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Valle-Mendiola A, Gutiérrez-Hoya A, Soto-Cruz I. JAK/STAT Signaling and Cervical Cancer: From the Cell Surface to the Nucleus. Genes (Basel) 2023; 14:1141. [PMID: 37372319 DOI: 10.3390/genes14061141] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/13/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway constitutes a rapid signaling module from the cell surface to the nucleus, and activates different cellular responses, such as proliferation, survival, migration, invasion, and inflammation. When the JAK/STAT pathway is altered, it contributes to cancer progression and metastasis. STAT proteins play a central role in developing cervical cancer, and inhibiting the JAK/STAT signaling may be necessary to induce tumor cell death. Several cancers show continuous activation of different STATs, including cervical cancer. The constitutive activation of STAT proteins is associated with a poor prognosis and overall survival. The human papillomavirus (HPV) oncoproteins E6 and E7 play an essential role in cervical cancer progression, and they activate the JAK/STAT pathway and other signals that induce proliferation, survival, and migration of cancer cells. Moreover, there is a crosstalk between the JAK/STAT signaling cascade with other signaling pathways, where a plethora of different proteins activate to induce gene transcription and cell responses that contribute to tumor growth. Therefore, inhibition of the JAK/STAT pathway shows promise as a new target in cancer treatment. In this review, we discuss the role of the JAK/STAT pathway components and the role of the HPV oncoproteins associated with cellular malignancy through the JAK/STAT proteins and other signaling pathways to induce tumor growth.
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Affiliation(s)
- Arturo Valle-Mendiola
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
| | - Adriana Gutiérrez-Hoya
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
- Cátedra CONACYT, FES Zaragoza, National University of Mexico, Mexico City 09230, Mexico
| | - Isabel Soto-Cruz
- Molecular Oncology Laboratory, Cell Differentiation and Cancer Research Unit, FES Zaragoza, National University of Mexico, Batalla 5 de Mayo s/n, Colonia Ejército de Oriente, Mexico City 09230, Mexico
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Subramani A, Hite MEL, Garcia S, Maxwell J, Kondee H, Millican GE, McClelland EE, Seipelt-Thiemann RL, Nelson DE. Regulation of macrophage IFNγ-stimulated gene expression by the transcriptional coregulator CITED1. J Cell Sci 2023; 136:jcs260529. [PMID: 36594555 PMCID: PMC10112972 DOI: 10.1242/jcs.260529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/21/2022] [Indexed: 01/04/2023] Open
Abstract
Macrophages serve as a first line of defense against microbial pathogens. Exposure to interferon-γ (IFNγ) increases interferon-stimulated gene (ISG) expression in these cells, resulting in enhanced antimicrobial and proinflammatory activity. Although this response must be sufficiently vigorous to ensure the successful clearance of pathogens, it must also be carefully regulated to prevent tissue damage. This is controlled in part by CBP/p300-interacting transactivator with glutamic acid/aspartic acid-rich carboxyl-terminal domain 2 (CITED2), a transcriptional coregulator that limits ISG expression by inhibiting STAT1 and IRF1. Here, we show that the closely related Cited1 is an ISG, which is expressed in a STAT1-dependent manner, and that IFNγ stimulates the nuclear accumulation of CITED1 protein. In contrast to CITED2, ectopic CITED1 enhanced the expression of a subset of ISGs, including Ccl2, Ifit3b, Isg15 and Oas2. This effect was reversed in a Cited1-null cell line produced by CRISPR-based genomic editing. Collectively, these data show that CITED1 maintains proinflammatory gene expression during periods of prolonged IFNγ exposure and suggest that there is an antagonistic relationship between CITED proteins in the regulation of macrophage inflammatory function. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Aarthi Subramani
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Maria E. L. Hite
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Sarah Garcia
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Jack Maxwell
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Hursha Kondee
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Grace E. Millican
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
| | - Erin E. McClelland
- College of Osteopathic Medicine, Marian University, Indianapolis, IN 46222, USA
| | | | - David E. Nelson
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA
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Landau LJB, Fam BSDO, Yépez Y, Caldas-Garcia GB, Pissinatti A, Falótico T, Reales G, Schüler-Faccini L, Sortica VA, Bortolini MC. Evolutionary analysis of the anti-viral STAT2 gene of primates and rodents: Signature of different stages of an arms race. INFECTION GENETICS AND EVOLUTION 2021; 95:105030. [PMID: 34384937 DOI: 10.1016/j.meegid.2021.105030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/24/2021] [Accepted: 08/06/2021] [Indexed: 02/04/2023]
Abstract
STAT2 plays a strategic role in defending viral infection through the signaling cascade involving the immune system initiated after type I interferon release. Many flaviviruses target the inactivation or degradation of STAT2 as a strategy to impair this host's line of defense. Primates are natural reservoirs for a range of disease-causing flaviviruses (e.g., Zika, Dengue, and Yellow Fever virus), while rodents appear less susceptible. We analyzed the STAT2 coding sequence of 28 Rodentia species and 49 Primates species. Original data from 19 Platyrrhini species were sequenced for the SH2 domain of STAT2 and included in the analysis. STAT2 has many sites whose variation can be explained by positive selection, measurement by two methods (PALM indicated 12, MEME 61). Both evolutionary tests significantly marked sites 127, 731, 739, 766, and 780. SH2 is under evolutionary constraint but presents episodic positive selection events within Rodentia: in one of them, a moderately radical change (serine > arginine) at position 638 is found in Peromyscus species, and can be implicated in the difference in susceptibility to flaviviruses within Rodentia. Some other positively selected sites are functional such as 5, 95, 203, 251, 782, and 829. Sites 251 and 287 regulate the signaling mediated by the JAK-STAT2 pathway, while 782 and 829 create a stable tertiary structure of STAT2, facilitating its connection with transcriptional co-activators. Only three positively selected sites, 5, 95, and 203, are recognized members who act on the interface between STAT2 and flaviviruses NS5 protein. We suggested that due to the higher evolutionary rate, rodents are, at this moment, taking some advantage in the battle against infections for some well-known Flaviviridae, in particular when compared to primates. Our results point to dynamics that fit with a molecular evolutionary scenario shaped by a thought-provoking virus-host arms race.
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Affiliation(s)
- Luane Jandira Bueno Landau
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bibiana Sampaio de Oliveira Fam
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Yuri Yépez
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gabriela Barreto Caldas-Garcia
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Alcides Pissinatti
- Rio de Janeiro's Primatology Center (RJPC - INEA), Rio de Janeiro, RJ, Brazil
| | - Tiago Falótico
- School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, SP, Brazil
| | - Guillermo Reales
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Genética Médica Populacional, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Lavínia Schüler-Faccini
- Instituto Nacional de Genética Médica Populacional, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Vinicius Albuquerque Sortica
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Maria Cátira Bortolini
- Laboratório de Evolução Humana e Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Michalska A, Blaszczyk K, Wesoly J, Bluyssen HAR. A Positive Feedback Amplifier Circuit That Regulates Interferon (IFN)-Stimulated Gene Expression and Controls Type I and Type II IFN Responses. Front Immunol 2018; 9:1135. [PMID: 29892288 PMCID: PMC5985295 DOI: 10.3389/fimmu.2018.01135] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022] Open
Abstract
Interferon (IFN)-I and IFN-II both induce IFN-stimulated gene (ISG) expression through Janus kinase (JAK)-dependent phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT2. STAT1 homodimers, known as γ-activated factor (GAF), activate transcription in response to all types of IFNs by direct binding to IFN-II activation site (γ-activated sequence)-containing genes. Association of interferon regulatory factor (IRF) 9 with STAT1–STAT2 heterodimers [known as interferon-stimulated gene factor 3 (ISGF3)] or with STAT2 homodimers (STAT2/IRF9) in response to IFN-I, redirects these complexes to a distinct group of target genes harboring the interferon-stimulated response element (ISRE). Similarly, IRF1 regulates expression of ISGs in response to IFN-I and IFN-II by directly binding the ISRE or IRF-responsive element. In addition, evidence is accumulating for an IFN-independent and -dependent role of unphosphorylated STAT1 and STAT2, with or without IRF9, and IRF1 in basal as well as long-term ISG expression. This review provides insight into the existence of an intracellular amplifier circuit regulating ISG expression and controlling long-term cellular responsiveness to IFN-I and IFN-II. The exact timely steps that take place during IFN-activated feedback regulation and the control of ISG transcription and long-term cellular responsiveness to IFN-I and IFN-II is currently not clear. Based on existing literature and our novel data, we predict the existence of a multifaceted intracellular amplifier circuit that depends on unphosphorylated and phosphorylated ISGF3 and GAF complexes and IRF1. In a combinatorial and timely fashion, these complexes mediate prolonged ISG expression and control cellular responsiveness to IFN-I and IFN-II. This proposed intracellular amplifier circuit also provides a molecular explanation for the existing overlap between IFN-I and IFN-II activated ISG expression.
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Affiliation(s)
- Agata Michalska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Katarzyna Blaszczyk
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Joanna Wesoly
- Laboratory of High Throughput Technologies, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Hans A R Bluyssen
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
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Liu X, Chen J, Zhang J. AdipoR1-mediated miR-3908 inhibits glioblastoma tumorigenicity through downregulation of STAT2 associated with the AMPK/SIRT1 pathway. Oncol Rep 2017; 37:3387-3396. [PMID: 28440504 DOI: 10.3892/or.2017.5589] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 04/07/2017] [Indexed: 11/06/2022] Open
Abstract
A prospective method of treatment for cancer is to inhibit oncogene signaling pathways with microRNA (miRNA or miR). In the present study, whether the expression of STAT2, AdipoR1/AMPK/SIRT1 pathway of glioma is regulated by miR-3908 was explored. To confirm whether the predicted miR-3908 is matched with STAT2 and AdipoR1, 3'UTR luciferase activity of STAT2 and AdipoR1 was assessed. In the presence of the mimics or inhibitors of miR-3908, cell function of glioma cells, such as proliferation, growth, migration, invasion and apoptosis were analyzed. The expression of AdipoR1 and its downstream AMPK/SIRT1 pathway proteins or STAT2 were examined. Luciferase reporter analysis showed that miR-3908 directly target STAT2 and AdipoR1. miR-3908 suppressed expression of STAT2 or AdipoR1 and downregulated AdipoR1 pathway genes, including AMPK, p-AMPK and SIRT1. miR-3908 inhibited tumorigenicity, migration, growth and invasion in glioma cell lines U251 and U87 as well as increased apoptosis of these cells. The pathways related to tumorigenicity and tumor progression, STAT2 and AdipoR1/AMPK/SIRT1 could be restrained by miR-3908. In conclusion, restoration of miR-3908 expression induced suppression of cancer progression and glioblastoma tumorigenicity. The present study discovered novel tumorigenesis associated with miR-3908, which may represent a new target in treatment for glioblastoma.
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Affiliation(s)
- Xiangming Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China
| | - Jinglong Chen
- Department of Oncology, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
| | - Jinqian Zhang
- Department of Laboratory Medicine, The Second People's Hospital of Guangdong Province, Southern Medical University, Guangzhou, Guangdong 510317, P.R. China
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Steen HC, Gamero AM. The role of signal transducer and activator of transcription-2 in the interferon response. J Interferon Cytokine Res 2012; 32:103-10. [PMID: 22280068 DOI: 10.1089/jir.2011.0099] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The signal transducer and activator of transcription-2 (STAT2) was discovered as a cellular component of the DNA binding complex known as interferon (IFN) stimulated gene factor-3. Numerous studies have confirmed that STAT2 operates as a positive regulator in the transcriptional activation response elicited by IFNs. In this article, we highlight the progress made in elucidating the pivotal role of STAT2 in driving the expression of IFN-induced genes, innate antiviral immunity, apoptosis, and cancer. A better understanding of the functional role of STAT2 in the IFN response and how STAT2 is regulated will uncover new clues to its role in diseases.
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Affiliation(s)
- Håkan C Steen
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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7
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Du Z, Fan M, Kim JG, Eckerle D, Lothstein L, Wei L, Pfeffer LM. Interferon-resistant Daudi cell line with a Stat2 defect is resistant to apoptosis induced by chemotherapeutic agents. J Biol Chem 2009; 284:27808-27815. [PMID: 19687011 DOI: 10.1074/jbc.m109.028324] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Interferon-alpha (IFNalpha) has shown promise in the treatment of various cancers. However, the development of IFN resistance is a significant drawback. Using conditions that mimic in vivo selection of IFN-resistant cells, the RST2 IFN-resistant cell line was isolated from the highly IFN-sensitive Daudi human Burkitt lymphoma cell line. The RST2 cell line was resistant to the antiviral, antiproliferative, and gene-induction actions of IFNalpha. Although STAT2 mRNA was present, STAT2 protein expression was deficient in RST2 cells. A variant STAT2 mRNA, which resulted from alternative splicing within the intron between exon 19 and 20, was expressed in several human cell lines but at relatively high levels in RST2 cells. Most importantly, the RST2 line showed an intrinsic resistance to apoptosis induced by a number of chemotherapeutic agents (camptothecin, staurosporine, and doxorubicin). Expression of STAT2 in RST2 cells not only rescued their sensitivity to the biological activities of IFNs but also restored sensitivity to apoptosis induced by these chemotherapeutic agents. The intrinsic resistance of the RST2 cells to IFN as well as chemotherapeutic agents adds a new dimension to our knowledge of the role of STAT2 as it relates to not only biological actions of IFN but also resistance to chemotherapy-induced apoptosis.
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Affiliation(s)
- Ziyun Du
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Meiyun Fan
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Jong-Gwan Kim
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Dara Eckerle
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Leonard Lothstein
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Lai Wei
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163
| | - Lawrence M Pfeffer
- Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center and Center for Cancer Research, Memphis, Tennessee 38163.
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8
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Collet B, Ganne G, Bird S, Collins CM. Isolation and expression profile of a gene encoding for the Signal Transducer and Activator of Transcription STAT2 in Atlantic salmon (Salmo salar). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2009; 33:821-829. [PMID: 19428483 DOI: 10.1016/j.dci.2009.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2008] [Revised: 01/21/2009] [Accepted: 01/25/2009] [Indexed: 05/27/2023]
Abstract
Signal Transducer and Activator of Transcription (STAT)-2 is a molecule involved in the type I interferon (IFN) signalling pathway. The full length cDNA sequence of Atlantic salmon (Salmo salar) ssSTAT2 was determined and phylogenetic analysis of the amino acid sequence grouped this novel salmon gene to the STAT2 clade. This represents the first fish STAT2 report. The gene encodes for a 802 aa polypeptide that has 38% identity to the human or murine STAT2. The expression was monitored by qPCR in the kidney of animals over the time of infection with the Infectious Salmon Anaemia Virus (ISAV) and in TO cells infected with Infectious Pancreatic Necrosis Virus (IPNV) or with the Salmon Alphavirus (SAV). SAV and ISAV induced an approximate 10-fold increase in the level of expression of ssSTAT2 gene whilst IPNV only induced a 1.5-fold increase.
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Molenaar A, Wheeler TT, McCracken JY, Seyfert HM. TheSTAT3-encoding gene resides within the 40 kbp gap between theSTAT5A- andSTAT5B-encoding genes in cattle. Anim Genet 2008. [DOI: 10.1111/j.1365-2052.2000.00662.pp.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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NFAR-1 and -2 modulate translation and are required for efficient host defense. Proc Natl Acad Sci U S A 2008; 105:4173-8. [PMID: 18337511 DOI: 10.1073/pnas.0711222105] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We report here that the alternatively spliced nuclear factors associated with double-stranded RNA, NFAR-1 (90 kDa) and -2 (110 kDa), are involved in retaining cellular transcripts in intranuclear foci and can regulate the export of mRNA to the cytoplasm. Furthermore, the NFAR proteins were found to remain associated with exported ribonucleoprotein complexes. Loss of NFAR function, which was embryonic-lethal, caused an increase in protein synthesis rates, an effect augmented by the presence of the mRNA export factors TAP, p15, or Rae1. Significantly, NFAR depletion in normal murine fibroblasts rendered these cells dramatically susceptible to vesicular stomatitis virus replication. Collectively, our data demonstrate that the NFARs exert influence on mRNA trafficking and the modulation of translation rates and may constitute an innate immune translational surveillance mechanism important in host defense countermeasures against virus infection.
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Oelschlegel R, Krüger DH, Rang A. MxA-independent inhibition of Hantaan virus replication induced by type I and type II interferon in vitro. Virus Res 2007; 127:100-5. [PMID: 17482705 DOI: 10.1016/j.virusres.2007.03.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 02/04/2023]
Abstract
Interferons (IFN) induce an antiviral state against Hantaan virus (HTNV) but the mechanisms responsible for inhibition are unclear. The IFN-inducible MxA is discussed to be important for control of infections with hantaviruses. To characterize the role of endogenous MxA, the inhibition of HTNV induced by type I and type II IFNs was compared in Vero and A549 cells. IFNalpha and IFNgamma reduced production of infectious virions, viral RNA, and nucleocapsid protein with the same efficiency, although expression of MxA protein was detectable only in IFNalpha-treated A549 cells. Furthermore, knock down of MxA expression did not impair IFNalpha-induced inhibition. Thus, inhibition of HTNV induced by type I and type II IFNs did not dependent on expression of endogenous MxA. Taken together, these data suggest that MxA endogenously expressed in response to type I or type II IFNs does not play a pivotal role for the antiviral state against HTNV and that there is more than one mechanism by which cellular defences block hantavirus replication.
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Affiliation(s)
- Robin Oelschlegel
- Institute of Virology, Helmut-Ruska-Haus, University Hospital Charité, Charité Campus Mitte, D-10098 Berlin, Germany.
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12
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Theodosiou M, Monaghan JR, Spencer ML, Voss SR, Noonan DJ. Isolation and characterization of axolotl NPDC-1 and its effects on retinoic acid receptor signaling. Comp Biochem Physiol B Biochem Mol Biol 2007; 147:260-70. [PMID: 17331771 PMCID: PMC2683337 DOI: 10.1016/j.cbpb.2007.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 01/19/2007] [Accepted: 01/19/2007] [Indexed: 12/31/2022]
Abstract
Retinoic acid, a key morphogen in early vertebrate development and tissue regeneration, mediates its effects through the binding of receptors that act as ligand-induced transcription factors. These binding events function to recruit an array of transcription co-regulatory proteins to specific gene promoters. One such co-regulatory protein, neuronal proliferation and differentiation control-1 (NPDC-1), is broadly expressed during mammalian development and functions as an in vitro repressor of retinoic acid receptor (RAR)-mediated transcription. To obtain comparative and developmental insights about NPDC-1 function, we cloned the axolotl (Ambystoma mexicanum) orthologue and measured transcript abundances among tissues sampled during the embryonic and juvenile phases of development, and also during spinal cord regeneration. Structurally, the axolotl orthologue of NPDC-1 retained sequence identity to mammalian sequences in all functional domains. Functionally, we observed that axolotl NPDC-1 mRNA expression peaked late in embryogenesis, with highest levels of expression occurring during the time of limb development, a process regulated by retinoic acid signaling. Also similar to what has been observed in mammals, axolotl NPDC-1 directly interacts with axolotl RAR, modulates axolotl RAR DNA binding, and represses cell proliferation and axolotl RAR-mediated gene transcription. These data justify axolotl as a model to further investigate NPDC-1 and its role in regulating retinoic acid signaling.
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Affiliation(s)
- Maria Theodosiou
- : Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - James R Monaghan
- : Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - Michael L Spencer
- : Division of Developmental Biology, Cincinnati Children’s Hospital Research Foundation, Cincinnati, OH 45229, USA
| | - S Randal Voss
- : Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - Daniel J Noonan
- : Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
- Corresponding Author: Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone Ave., Lexington, KY 40536, USA, Phone: (859) 257-7498, Fax: (859) 323-1037, e-mail:
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Xiao S, Li D, Zhu HQ, Song MG, Pan XR, Jia PM, Peng LL, Dou AX, Chen GQ, Chen SJ, Chen Z, Tong JH. RIG-G as a key mediator of the antiproliferative activity of interferon-related pathways through enhancing p21 and p27 proteins. Proc Natl Acad Sci U S A 2006; 103:16448-53. [PMID: 17050680 PMCID: PMC1637602 DOI: 10.1073/pnas.0607830103] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The RIG-G gene, originally isolated from an acute promyelocytic leukemia cell line NB4, codes for a 60-kDa cytoplasmic protein that is induced by all-trans retinoic acid (ATRA) treatment along with the induction of morphological differentiation of NB4 cells. Here, we provide evidence that ectopic expression of Rig-G in U937 cells can lead to a significant accumulation of cells at G(1)/S transition. Growth arrest seems to occur by modulating several major cell cycle regulatory players. Interestingly, Rig-G alters JAB1 cellular distribution through interacting with this protein and increases the intracellular level of p27 by preventing it from the JAB-1-dependent and ubiquitin/proteasome-mediated degradation. Furthermore, we demonstrate a role of Rig-G for c-myc down-regulation that results in an up-regulation of p21, tightly associated with cell cycle arrest. In addition, our studies reveal that Rig-G is a direct target of STAT1, a key transcription factor in regulating IFN responses, and may be one of the first experimentally proven molecular mediators for the antiproliferative effect of IFN-alpha. Considering that IFN-alpha and ATRA synergistically inhibit growth along the intracellular pathways triggered by the two compounds in many cell types, we suggest that Rig-G may also represent one of the key molecular nodes of signaling cross-talk between ATRA and IFN-alpha.
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Affiliation(s)
- Shu Xiao
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Dong Li
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Hai-Qing Zhu
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Man-Gen Song
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Xiao-Rong Pan
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Pei-Min Jia
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Lin-Ling Peng
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Ai-Xia Dou
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Guo-Qiang Chen
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Sai-Juan Chen
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Zhu Chen
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
- To whom correspondence may be addressed. E-mail:
or
| | - Jian-Hua Tong
- Shanghai Institute of Hematology and State Key Laboratory of Medical Genomics, Rui Jin Hospital, Health Science Center, Shanghai Institutes for Biological Sciences and Graduates School, Chinese Academy of Sciences and School of Medicine, Shanghai Jiao Tong University, 197 Rui Jin Road II, Shanghai 200025, China; and Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
- To whom correspondence may be addressed. E-mail:
or
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14
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Hoey T, Zhang S, Schmidt N, Yu Q, Ramchandani S, Xu X, Naeger LK, Sun YL, Kaplan MH. Distinct requirements for the naturally occurring splice forms Stat4alpha and Stat4beta in IL-12 responses. EMBO J 2003; 22:4237-48. [PMID: 12912921 PMCID: PMC175783 DOI: 10.1093/emboj/cdg393] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Signal transducer and activator of transcription (Stat)4 is a signaling molecule required for normal responses to interleukin-12 (IL-12) and is critically involved in inflammatory responses. We have isolated an alternatively spliced isoform of Stat4, termed Stat4beta, which lacks 44 amino acids at the C-terminus, encompassing the putative transcriptional activation domain. To assess the in vivo roles of these Stat4 isoforms, we generated transgenic Stat4-deficient mice expressing Stat4alpha or Stat4beta. Our results indicate that T-cell-specific expression of Stat4alpha or Stat4beta can mediate many aspects of IL-12 signaling including the differentiation of Th1 cells. However, Stat4alpha is required for normal levels of IL-12-induced interferon-gamma production from Th1 cells. Microarray analysis identified 98 genes induced by both Stat4 isoforms, 32 genes induced only by Stat4alpha and 29 genes induced only by Stat4beta. Some induced genes correlate with specific functions including the ability of Stat4beta, but not Stat4alpha, to mediate IL-12-stimulated proliferation. Thus, Stat4alpha and Stat4beta have distinct roles in mediating responses to IL-12.
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Affiliation(s)
- Timothy Hoey
- Tularik, Inc., South San Francisco, CA 94080, USA
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15
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Frank DA. StAT signaling in cancer: insights into pathogenesis and treatment strategies. Cancer Treat Res 2003; 115:267-91. [PMID: 12613201 DOI: 10.1007/0-306-48158-8_11] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- David A Frank
- Department of Adult Oncology, Dana-Farber Cancer Institute, Departments of Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
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16
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Sung SC, Fan TJ, Chou CM, Leu JH, Hsu YL, Chen ST, Hsieh YC, Huang CJ. Genomic structure, expression and characterization of a STAT5 homologue from pufferfish (Tetraodon fluviatilis). EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:239-52. [PMID: 12605675 DOI: 10.1046/j.1432-1033.2003.03380.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The STAT5 (signal transducer and activator of transcription 5) gene was isolated and characterized from a round-spotted pufferfish genomic library. This gene is composed of 19 exons spanning 11 kb. The full-length cDNA of Tetraodon fluviatilis STAT5 (TfSTAT5) contains 2461 bp and encodes a protein of 785 amino acid residues. From the amino acid sequence comparison, TfSTAT5 is most similar to mouse STAT5a and STAT5b with an overall identity of 76% and 78%, respectively, and has < 35% identity with other mammalian STATs. The exon/intron junctions of the TfSTAT5 gene were almost identical to those of mouse STAT5a and STAT5b genes, indicating that these genes are highly conserved at the levels of amino acid sequence and genomic structure. To understand better the biochemical properties of TfSTAT5, a chimeric STAT5 was generated by fusion of the kinase-catalytic domain of carp Janus kinase 1 (JAK1) to the C-terminal end of TfSTAT5. The fusion protein was expressed and tyrosine-phosphorylated by its kinase domain. The fusion protein exhibits specific DNA-binding and transactivation potential toward an artificial fish promoter as well as authentic mammalian promoters such as the beta-casein promoter and cytokine inducible SH2 containing protein (CIS) promoter when expressed in both fish and mammalian cells. However, TfSTAT5 could not induce the transcription of beta-casein promoter via rat prolactin and Nb2 prolactin receptor. To our knowledge, this is the first report describing detailed biochemical characterization of a STAT protein from fish.
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Affiliation(s)
- Shu-Chiun Sung
- Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
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17
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Wong LH, Sim H, Chatterjee-Kishore M, Hatzinisiriou I, Devenish RJ, Stark G, Ralph SJ. Isolation and characterization of a human STAT1 gene regulatory element. Inducibility by interferon (IFN) types I and II and role of IFN regulatory factor-1. J Biol Chem 2002; 277:19408-17. [PMID: 11909852 DOI: 10.1074/jbc.m111302200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The transcription factor STAT1 plays a pivotal role in signal transduction of type I and II interferons (IFNs). STAT1 activation leads to changes in expression of key regulatory genes encoding caspases and cell cycle inhibitors. Deficient STAT1 expression in human cancer cells and virally mediated inhibition of STAT1 function have been associated with cellular resistance to IFNs and mycobacterial infection in humans. Thus, given the relative importance of STAT1, we isolated and characterized a human STAT1 intronic enhancer region displaying IFN-regulated activity. Functional analyses by transient expression identified a repressor region and type I and II IFN-inducible elements within the STAT1 enhancer sequence. A candidate IRF-E/GAS/IRF-E (IGI) sequence containing GAAANN nucleotide repeats was shown by gel shift assay to bind to IFN regulatory factor-1 (IRF-1), but not to IFN-stimulated gene factor-3 (ISGF-3) or STAT1-3. An additional larger IGI-binding complex containing IRF-1 was identified. Mutation of the GAAANN repeats within the IGI DNA element eliminated IRF-1 binding and the IFN-regulated activity of the STAT1 intronic enhancer region. Transfection of the IFN-resistant MM96 cell line to express increased levels of IRF-1 protein also elevated STAT1, STAT2, and p48/IRF-9 expression and enhanced cellular responsiveness to IFN-beta. Reciprocating regulation between IRF-1 and STAT1 genes and encoded proteins indicates that an intracellular amplifier circuit exists controlling cellular responsiveness to the IFNs.
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MESH Headings
- Amino Acid Motifs
- Base Sequence
- Binding Sites
- Blotting, Northern
- Blotting, Western
- Chromosome Mapping
- Chromosomes, Artificial, Yeast
- Chromosomes, Human, Pair 2
- DNA, Complementary/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Dose-Response Relationship, Drug
- Enhancer Elements, Genetic
- Exons
- Genes, Reporter
- Genetic Vectors
- Humans
- Interferon Regulatory Factor-1
- Interferon Type I/pharmacology
- Interferon-gamma/pharmacology
- Introns
- Luciferases/metabolism
- Models, Genetic
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation
- Phosphoproteins/metabolism
- Polymerase Chain Reaction
- Protein Binding
- STAT1 Transcription Factor
- Time Factors
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription, Genetic
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- Lee H Wong
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia
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18
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Choi Y, Johnson GA, Burghardt RC, Berghman LR, Joyce MM, Taylor KM, Stewart MD, Bazer FW, Spencer TE. Interferon regulatory factor-two restricts expression of interferon-stimulated genes to the endometrial stroma and glandular epithelium of the ovine uterus. Biol Reprod 2001; 65:1038-49. [PMID: 11566724 DOI: 10.1095/biolreprod65.4.1038] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Interferon tau (IFNtau) is the signal for maternal recognition of pregnancy in ruminants. The positive effects of IFNtau on IFN-stimulated gene (ISG) expression are mediated by ISG factor 3 (ISGF3), which is composed of signal transducer and activator of transcription (Stat) 1, Stat 2, and IFN regulatory factor-9 (IRF-9), and by gamma-activated factor (GAF), which is a Stat 1 homodimer. Induction of ISGs, such as ISG17 and 2',5'-oligoadenylate synthetase, by IFNtau during pregnancy is limited to the endometrial stroma (S) and glandular epithelium (GE) of the ovine uterus. The IRF-2, a potent transcriptional repressor of ISG expression, is expressed in the luminal epithelium (LE). This study determined effects of the estrous cycle, pregnancy, and IFNtau on expression of Stat 1, Stat 2, IRF-9, IRF-1, and IRF-2 genes in the ovine endometrium. In cyclic ewes, Stat 1, Stat 2, IRF-1, and IRF-9 mRNA and protein were detected at low levels in the S and GE. During pregnancy, expression of these genes increased only in the S and GE. Expression of IRF-2 was detected only in the LE and superficial GE (sGE) of both cyclic and pregnant ewes. In cyclic ewes, intrauterine administration of IFNtau stimulated Stat 1, Stat 2, IRF-9, and IRF-1 expression in the endometrium. Ovine IRF-2 repressed transcriptional activity driven by IFN-stimulated response elements that bind ISGF3, but not by gamma-activation sequences that bind GAF. These results suggest that IRF-2 in the LE and sGE restricts IFNtau induction of ISGs to the S and GE. In the S and GE, IFNtau hyperactivation of ISG expression likely involves formation and actions of the transcription factors ISGF3 and, perhaps, IRF-1.
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Affiliation(s)
- Y Choi
- Center for Animal Biotechnology and Genomics, Department of Animal Science, Texas A&M University, College Station, Texas 77843, USA
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19
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Affiliation(s)
- J D Farrar
- Dept of Pathology and Center for Immunology, Howard Hughes Medical Institute, Washington University School of Medicine, St Louis, MO 63110, USA
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20
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Molenaar A, Wheeler TT, McCracken JY, Seyfert HM. The STAT3-encoding gene resides within the 40 kbp gap between the STAT5A- and STAT5B-encoding genes in cattle. Anim Genet 2000; 31:339-40. [PMID: 11105222 DOI: 10.1046/j.1365-2052.2000.00662.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- A Molenaar
- Ruakura Research Centre, Hamilton, New Zealand
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21
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Farrar JD, Smith JD, Murphy TL, Leung S, Stark GR, Murphy KM. Selective loss of type I interferon-induced STAT4 activation caused by a minisatellite insertion in mouse Stat2. Nat Immunol 2000; 1:65-9. [PMID: 10881177 DOI: 10.1038/76932] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The use of murine systems to model pathogen-induced human diseases presumes that general immune mechanisms between these species are conserved. One important immunoregulatory mechanism involves linkage of innate and adaptive immunity to direct the development of T helper subsets, for example toward subset 1 (TH1) development through STAT4 activation. In analyzing type I interferon signaling, we uncovered a difference between murine and human cells which may affect how these two species control linkage between innate and adaptive immunity. We show that in humans, type I interferons induce TH1 development and can activate STAT4 by recruitment to the IFN-alpha receptor complex specifically via the carboxy-terminus of STAT2. However, the mouse Stat2 gene harbors a minisatellite insertion that has altered the carboxy-terminus and selectively disrupted its capacity to activate STAT4, but not other STATs. This defect in murine Stat2 suggests that the signals leading to STAT4 activation and TH1 development in CD4+ T cells are different between mice and humans.
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Affiliation(s)
- J D Farrar
- Department of Pathology and Center for Immunology, Howard Hughes Medical Institute, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO 63110, USA
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22
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Farrar JD, Smith JD, Murphy TL, Murphy KM. Recruitment of Stat4 to the human interferon-alpha/beta receptor requires activated Stat2. J Biol Chem 2000; 275:2693-7. [PMID: 10644731 DOI: 10.1074/jbc.275.4.2693] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stat4 activation is involved in differentiation of type 1 helper (Th1) T cells. Although Stat4 is activated by interleukin (IL)-12 in both human and murine T cells, Stat4 is activated by interferon (IFN)-alpha only in human, but not murine, CD4(+) T cells. This species-specific difference in cytokine activation of Stat4 underlies critical differences in Th1 development in response to cytokines and is important to the interpretation of murine models of immunopathogenesis. Here, we sought to determine the mechanism of Stat4 recruitment and activation by the human IFN-alpha receptor. Analysis of phosphopeptide binding analysis suggests that Stat4 does not interact directly with tyrosine-phosphorylated amino acid residues within the cytoplasmic domains of either of the subunits of the IFN-alpha receptor complex. Expression of murine Stat4 in the Stat1-deficient U3A and the Stat2-deficient U6A cell lines shows that IFN-alpha-induced Stat4 phosphorylation requires the presence of activated Stat2 but not Stat1. Thus, in contrast to the direct recruitment of Stat4 by the IL-12 receptor, Stat4 activation by the human IFN-alpha receptor occurs through indirect recruitment by intermediates involving Stat2.
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Affiliation(s)
- J D Farrar
- Department of Pathology, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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23
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Didcock L, Young DF, Goodbourn S, Randall RE. The V protein of simian virus 5 inhibits interferon signalling by targeting STAT1 for proteasome-mediated degradation. J Virol 1999; 73:9928-33. [PMID: 10559305 PMCID: PMC113042 DOI: 10.1128/jvi.73.12.9928-9933.1999] [Citation(s) in RCA: 361] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
To replicate in vivo, viruses must circumvent cellular antiviral defense mechanisms, including those induced by the interferons (IFNs). Here we demonstrate that simian virus 5 (SV5) blocks IFN signalling in human cells by inhibiting the formation of the IFN-stimulated gene factor 3 and gamma-activated factor transcription complexes that are involved in activating IFN-alpha/beta- and IFN-gamma-responsive genes, respectively. SV5 inhibits the formation of these complexes by specifically targeting STAT1, a component common to both transcription complexes, for proteasome-mediated degradation. Expression of the SV5 structural protein V, in the absence of other virus proteins, also inhibited IFN signalling and induced the degradation of STAT1. Following infection with SV5, STAT1 was degraded in the absence of virus protein synthesis and remained undetectable for up to 4 days postinfection. Furthermore, STAT1 was also degraded in IFN-pretreated cells, even though the cells were in an antiviral state. Since pretreatment of cells with IFN delayed but did not prevent virus replication and protein synthesis, these observations suggest that following infection of IFN-pretreated cells, SV5 remains viable within the cells until they eventually go out of the antiviral state.
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Affiliation(s)
- L Didcock
- School of Biology, University of St. Andrews, Fife, Scotland KY16 9TS, United Kingdom
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24
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Karpf AR, Peterson PW, Rawlins JT, Dalley BK, Yang Q, Albertsen H, Jones DA. Inhibition of DNA methyltransferase stimulates the expression of signal transducer and activator of transcription 1, 2, and 3 genes in colon tumor cells. Proc Natl Acad Sci U S A 1999; 96:14007-12. [PMID: 10570189 PMCID: PMC24181 DOI: 10.1073/pnas.96.24.14007] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inhibitors of DNA methyltransferase, typified by 5-aza-2'-deoxycytidine (5-Aza-CdR), induce the expression of genes transcriptionally down-regulated by de novo methylation in tumor cells. We utilized gene expression microarrays to examine the effects of 5-Aza-CdR treatment in HT29 colon adenocarcinoma cells. This analysis revealed the induction of a set of genes that implicated IFN signaling in the HT29 cellular response to 5-Aza-CdR. Subsequent investigations revealed that the induction of this gene set correlates with the induction of signal transducer and activator of transcription (STAT) 1, 2, and 3 genes and their activation by endogenous IFN-alpha. These observations implicate the induction of the IFN-response pathway as a major cellular response to 5-Aza-CdR and suggests that the expression of STATs 1, 2, and 3 can be regulated by DNA methylation. Consistent with STAT's limiting cell responsiveness to IFN, we found that 5-Aza-CdR treatment sensitized HT29 cells to growth inhibition by exogenous IFN-alpha2a, indicating that 5-Aza-CdR should be investigated as a potentiator of IFN responsiveness in certain IFN-resistant tumors.
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Affiliation(s)
- A R Karpf
- The Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
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25
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Abstract
Studies using both transgenic mice and transfected mammary epithelial cells have established that composite response elements containing multiple binding sites for several transcription factors mediate the hormonal and developmental regulation of milk protein gene expression. Activation of signal transduction pathways by lactogenic hormones and cell-substratum interactions activate transcription factors and change chromatin structure and milk protein gene expression. The casein promoters have binding sites for signal transducers and activators of transcription 5, Yin Yang 1, CCAAT/enhancer binding protein, and the glucocorticoid receptor. The whey protein gene promoters have binding sites for nuclear factor I, as well as the glucocorticoid receptor and the signal transducers and activators of transcription 5. The functional importance of some of these factors in mammary gland development and milk protein gene expression has been elucidated by studying mice in which some of these factors have been deleted.
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Affiliation(s)
- J M Rosen
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030-3498, USA.
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26
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Pelicano L, Brumpt C, Pitha PM, Chelbi-Alix MK. Retinoic acid resistance in NB4 APL cells is associated with lack of interferon alpha synthesis Stat1 and p48 induction. Oncogene 1999; 18:3944-53. [PMID: 10435617 DOI: 10.1038/sj.onc.1202802] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the t(15;17) acute promyelocytic leukaemia (APL), all trans-retinoic (RA) treatment induces maturation leading to clinically complete but not durable remission, as RA resistance develops in the treated patients as well as in vitro. RA and interferons (IFNs) are known inhibitors of proliferation in various cells including those from APL. In this report, we show that they can act cooperatively to inhibit growth and to induce differentiation of NB4 cells but not of two RA-resistant NB4 derived cell lines, NB4-R1 and NB4-R2. However, the resistant cell lines respond to IFN. In NB4 cells, RA increases the expression of Stat1, p48 and IRF-1, three transcription factors playing a central role in the IFN response and induces the synthesis and the secretion of IFN alpha. RA-induced IFN alpha seems to play a role in inhibition of NB4 cell growth but not in their differentiation. In the resistant cells, NB4-R1 and NB4-R2, both the induction of IFN and the increase of Statl and p48 expression by RA are completely blocked. In contrast, IRF-1 mRNA and protein expressions are induced in the three cell lines. This suggests that increase of IRF-1 expression is not sufficient for IFN induction. Our results identify some defects linked to RA-resistance in APL and support the hypothesis that RA-induced Stat1 expression and IFN secretion may be one of the mechanisms mediating growth inhibition by RA.
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Affiliation(s)
- L Pelicano
- CNRS, UPR 9051, Hôpital St. Louis, Paris, France
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27
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Grimley PM, Dong F, Rui H. Stat5a and Stat5b: fraternal twins of signal transduction and transcriptional activation. Cytokine Growth Factor Rev 1999; 10:131-57. [PMID: 10743504 DOI: 10.1016/s1359-6101(99)00011-8] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Stat5a and Stat5b are discretely encoded transcription factors that mediate signals for a broad spectrum of cytokines. Their activation is often an integral component of redundant cytokine signal cascades involving complex cross-talk and pleiotropic gene regulation by Stat5 has been implicated in cellular functions of proliferation, differentiation and apoptosis with relevance to processes of hematopoiesis and immunoregulation, reproduction, and lipid metabolism. Although Stat5a and Stat5b show peptide sequence similarities of > 90%, targeted gene disruptions in mice yield distinctive phenotypes. Prolactin-directed mammary gland maturation fails without functional Stat5a, while disruption of Stat5b in males mitigates growth hormone effects on hepatic function and body mass. The molecular basis for this biologic dichotomy is probably multifaceted. Limited structural dissimilarities between the Stat5a and Stat5b transactivation domains, or subtle differences in the DNA-binding affinities of Stat5 dimer pairs undoubtedly influence gene regulation, but cell-dependent asymmetries in availability of phosphorylated Stat5 can be an underlying factor. Differences in serine phosphorylation(s) of Stat5a and Stat5b, or Stat5 associations with adaptor proteins or co-transcription factors are other potential sources of functional disparity and the signal amplitude, frequency or duration also can be significant. In addition to Stat5 signal attenuation by phosphatase actions or classical feedback inhibition, truncated forms of Stat5 lacking in transactivation capacity may compete upstream for activation and diminish access of full length molecules to DNA binding sites.
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Affiliation(s)
- P M Grimley
- Department of Pathology, F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20854, USA
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28
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Patel BK, Keck CL, O'Leary RS, Popescu NC, LaRochelle WJ. Localization of the human stat6 gene to chromosome 12q13.3-q14.1, a region implicated in multiple solid tumors. Genomics 1998; 52:192-200. [PMID: 9782085 DOI: 10.1006/geno.1998.5436] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stat6 signaling pathways have been correlated with functional responses induced by IL-4 and PDGF that may play a role in human malignancy. Utilizing fluorescence in situ hybridization, we mapped the human Stat6 gene to chromosome 12q bands 13.3-14.1, a breakpoint region implicated in a wide variety of solid tumors. To understand the genesis of three human Stat6 variant cDNAs, including a naturally occurring dominant negative species, we further characterized the genomic structure and flanking regions of the human Stat6 gene. The human Stat6 gene encompassed over 19 kb and contained 23 exons. For promoter studies, we introduced flanking sequence 5' of Stat6 exon 1 into a promoterless luciferase reporter vector and characterized basal promoter activity by deletion analysis. DNA sequence analysis revealed potential transcriptional regulation of the putative promoter through numerous consensus binding elements. Finally, we conclude that selective exon deletion and utilization of alternative donor/acceptor sites appear to explain best human Stat6 variant mRNAs.
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Affiliation(s)
- B K Patel
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, Building 37 Room 1E24, Bethesda, Maryland, 20892, USA
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29
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Abstract
Multiple biologic effects of interferon-α (IFN-α), including cell growth inhibition and antiviral protection, are initiated by tyrosine phosphorylation of STAT proteins. Although this signal pathway has been intensively investigated, the relevance of STAT signal persistence has received scant attention. Using paired isogenic lymphoma cells (Daudi), which either are sensitive or resistant to growth inhibition by IFN-α, we found comparable initial tyrosine phosphorylation of multiple STAT proteins; however, the phosphorylation durations and associated DNA-binding activities diverged. Phosphorylation and DNA-binding capacity of STAT1 decreased after 4 to 8 hours in resistant cells, as compared with 24 to 32 hours in sensitive cells, whereas phosphorylation of STAT3 and STAT5b was briefer in both lines. Functional significance of the prolonged STAT1 signal, therefore, was explored by experimental interruption of tyrosine phosphorylation, either by premature withdrawal of the IFN-α or deferred addition of pharmacologically diverse antagonists: staurosporine (protein kinase inhibitor), phorbol 12-myristate 13-acetate (growth promoter), or aurintricarboxylic acid (ligand competitor). Results indicated that an approximately 18-hour period of continued STAT1 phosphorylation was associated with growth arrest, but that antiviral protection developed earlier. These differences provide novel evidence of a temporal dimension to IFN-α signal specificity and show that duration of STAT1 activation may be a critical variable in malignant cell responsiveness to antiproliferative therapy.
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30
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Schaefer TS, Sanders LK, Park OK, Nathans D. Functional differences between Stat3alpha and Stat3beta. Mol Cell Biol 1997; 17:5307-16. [PMID: 9271408 PMCID: PMC232381 DOI: 10.1128/mcb.17.9.5307] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Stat3beta is a short form of Stat3 that differs from the longer form (Stat3alpha) by the replacement of the C-terminal 55 amino acid residues of Stat3alpha by 7 residues specific to Stat3beta. In COS cells transfected with Stat3 expression plasmids, both Stat3alpha and Stat3beta were activated for DNA binding and transcription by the same set of growth factors and cytokines and both, when activated, formed homodimers and heterodimers with Stat1. Only Stat3beta was active in the absence of added cytokine or growth factor. Activation of each form, including constitutive activation of Stat3beta, was correlated with the phosphorylation of tyrosine 705. Activated Stat3beta in transfected COS cells was more stable and had greater DNA-binding activity than activated Stat3alpha. However, relative to DNA-binding activity, Stat3alpha showed greater transcriptional activity than Stat3beta. A mutant of Stat3alpha lacking its highly acidic C-terminal 48 amino acids had properties indistinguishable from Stat3beta. We conclude that Stat3alpha and Stat3beta have significantly different properties due to the presence or absence of the acidic C-terminal tail of Stat3alpha rather than the C-terminal sequence peculiar to Stat3beta. In addition to its effect on transcription, we speculate that the acidic tail may destabilize the active dimeric form of Stat3alpha, resulting in lower DNA-binding activity of the Y705-phosphorylated form compared to Stat3beta and in more rapid dephosphorylation.
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Affiliation(s)
- T S Schaefer
- Howard Hughes Medical Institute and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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31
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Azam M, Lee C, Strehlow I, Schindler C. Functionally distinct isoforms of STAT5 are generated by protein processing. Immunity 1997; 6:691-701. [PMID: 9208842 DOI: 10.1016/s1074-7613(00)80445-8] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The interleukin-3 family of cytokines, which play an important role in the development of myeloid lineages, transduce signals through the JAK-STAT pathway. Previous studies demonstrate that this process entails the activation of four distinct isoforms of STAT5, where two shorter isoforms are activated in a distinct population of cells. We now demonstrate that the shorter isoforms represent carboxy-terminal truncations. Moreover, these truncations are not generated by RNA processing, but by a specific proteolytic activity. Consistent with the notion that truncated STAT5 isoforms transduce distinct signals, they fail to promote the activation of several known interleukin-3 target genes. These studies suggest that the activity of a specific protease may play a critical role in defining the biological responses transduced by STAT5.
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Affiliation(s)
- M Azam
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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32
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Kolla V, Weihua X, Kalvakolanu DV. Modulation of interferon action by retinoids. Induction of murine STAT1 gene expression by retinoic acid. J Biol Chem 1997; 272:9742-8. [PMID: 9092506 DOI: 10.1074/jbc.272.15.9742] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have previously demonstrated that up-regulation of STAT1 protein by all-trans-retinoic acid (RA) in interferon (IFN)-unresponsive cells permits growth inhibition by IFNs. Here, we show that the promoter of STAT1 directly responds to retinoic acid treatment. Sequence and functional analysis of the murine STAT1 promoter have identified a direct repeat motif that serves as a retinoic acid response element. Mutagenesis of this element resulted in a loss of response to RA. This element is activated by RA receptors alpha, beta, and gamma. In vivo, RA receptor beta and retinoid X receptor alpha preferentially interacted with this element. Thus, these data define a molecular basis for the synergy between IFNs and retinoids in tumor growth inhibition.
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Affiliation(s)
- V Kolla
- University of Maryland Cancer Center, Department of Microbiology & Immunology, Program in Oncology, Molecular and Cellular Biology Program, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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33
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Wang D, Stravopodis D, Teglund S, Kitazawa J, Ihle JN. Naturally occurring dominant negative variants of Stat5. Mol Cell Biol 1996; 16:6141-8. [PMID: 8887644 PMCID: PMC231617 DOI: 10.1128/mcb.16.11.6141] [Citation(s) in RCA: 216] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Stat5 was initially identified as a prolactin-induced member of the signal transducer and activator of transcription (Stat) family in sheep. However, Stat5 is also activated in the response to a variety of cytokines. In mice, and possibly in other species, there exist two Stat5 genes (Stat5a and Stat5b) that encode proteins of 92 and 94 kDa that are 95% identical. In the studies described here, we demonstrate that naturally occurring carboxyl-truncated, variant Stat5 proteins of 77 and 80 kDa exist and that these proteins are inducibly tyrosine phosphorylated in the response to several cytokines and form heterodimers with the full-length, wild-type proteins. Using expression constructs encoding truncated forms, we demonstrate that the truncated forms can be tyrosine phosphorylated and bind DNA. Surprisingly, the tyrosine phosphorylation of the carboxyl-truncated forms is considerably more stable than that of the wild-type proteins. Overexpression of a carboxyl-truncated Stat5a in cells resulted in the specific inhibition of the transcriptional activation by interleukin-3 of the genes for oncostatin M (Osm) and the cytokine-inducible, SH2 domain-containing gene (Cis), both of which have been shown to be normally regulated by Stat5. Although Stat5 dominantly suppressed the induction of these genes, no effects on cell proliferation were observed. Together, the results demonstrate the natural existence of potentially dominantly suppressive variants of Stat5 and implicate the carboxyl domain of Stats in transcriptional regulation and functions related to dephosphorylation.
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Affiliation(s)
- D Wang
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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34
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Vinkemeier U, Cohen SL, Moarefi I, Chait BT, Kuriyan J, Darnell JE. DNA binding of in vitro activated Stat1 alpha, Stat1 beta and truncated Stat1: interaction between NH2-terminal domains stabilizes binding of two dimers to tandem DNA sites. EMBO J 1996; 15:5616-26. [PMID: 8896455 PMCID: PMC452306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Stat1 alpha, Stat1 beta and a proteolytically defined truncated Stat1 (132-713, Stat1tc) have been prepared from recombinant sources. All three proteins were specifically phosphorylated on Tyr701 in vitro and the phosphoprotein purified to homogeneity. This was achieved by employing a new isolation scheme that does not include DNA affinity steps and readily allows for the isolation of tens of milligrams of activated Stat protein. The purified phosphoprotein was free of traces of unphosphorylated polypeptide as detected by mass spectrometry. The phosphorylated Stat1 preparations bound to various DNA recognition sites with the same Keq of approximately 1 x 10(-9) M; distinction between 'weak' and 'strong' binding sites is determined by the very rapid dissociation (< 30 s, t1/2) from 'weak' sites compared with 'strong' sites (approximately 3 min, t1/2). Reports of 'weak' tandem binding sites in a natural gene caused us to examine binding to tandem sites leading to the finding that the Stat1 alpha or beta (38 amino acids shorter on the C terminus) bound to two tandem sites (but not two head-to-head sites) with a higher stability than to a single recognition site. The N-terminally truncated protein Stat1tc did not show this cooperative binding, thus implicating the N-terminal domain in promoting Stat1-Stat1 dimer interaction.
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Affiliation(s)
- U Vinkemeier
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, NY 10021, USA
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35
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Bhattacharya S, Eckner R, Grossman S, Oldread E, Arany Z, D'Andrea A, Livingston DM. Cooperation of Stat2 and p300/CBP in signalling induced by interferon-alpha. Nature 1996; 383:344-7. [PMID: 8848048 DOI: 10.1038/383344a0] [Citation(s) in RCA: 425] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The transcription factor ISGF3 transduces interferon (IFN)-alpha signals and activates the transcription of cellular antiviral defence genes. Adenovirus E1A blocks the IFN-alpha response, allowing unhindered viral replication. ISGF3 consists of Stat1, Stat2 and p48. Here we show that p300 and/or CBP (CREB-binding protein), which are transcription adaptors targeted by E1A, interact specifically with Stat2. Binding occurs between the first cysteine-histidine-rich region of p300/CBP and the carboxy-terminal segment of Stat2, a domain essential for ISGF3 function. We find that this domain of Stat2 has transactivation potential, which correlates with its binding to p300/CBP. Moreover, E1A represses Stat2 transactivation and IFN-alpha-activated transcription by inhibiting p300/CBP function. This provides a new mechanism for inhibition of the IFN-alpha-activated antiviral response by E1A, and supports the view that E1A binding to p300/CBP has functional significance for adenovirus replication in its natural host.
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Affiliation(s)
- S Bhattacharya
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115, USA
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36
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Bromberg JF, Horvath CM, Wen Z, Schreiber RD, Darnell JE. Transcriptionally active Stat1 is required for the antiproliferative effects of both interferon alpha and interferon gamma. Proc Natl Acad Sci U S A 1996; 93:7673-8. [PMID: 8755534 PMCID: PMC38805 DOI: 10.1073/pnas.93.15.7673] [Citation(s) in RCA: 404] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Type I (alpha, beta) and type II (gamma) interferons (IFNs) can restrict the growth of many cell types. INF-stimulated gene transcription, a key early event in IFN response, acts through the Janus kinase-signal transducers and activators of transcription pathway, in which both IFN-alpha and IFN-gamma activate the transcription factor Stat1. A cell line lacking Stat1 (U3A) was not growth-arrested by IFN-alpha or IFN-gamma, and experiments were carried out with U3A cells permanently expressing normal or various mutant forms of Stat1 protein. Only cells in which complete Stat1 activity was available (Stat1alpha) were growth-inhibited by IFN-gamma. A mutant that supports 20-30% normal transcription did not cause growth restraint. In contrast, IFN-alpha growth restraint was imposed by cells producing Stat1beta, which lacks transcriptional activation potential. This parallels earlier results showing the truncated Stat1 can function in IFN-alpha gene activation. In addition to experiments on long-term cultured cells, we also found that wild-type primary mouse embryonic fibroblasts were inhibited by IFNs, but fibroblasts from Stat1-deficient mouse embryos were not inhibited by IFNs.
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Affiliation(s)
- J F Bromberg
- Laboratory of Molecular Cell Biology, The Rockefeller University, New York, NY 10021-6399, USA
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37
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Yan R, Luo H, Darnell JE, Dearolf CR. A JAK-STAT pathway regulates wing vein formation in Drosophila. Proc Natl Acad Sci U S A 1996; 93:5842-7. [PMID: 8650180 PMCID: PMC39149 DOI: 10.1073/pnas.93.12.5842] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We present evidence that the JAK-STAT signal transduction pathway regulates multiple developmental processes in Drosophila. We screened for second-site mutations that suppress the phenotype of the hyperactive hopTum-1 Jak kinase, and recovered a mutation that meiotically maps to the known chromosomal position of D-Stat, a Drosophila stat gene. This hypomorphic mutation, termed statHJ contains a nucleotide substitution in the first D-Stat intron, resulting in a reduction in the number of correctly processed transcripts. Further, the abnormally processed mRNA encodes a truncated protein that has a dominant negative effect on transcriptional activation by the wild-type cDNA in cell culture. statHJ mutants exhibit patterning defects that include the formation of ectopic wing veins, similar to those seen in mutants of the epidermal growth factor/receptor pathway. Abnormalities in embryonic and adult segmentation and in tracheal development were also observed. The hopTum-1 and statHJ mutations can partially compensate for each other genetically, and Hop overexpression can increase D-Stat transcriptional activity in vitro, indicating that the gene products interact in a common regulatory pathway.
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Affiliation(s)
- R Yan
- Laboratory of Molecular Cell Biology, The Rockerfeller University, New York, NY 10021, USA
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38
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Caldenhoven E, van Dijk TB, Solari R, Armstrong J, Raaijmakers JA, Lammers JW, Koenderman L, de Groot RP. STAT3beta, a splice variant of transcription factor STAT3, is a dominant negative regulator of transcription. J Biol Chem 1996; 271:13221-7. [PMID: 8675499 DOI: 10.1074/jbc.271.22.13221] [Citation(s) in RCA: 296] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The 89-kDa STAT3 protein is a latent transcription factor which is activated in response to cytokines (interleukin (IL)-5 and -6) and growth factors (epidermal growth factor). Binding of IL-5 to its specific receptor activates JAK2 which leads to the tyrosine phosphorylation of STAT3 proteins. Here we report the cloning of a cDNA encoding a variant of the transcription factor STAT3 (named STAT3beta) which was isolated by screening an eosinophil cDNA library. Compared to wild-type STAT3, STAT3beta lacks an internal domain of 50 base pairs located near the C terminus. This splice product is a naturally occurring isoform of STAT3 and encodes a 80-kDa protein. We found by reconstitution of the human IL-5R in COS cells that like STAT3, STAT3beta is phosphorylated on tyrosine and binds to the pIRE from the ICAM-1 promoter after IL-5 stimulation. However, STAT3beta fails to activate a pIRE containing promoter in transient transfection assays. Instead, co-expression of STAT3beta inhibits the transactivation potential of STAT3. These results suggests that STAT3beta functions as a negative regulator of transcription.
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Affiliation(s)
- E Caldenhoven
- Department of Pulmonary Diseases, University Hospital Utrecht, Utrecht, The Netherlands
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39
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Abstract
We identified alternatively spliced forms of Stat2 in human and mouse mRNAs. The spliced forms are generated by reading through the intron between exon 20 and 21, which correspond to the region encoding SH2 domain. The spliced forms contain a stop codon in SH2 domain, and therefore give rise to a short form of Stat2 when the mRNAs are translated. The putative translated proteins lack half of the SH2 domain, the tyrosine phosphorylation site required for dimerization (or oligomerization) and DNA binding, and C-terminal activation domain. The significance of these spliced forms is discussed.
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Affiliation(s)
- T Sugiyama
- Institute for Molecular and Cellular Biology, Osaka University, Japan
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40
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Yan R, Small S, Desplan C, Dearolf CR, Darnell JE. Identification of a Stat gene that functions in Drosophila development. Cell 1996; 84:421-30. [PMID: 8608596 DOI: 10.1016/s0092-8674(00)81287-8] [Citation(s) in RCA: 298] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A Drosophila Stat gene (D-Stat) with a zygotic segmental expression pattern was identified. This protein becomes phosphorylated on Tyr-704 when coexpressed in Schneider cells with a Drosophila janus kinase (JAK), Hopscotch (HOP). The phosphorylated protein binds specifically to the consensus sequence TTCCCGGAA. Suppressor mutations of hopTum-I, a dominant hyperactive allele of hop whose phenotype is hematocyte overproduction and tumor formation, were selected. One of these mutants, statHJ, mapped to the same chromosomal region (92E) as does D-Stat, had an incompletely penetrant pair rule phenotype, and exhibited aberrant expression of the pair rule gene even skipped (eve) at the cellular blastoderm stage. Two D-STAT-binding sites were identified within the eve stripe 3 enhancer region. Mutations in either of the STAT-binding sites greatly decreased the stripe 3 expression in transgenic flies. Clearly, the JAK-STAT pathway is connected to Drosophila early development.
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Affiliation(s)
- R Yan
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, New York 10021, USA
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41
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Meraz MA, White JM, Sheehan KC, Bach EA, Rodig SJ, Dighe AS, Kaplan DH, Riley JK, Greenlund AC, Campbell D, Carver-Moore K, DuBois RN, Clark R, Aguet M, Schreiber RD. Targeted disruption of the Stat1 gene in mice reveals unexpected physiologic specificity in the JAK-STAT signaling pathway. Cell 1996; 84:431-42. [PMID: 8608597 DOI: 10.1016/s0092-8674(00)81288-x] [Citation(s) in RCA: 1272] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The JAK-STAT signaling pathway has been implicated in mediating biological responses induced by many cytokines. However, cytokines that promote distinct cellular responses often activate identical STAT proteins, thereby raising the question of how specificity is manifest within this signaling pathway. Here we report the generation and characterization of mice deficient in STAT1. STAT1-deficient mice show no overt developmental abnormalities, but display a complete lack of responsiveness to either IFN alpha or IFN gamma and are highly sensitive to infection by microbial pathogens and viruses. In contrast, these mice respond normally to several other cytokines that activate STAT1 in vitro. These observations document that STAT1 plays an obligate and dedicated role in mediating IFN-dependent biologic responses and reveal an unexpected level of physiologic specificity for STAT1 action.
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Affiliation(s)
- M A Meraz
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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42
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Horvath CM, Darnell JE. The antiviral state induced by alpha interferon and gamma interferon requires transcriptionally active Stat1 protein. J Virol 1996; 70:647-50. [PMID: 8523587 PMCID: PMC189860 DOI: 10.1128/jvi.70.1.647-650.1996] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Both of the latent transcription factors activated by alpha interferon or gamma interferon contain the Stat1 protein. The role of Stat1 in virus interference mediated by interferons was directly examined by using cultured cells expressing Stat1 protein and its variants. In the absence of Stat1, no antiviral state is established. Full complementation of the antiviral state requires full-length Stat1 which is phosphorylated on both tyrosine 701 and serine 727. The closely related signal transducer and activator of transcription protein Stat3 cannot substitute for the antiviral properties of Stat1.
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Affiliation(s)
- C M Horvath
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, New York 10021, USA
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43
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Wen Z, Zhong Z, Darnell JE. Maximal activation of transcription by Stat1 and Stat3 requires both tyrosine and serine phosphorylation. Cell 1995; 82:241-50. [PMID: 7543024 DOI: 10.1016/0092-8674(95)90311-9] [Citation(s) in RCA: 1576] [Impact Index Per Article: 54.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Stat1 and Stat3 are latent transcriptional factors activated initially through phosphorylation on single tyrosine residues induced by cytokine and growth factor occupation of cell surface receptors. Here we show that phosphorylation on a single serine (residue 727) in each protein is also required for maximal transcriptional activity. Both cytokines and growth factors are capable of inducing the serine phosphorylation of Stat1 and Stat3. These experiments show that gene activation by Stat1 and Stat3, which obligatorily require tyrosine phosphorylation to become active, also depends for maximal activation on one or more of the many serine kinases.
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Affiliation(s)
- Z Wen
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, New York 10021-6399, USA
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