833] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022]
Abstract
Lymphocytes constitute an essential and potent effector compartment of the immune system. Therefore, their development and functions must be strictly regulated to avoid inappropriate immune responses, such as autoimmune reactions. Several lines of evidence from genetics (e.g. association with multiple sclerosis and primary biliary cirrhosis), human expression studies (e.g. increased expression in target tissues and draining lymph nodes of patients with autoimmune diseases), animal models (e.g. loss of functional protein protects animals from the development of collagen-induced arthritis, experimental autoimmune encephalomyelitis, type 1 diabetes, bleomycin-induced fibrosis) strongly support a causal link between the aberrant expression of the lymphocyte-restricted transcriptional regulator BOB.1 and the development of autoimmune diseases. In this review, we summarize the current knowledge of unusual structural and functional plasticity of BOB.1, stringent regulation of its expression, and the pivotal role that BOB.1 plays in shaping B- and T-cell responses. We discuss recent developments highlighting the significant contribution of BOB.1 to the pathogenesis of autoimmune diseases and how to leverage our knowledge to target this regulator to treat autoimmune tissue inflammation.
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Affiliation(s)
- Nataliya Yeremenko
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France; Amsterdam Rheumatology and Immunology Center, Department of Clinical Immunology and Rheumatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands; Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.
| | - Richard Danger
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Dominique Baeten
- Amsterdam Rheumatology and Immunology Center, Department of Clinical Immunology and Rheumatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands; Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Alexey Tomilin
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russian Federation
| | - Sophie Brouard
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
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6
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Hitomi Y, Aiba Y, Kawai Y, Kojima K, Ueno K, Nishida N, Kawashima M, Gervais O, Khor SS, Nagasaki M, Tokunaga K, Nakamura M, Tsuiji M. rs1944919 on chromosome 11q23.1 and its effector genes COLCA1/COLCA2 confer susceptibility to primary biliary cholangitis. Sci Rep 2021; 11:4557. [PMID: 33633225 PMCID: PMC7907150 DOI: 10.1038/s41598-021-84042-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/11/2021] [Indexed: 01/12/2023] Open
Abstract
Primary biliary cholangitis (PBC) is a chronic, progressive cholestatic liver disease in which intrahepatic bile ducts are destroyed by an autoimmune reaction. Our previous genome-wide association study (GWAS) identified chromosome 11q23.1 as a susceptibility gene locus for PBC in the Japanese population. Here, high-density association mapping based on single nucleotide polymorphism (SNP) imputation and in silico/in vitro functional analyses identified rs1944919 as the primary functional variant. Expression-quantitative trait loci analyses showed that the PBC susceptibility allele of rs1944919 was significantly associated with increased COLCA1/COLCA2 expression levels. Additionally, the effects of rs1944919 on COLCA1/COLCA2 expression levels were confirmed using genotype knock-in versions of cell lines constructed using the CRISPR/Cas9 system and differed between rs1944919-G/G clones and -T/T clones. To our knowledge, this is the first study to demonstrate the contribution of COLCA1/COLCA2 to PBC susceptibility.
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Affiliation(s)
- Yuki Hitomi
- Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
| | - Yoshihiro Aiba
- Clinical Research Center, National Hospital Organization (NHO) Nagasaki Medical Center, Omura, Japan
| | - Yosuke Kawai
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kaname Kojima
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Kazuko Ueno
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo, Japan
| | - Nao Nishida
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo, Japan.,The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Japan
| | | | - Olivier Gervais
- Human Biosciences Unit for the Top Global Course Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
| | - Seik-Soon Khor
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masao Nagasaki
- Human Biosciences Unit for the Top Global Course Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan
| | - Katsushi Tokunaga
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo, Japan
| | - Minoru Nakamura
- Clinical Research Center, National Hospital Organization (NHO) Nagasaki Medical Center, Omura, Japan.,Department of Hepatology, Nagasaki University Graduate School of Biomedical Sciences, Omura, Japan.,Headquarters of PBC Research in NHO Study Group for Liver Disease in Japan (NHOSLJ), Clinical Research Center, NHO Nagasaki Medical Center, Omura, Japan
| | - Makoto Tsuiji
- Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
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7
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Malik V, Zimmer D, Jauch R. Diversity among POU transcription factors in chromatin recognition and cell fate reprogramming. Cell Mol Life Sci 2018; 75:1587-1612. [PMID: 29335749 PMCID: PMC11105716 DOI: 10.1007/s00018-018-2748-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/23/2017] [Accepted: 01/08/2018] [Indexed: 12/28/2022]
Abstract
The POU (Pit-Oct-Unc) protein family is an evolutionary ancient group of transcription factors (TFs) that bind specific DNA sequences to direct gene expression programs. The fundamental importance of POU TFs to orchestrate embryonic development and to direct cellular fate decisions is well established, but the molecular basis for this activity is insufficiently understood. POU TFs possess a bipartite 'two-in-one' DNA binding domain consisting of two independently folding structural units connected by a poorly conserved and flexible linker. Therefore, they represent a paradigmatic example to study the molecular basis for the functional versatility of TFs. Their modular architecture endows POU TFs with the capacity to accommodate alternative composite DNA sequences by adopting different quaternary structures. Moreover, associations with partner proteins crucially influence the selection of their DNA binding sites. The plentitude of DNA binding modes confers the ability to POU TFs to regulate distinct genes in the context of different cellular environments. Likewise, different binding modes of POU proteins to DNA could trigger alternative regulatory responses in the context of different genomic locations of the same cell. Prominent POU TFs such as Oct4, Brn2, Oct6 and Brn4 are not only essential regulators of development but have also been successfully employed to reprogram somatic cells to pluripotency and neural lineages. Here we review biochemical, structural, genomic and cellular reprogramming studies to examine how the ability of POU TFs to select regulatory DNA, alone or with partner factors, is tied to their capacity to epigenetically remodel chromatin and drive specific regulatory programs that give cells their identities.
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Affiliation(s)
- Vikas Malik
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Dennis Zimmer
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Ralf Jauch
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 511436, China.
- Genome Regulation Laboratory, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
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8
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Zhou H, Brekman A, Zuo WL, Ou X, Shaykhiev R, Agosto-Perez FJ, Wang R, Walters MS, Salit J, Strulovici-Barel Y, Staudt MR, Kaner RJ, Mezey JG, Crystal RG, Wang G. POU2AF1 Functions in the Human Airway Epithelium To Regulate Expression of Host Defense Genes. THE JOURNAL OF IMMUNOLOGY 2016; 196:3159-67. [PMID: 26927796 DOI: 10.4049/jimmunol.1502400] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/01/2016] [Indexed: 02/05/2023]
Abstract
In the process of seeking novel lung host defense regulators by analyzing genome-wide RNA sequence data from normal human airway epithelium, we detected expression of POU domain class 2-associating factor 1 (POU2AF1), a known transcription cofactor previously thought to be expressed only in lymphocytes. Lymphocyte contamination of human airway epithelial samples obtained by bronchoscopy and brushing was excluded by immunohistochemistry staining, the observation of upregulation of POU2AF1 in purified airway basal stem/progenitor cells undergoing differentiation, and analysis of differentiating single basal cell clones. Lentivirus-mediated upregulation of POU2AF1 in airway basal cells induced upregulation of host defense genes, including MX1, IFIT3, IFITM, and known POU2AF1 downstream genes HLA-DRA, ID2, ID3, IL6, and BCL6. Interestingly, expression of these genes paralleled changes of POU2AF1 expression during airway epithelium differentiation in vitro, suggesting POU2AF1 helps to maintain a host defense tone even in pathogen-free condition. Cigarette smoke, a known risk factor for airway infection, suppressed POU2AF1 expression both in vivo in humans and in vitro in human airway epithelial cultures, accompanied by deregulation of POU2AF1 downstream genes. Finally, enhancing POU2AF1 expression in human airway epithelium attenuated the suppression of host defense genes by smoking. Together, these findings suggest a novel function of POU2AF1 as a potential regulator of host defense genes in the human airway epithelium.
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Affiliation(s)
- Haixia Zhou
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Sichuan 610041, China; Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Angelika Brekman
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Wu-Lin Zuo
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Xuemei Ou
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Renat Shaykhiev
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | | | - Rui Wang
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Matthew S Walters
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Jacqueline Salit
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | | | - Michelle R Staudt
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Robert J Kaner
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, NY 10065; and
| | - Jason G Mezey
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, NY 14853
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, NY 10065; and
| | - Guoqing Wang
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
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9
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Morris SA, Cahan P, Li H, Zhao AM, San Roman AK, Shivdasani RA, Collins JJ, Daley GQ. Dissecting engineered cell types and enhancing cell fate conversion via CellNet. Cell 2014; 158:889-902. [PMID: 25126792 DOI: 10.1016/j.cell.2014.07.021] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/28/2014] [Accepted: 07/17/2014] [Indexed: 12/16/2022]
Abstract
Engineering clinically relevant cells in vitro holds promise for regenerative medicine, but most protocols fail to faithfully recapitulate target cell properties. To address this, we developed CellNet, a network biology platform that determines whether engineered cells are equivalent to their target tissues, diagnoses aberrant gene regulatory networks, and prioritizes candidate transcriptional regulators to enhance engineered conversions. Using CellNet, we improved B cell to macrophage conversion, transcriptionally and functionally, by knocking down predicted B cell regulators. Analyzing conversion of fibroblasts to induced hepatocytes (iHeps), CellNet revealed an unexpected intestinal program regulated by the master regulator Cdx2. We observed long-term functional engraftment of mouse colon by iHeps, thereby establishing their broader potential as endoderm progenitors and demonstrating direct conversion of fibroblasts into intestinal epithelium. Our studies illustrate how CellNet can be employed to improve direct conversion and to uncover unappreciated properties of engineered cells.
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Affiliation(s)
- Samantha A Morris
- Stem Cell Transplantation Program, Division of Pediatric Hematology and Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital and Dana Farber Cancer Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Patrick Cahan
- Stem Cell Transplantation Program, Division of Pediatric Hematology and Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital and Dana Farber Cancer Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Hu Li
- Center for Individualized Medicine, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Anna M Zhao
- Stem Cell Transplantation Program, Division of Pediatric Hematology and Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital and Dana Farber Cancer Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Adrianna K San Roman
- Department of Medical Oncology Dana-Farber Cancer Institute, Boston, MA 02215, USA; Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Ramesh A Shivdasani
- Department of Medical Oncology Dana-Farber Cancer Institute, Boston, MA 02215, USA; Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - James J Collins
- Howard Hughes Medical Institute, Department of Biomedical Engineering and Center for BioDynamics, Boston University; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02215, USA
| | - George Q Daley
- Stem Cell Transplantation Program, Division of Pediatric Hematology and Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital and Dana Farber Cancer Institute, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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10
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Corcoran L, Emslie D, Kratina T, Shi W, Hirsch S, Taubenheim N, Chevrier S. Oct2 and Obf1 as Facilitators of B:T Cell Collaboration during a Humoral Immune Response. Front Immunol 2014; 5:108. [PMID: 24688485 PMCID: PMC3960507 DOI: 10.3389/fimmu.2014.00108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/03/2014] [Indexed: 11/16/2022] Open
Abstract
The Oct2 protein, encoded by the Pou2f2 gene, was originally predicted to act as a DNA binding transcriptional activator of immunoglobulin (Ig) in B lineage cells. This prediction flowed from the earlier observation that an 8-bp sequence, the “octamer motif,” was a highly conserved component of most Ig gene promoters and enhancers, and evidence from over-expression and reporter assays confirmed Oct2-mediated, octamer-dependent gene expression. Complexity was added to the story when Oct1, an independently encoded protein, ubiquitously expressed from the Pou2f1 gene, was characterized and found to bind to the octamer motif with almost identical specificity, and later, when the co-activator Obf1 (OCA-B, Bob.1), encoded by the Pou2af1 gene, was cloned. Obf1 joins Oct2 (and Oct1) on the DNA of a subset of octamer motifs to enhance their transactivation strength. While these proteins variously carried the mantle of determinants of Ig gene expression in B cells for many years, such a role has not been borne out for them by characterization of mice lacking functional copies of the genes, either as single or as compound mutants. Instead, we and others have shown that Oct2 and Obf1 are required for B cells to mature fully in vivo, for B cells to respond to the T cell cytokines IL5 and IL4, and for B cells to produce IL6 normally during a T cell dependent immune response. We show here that Oct2 affects Syk gene expression, thus influencing B cell receptor signaling, and that Oct2 loss blocks Slamf1 expression in vivo as a result of incomplete B cell maturation. Upon IL4 signaling, Stat6 up-regulates Obf1, indirectly via Xbp1, to enable plasma cell differentiation. Thus, Oct2 and Obf1 enable B cells to respond normally to antigen receptor signals, to express surface receptors that mediate physical interaction with T cells, or to produce and respond to cytokines that are critical drivers of B cell and T cell differentiation during a humoral immune response.
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Affiliation(s)
- Lynn Corcoran
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Dianne Emslie
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Tobias Kratina
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Wei Shi
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Susanne Hirsch
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Nadine Taubenheim
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Stephane Chevrier
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
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11
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Mueller K, Quandt J, Marienfeld RB, Weihrich P, Fiedler K, Claussnitzer M, Laumen H, Vaeth M, Berberich-Siebelt F, Serfling E, Wirth T, Brunner C. Octamer-dependent transcription in T cells is mediated by NFAT and NF-κB. Nucleic Acids Res 2013; 41:2138-54. [PMID: 23293002 PMCID: PMC3575799 DOI: 10.1093/nar/gks1349] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The transcriptional co-activator BOB.1/OBF.1 was originally identified in B cells and is constitutively expressed throughout B cell development. BOB.1/OBF.1 associates with the transcription factors Oct1 and Oct2, thereby enhancing octamer-dependent transcription. In contrast, in T cells, BOB.1/OBF.1 expression is inducible by treatment of cells with PMA/Ionomycin or by antigen receptor engagement, indicating a marked difference in the regulation of BOB.1/OBF.1 expression in B versus T cells. The molecular mechanisms underlying the differential expression of BOB.1/OBF.1 in T and B cells remain largely unknown. Therefore, the present study focuses on mechanisms controlling the transcriptional regulation of BOB.1/OBF.1 and Oct2 in T cells. We show that both calcineurin- and NF-κB-inhibitors efficiently attenuate the expression of BOB.1/OBF.1 and Oct2 in T cells. In silico analyses of the BOB.1/OBF.1 promoter revealed the presence of previously unappreciated combined NFAT/NF-κB sites. An array of genetic and biochemical analyses illustrates the involvement of the Ca2+/calmodulin-dependent phosphatase calcineurin as well as NFAT and NF-κB transcription factors in the transcriptional regulation of octamer-dependent transcription in T cells. Conclusively, impaired expression of BOB.1/OBF.1 and Oct2 and therefore a hampered octamer-dependent transcription may participate in T cell-mediated immunodeficiency caused by the deletion of NFAT or NF-κB transcription factors.
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Affiliation(s)
- Kerstin Mueller
- Institute of Physiological Chemistry, University Ulm, D-89081 Ulm, Germany, Institute of Pathology, University Ulm, D-89081 Ulm, Germany
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12
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Karnowski A, Chevrier S, Belz GT, Mount A, Emslie D, D'Costa K, Tarlinton DM, Kallies A, Corcoran LM. B and T cells collaborate in antiviral responses via IL-6, IL-21, and transcriptional activator and coactivator, Oct2 and OBF-1. ACTA ACUST UNITED AC 2012; 209:2049-64. [PMID: 23045607 PMCID: PMC3478936 DOI: 10.1084/jem.20111504] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transcriptional activator Oct2 and cofactor OBF-1 regulate B cell IL-6 to induce T cell production of IL-21, to support Tfh cell development in antiviral immunity. A strong humoral response to infection requires the collaboration of several hematopoietic cell types that communicate via antigen presentation, surface coreceptors and their ligands, and secreted factors. The proinflammatory cytokine IL-6 has been shown to promote the differentiation of activated CD4+ T cells into T follicular helper cells (TFH cells) during an immune response. TFH cells collaborate with B cells in the formation of germinal centers (GCs) during T cell–dependent antibody responses, in part through secretion of critical cytokines such as IL-21. In this study, we demonstrate that loss of either IL-6 or IL-21 has marginal effects on the generation of TFH cells and on the formation of GCs during the response to acute viral infection. However, mice lacking both IL-6 and IL-21 were unable to generate a robust TFH cell–dependent immune response. We found that IL-6 production in follicular B cells in the draining lymph node was an important early event during the antiviral response and that B cell–derived IL-6 was necessary and sufficient to induce IL-21 from CD4+ T cells in vitro and to support TFH cell development in vivo. Finally, the transcriptional activator Oct2 and its cofactor OBF-1 were identified as regulators of Il6 expression in B cells.
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Affiliation(s)
- Alex Karnowski
- Molecular Immunology Division and 2 Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
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13
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Kuo FT, Bentsi-Barnes IK, Barlow GM, Pisarska MD. Mutant Forkhead L2 (FOXL2) proteins associated with premature ovarian failure (POF) dimerize with wild-type FOXL2, leading to altered regulation of genes associated with granulosa cell differentiation. Endocrinology 2011; 152:3917-29. [PMID: 21862621 PMCID: PMC3176639 DOI: 10.1210/en.2010-0989] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Premature ovarian failure in the autosomal dominant disorder blepharophimosis-ptosis-epicanthus inversus is due to mutations in the gene encoding Forkhead L2 (FOXL2), producing putative truncated proteins. We previously demonstrated that FOXL2 is a transcriptional repressor of the steroidogenic acute regulatory (StAR), P450SCC (CYP11A), P450aromatase (CYP19), and cyclin D2 (CCND2) genes, markers of ovarian follicle proliferation and differentiation. Furthermore, we found that mutations of FOXL2 may regulate wild-type FOXL2, leading to loss of transcriptional repression of CYP19, similar to StAR. However, the regulatory mechanisms underlying these premature ovarian failure-associated mutations remain largely unknown. Therefore, we examined the effects of a FOXL2 mutant protein on the transcriptional repression of the CYP19 promoter by the full-length protein. We found that mutant FOXL2 exerts a dominant-negative effect on the repression of CYP19 by wild-type FOXL2. Both wild-type and mutant FOXL2 and can form homo- and heterodimers. We identified a minimal -57-bp human CYP19 promoter containing two potential FOXL2-binding regions and found that both wild-type and mutant FOXL2 can bind to either of these regions. Mutational analysis revealed that either site is sufficient for transcriptional repression by wild-type FOXL2, and the dominant-negative effect of mutant FOXL2, but these are eliminated when both sites are mutated. These findings confirm that mutant FOXL2 exerts a dominant-negative effect on wild-type FOXL2's activity as a transcriptional repressor of key genes in ovarian follicle differentiation and suggest that this is likely due to heterodimer formation and possibly also competition for DNA binding.
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Affiliation(s)
- Fang-Ting Kuo
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics/Gynecology, Cedars-Sinai Medical Center, 8635 West Third Street, Los Angeles, California 90048, USA
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14
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Puspasari N, Rowley SM, Gordon L, Lockhart PJ, Ioannou PA, Delatycki MB, Sarsero JP. Long range regulation of human FXN gene expression. PLoS One 2011; 6:e22001. [PMID: 21760943 PMCID: PMC3132285 DOI: 10.1371/journal.pone.0022001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 06/10/2011] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA) is the most common form of hereditary ataxia characterized by the presence of a GAA trinucleotide repeat expansion within the first intron of the FXN gene. The expansion inhibits FXN gene expression resulting in an insufficiency of frataxin protein. METHODOLOGY/PRINCIPAL FINDING In this study, computational analyses were performed on the 21.3 kb region upstream of exon 1 of the human FXN gene and orthologs from other species in order to identify conserved non-coding DNA sequences with potential regulatory functions. The conserved non-coding regions identified were individually analyzed in two complementing assay systems, a conventional luciferase reporter system and a novel Bacterial Artificial Chromosome (BAC)-based genomic reporter. The BAC system allows the evaluation of gene expression to be made in the context of its entire genomic locus and preserves the normal location and spacing of many regulatory elements which may be positioned over large distances from the initiation codon of the gene. CONCLUSIONS/SIGNIFICANCE The two approaches were used to identify a region of 17 bp located approximately 4.9 kb upstream of the first exon of the FXN gene that plays an important role in FXN gene expression. Modulation of FXN gene expression was found to be mediated by the action of the Oct-1 transcription factor at this site. A better understanding of cis-acting regulatory elements that control FXN gene expression has the potential to develop new strategies for the upregulation of the FXN gene as a therapy for FRDA.
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Affiliation(s)
- Novita Puspasari
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Simone M. Rowley
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Lavinia Gordon
- Bioinformatics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Paul J. Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Panos A. Ioannou
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Martin B. Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Clinical Genetics, Austin Health, Heidelberg, Victoria, Australia
| | - Joseph P. Sarsero
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
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15
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Zhao C, Inoue J, Imoto I, Otsuki T, Iida S, Ueda R, Inazawa J. POU2AF1, an amplification target at 11q23, promotes growth of multiple myeloma cells by directly regulating expression of a B-cell maturation factor, TNFRSF17. Oncogene 2007; 27:63-75. [PMID: 17621271 DOI: 10.1038/sj.onc.1210637] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Multiple myeloma (MM), a progressive hematological neoplasm, is thought to result from multiple genetic events affecting the terminal plasma cell. However, genetic aberrations related to MM are seldom reported. Using our in-house array-based comparative genomic hybridization system to locate candidate target genes with following their expression analysis, we identified POU2AF1 at 11q23.1 as a probable amplification target in MM cell lines. POU2AF1 is a B-cell-specific transcriptional co-activator, which interacts with octamer-binding transcription factors Oct-1 and Oct-2, and augments their function. Downregulation of POU2AF1 expression by specific small-interfering RNA (siRNA) inhibited MM cell growth, whereas ectopic expression of POU2AF1 promoted growth of MM cells. Among putative transcriptional targets for POU2AF1, B-cell maturation factor, TNFRSF17, enhanced its transcription by POU2AF1, and POU2AF1 directly bound to an octamer site within the 5' region of TNFRSF17. Expression level of TNFRSF17 was closely correlated with that of POU2AF1 in cell lines and primary samples of MM, and decreasing TNFRSF17 expression by means of TNFRSF17 siRNA inhibited MM cell growth. Taken together, our results suggest that POU2AF1, when activated by amplification or other mechanisms, may contribute to progression of MM by accelerating growth of MM cells through direct transactivation of one of its target genes, TNFRSF17.
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Affiliation(s)
- C Zhao
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo, Japan
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16
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Hikima JI, Lennard ML, Wilson MR, Miller NW, Warr GW. Regulation of the immunoglobulin heavy chain locus expression at the phylogenetic level of a bony fish: transcription factor interaction with two variant octamer motifs. Gene 2006; 377:119-29. [PMID: 16759823 DOI: 10.1016/j.gene.2006.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 03/15/2006] [Accepted: 03/24/2006] [Indexed: 10/24/2022]
Abstract
Transcriptional control of the IGH locus in teleosts is not fully understood, but evidence from catfish and zebrafish indicates major roles for octamer-binding (Oct) and E-protein transcription factors. A pair of variant octamer motifs in the Emu3' enhancer of the catfish has been shown to be particularly important in driving expression, justifying detailed study of their function. These octamer motifs were examined to determine if they bound Oct2 POU domains in monomeric or dimeric (PORE and MORE) configurations. While catfish Oct2 was shown to be capable of binding PORE and MORE motifs in dimeric conformation, the two octamer motifs in Emu3' bound Oct2 POU domains only in monomeric configuration. Catfish Oct2, when bound in this monomeric conformation, was shown to bend the DNA helix. The relative position of the two octamer motifs in Emu3' affected the activity of the enhancer, and moving the octamer motifs closer together by 5 bp greatly reduced the activity of the enhancer. This effect was not due to steric hindrance preventing the binding of Oct transcription factors to the two motifs, but rather was shown to be due to the disruption of an additional transcription factor binding site lying between the two octamer motifs.
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Affiliation(s)
- Jun-Ichi Hikima
- Medical University of South Carolina, Marine Biomedicine and Environmental Sciences Center and Department of Biochemistry and Molecular Biology, Charleston, 29425, USA
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17
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Abstract
BOB.1/OBF.1 is a lymphocyte-restricted transcriptional coactivator. It binds together with the Oct1 and Oct2 transcription factors to DNA and enhances their transactivation potential. Mice deficient for the transcriptional coactivator BOB.1/OBF.1 show several defects in differentiation, function and signaling of B cells. In search of BOB.1/OBF.1 regulated genes we identified Btk—a cytoplasmic tyrosine kinase—as a direct target of BOB.1/OBF.1. Analyses of the human as well as murine Btk promoters revealed a non-consensus octamer site close to the start site of transcription. Here we show that Oct proteins together with BOB.1/OBF.1 are able to form ternary complexes on these sites in vitro and in vivo. This in turn leads to the induction of Btk promoter activity in synergism with the transcription factor PU.1. Btk, like BOB.1/OBF.1, plays a critical role in B cell development and B cell receptor signalling. Therefore the down-regulation of Btk expression in BOB.1/OBF.1-deficient B cells could be related to the functional and developmental defects observed in BOB.1/OBF.1-deficient mice.
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Affiliation(s)
| | - Thomas Wirth
- To whom correspondence should be addressed. Tel: 0049 731 502 3262; Fax: 0049 731 502 2892;
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18
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Bartholdy B, Matthias P. Transcriptional control of B cell development and function. Gene 2004; 327:1-23. [PMID: 14960357 DOI: 10.1016/j.gene.2003.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Revised: 10/14/2003] [Accepted: 11/07/2003] [Indexed: 12/17/2022]
Abstract
The generation, development, maturation and selection of mammalian B lymphocytes is a complex process that is initiated in the embryo and proceeds throughout life to provide the organism an essential part of the immune system it requires to cope with pathogens. Transcriptional regulation of this highly complex series of events is a major control mechanism, although control is also exerted on all other layers, including splicing, translation and protein stability. This review summarizes our current understanding of transcriptional control of the well-studied murine B cell development, which bears strong similarity to its human counterpart. Animal and cell models with loss of function (gene "knock outs") or gain of function (often transgenes) have significantly contributed to our knowledge about the role of specific transcription factors during B lymphopoiesis. In particular, a large number of different transcriptional regulators have been linked to distinct stages of the life of B lymphocytes such as: differentiation in the bone marrow, migration to the peripheral organs and antigen-induced activation.
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Affiliation(s)
- Boris Bartholdy
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, PO Box 2543, Maulbeerstrasse 66, 4058 Basel, Switzerland
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Abstract
The transcriptional co-activator OCA-B [for Oct co-activator from B cells, also known as OBF-1 (OCT-binding factor-1) and Bob1] is not required for B-cell genesis but does regulate subsequent B-cell development and function. OCA-B deficient mice show strain-specific, partial blocks at multiple stages of B-cell maturation and a complete disruption of germinal center formation in all strains, causing humoral immune deficiency and susceptibility to infection. OCA-B probably exerts its effects through the regulation of octamer-motif controlled gene expression. The OCA-B gene encodes two proteins of distinct molecular weight, designated p34 and p35. The p34 isoform localizes in the nucleus, whereas the p35 isoform is myristoylated and is bound to the cytoplasmic membrane. p35 can traffic to the nucleus and probably activates octamer-dependent transcription, although this OCA-B isoform might regulate B cells through membrane-related signal transduction.
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Affiliation(s)
- Michael A Teitell
- Departments of Pathology and Pediatrics, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 675 Charles Young Drive South, Los Angeles, CA 90095, USA.
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