1
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Barrera-Lopez JF, Cumplido-Laso G, Olivera-Gomez M, Garrido-Jimenez S, Diaz-Chamorro S, Mateos-Quiros CM, Benitez DA, Centeno F, Mulero-Navarro S, Roman AC, Carvajal-Gonzalez JM. Early Atf4 activity drives airway club and goblet cell differentiation. Life Sci Alliance 2024; 7:e202302284. [PMID: 38176727 PMCID: PMC10766780 DOI: 10.26508/lsa.202302284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/06/2024] Open
Abstract
Activating transcription factor 4 (Atf4), which is modulated by the protein kinase RNA-like ER kinase (PERK), is a stress-induced transcription factor responsible for controlling the expression of a wide range of adaptive genes, enabling cells to withstand stressful conditions. However, the impact of the Atf4 signaling pathway on airway regeneration remains poorly understood. In this study, we used mouse airway epithelial cell culture models to investigate the role of PERK/Atf4 in respiratory tract differentiation. Through pharmacological inhibition and silencing of ATF4, we uncovered the crucial involvement of PERK/Atf4 in the differentiation of basal stem cells, leading to a reduction in the number of secretory cells. ChIP-seq analysis revealed direct binding of ATF4 to regulatory elements of genes associated with osteoblast differentiation and secretory cell function. Our findings provide valuable insights into the role of ATF4 in airway epithelial differentiation and its potential involvement in innate immune responses and cellular adaptation to stress.
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Affiliation(s)
- Juan F Barrera-Lopez
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Guadalupe Cumplido-Laso
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Marcos Olivera-Gomez
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Sergio Garrido-Jimenez
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Selene Diaz-Chamorro
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Clara M Mateos-Quiros
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Dixan A Benitez
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Francisco Centeno
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Sonia Mulero-Navarro
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Angel C Roman
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Jose M Carvajal-Gonzalez
- https://ror.org/0174shg90 Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
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2
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Mekbib KY, Muñoz W, Allington G, McGee S, Mehta NH, Shofi JP, Fortes C, Le HT, Nelson-Williams C, Nanda P, Dennis E, Kundishora AJ, Khanna A, Smith H, Ocken J, Greenberg ABW, Wu R, Moreno-De-Luca A, DeSpenza T, Zhao S, Marlier A, Jin SC, Alper SL, Butler WE, Kahle KT. Human genetics and molecular genomics of Chiari malformation type 1. Trends Mol Med 2023; 29:1059-1075. [PMID: 37802664 DOI: 10.1016/j.molmed.2023.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 10/08/2023]
Abstract
Chiari malformation type 1 (CM1) is the most common structural brain disorder involving the craniocervical junction, characterized by caudal displacement of the cerebellar tonsils below the foramen magnum into the spinal canal. Despite the heterogeneity of CM1, its poorly understood patho-etiology has led to a 'one-size-fits-all' surgical approach, with predictably high rates of morbidity and treatment failure. In this review we present multiplex CM1 families, associated Mendelian syndromes, and candidate genes from recent whole exome sequencing (WES) and other genetic studies that suggest a significant genetic contribution from inherited and de novo germline variants impacting transcription regulation, craniovertebral osteogenesis, and embryonic developmental signaling. We suggest that more extensive WES may identify clinically relevant, genetically defined CM1 subtypes distinguished by unique neuroradiographic and neurophysiological endophenotypes.
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Affiliation(s)
- Kedous Y Mekbib
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA; Harvard Center for Hydrocephalus and Neurodevelopmental Disorders, Massachusetts General Hospital, Boston, MA, USA
| | - William Muñoz
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA; Harvard Center for Hydrocephalus and Neurodevelopmental Disorders, Massachusetts General Hospital, Boston, MA, USA
| | - Garrett Allington
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Neel H Mehta
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - John P Shofi
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Carla Fortes
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Hao Thi Le
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | | | - Pranav Nanda
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Evan Dennis
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Adam J Kundishora
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Arjun Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Hannah Smith
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Jack Ocken
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Ana B W Greenberg
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Rui Wu
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Andres Moreno-De-Luca
- Department of Radiology, Autism and Developmental Medicine Institute, Genomic Medicine Institute, Geisinger, Danville, PA, USA
| | - Tyrone DeSpenza
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Shujuan Zhao
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA; Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Seth L Alper
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - William E Butler
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA; Harvard Center for Hydrocephalus and Neurodevelopmental Disorders, Massachusetts General Hospital, Boston, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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3
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Huang J, Ji X. Never a dull enzyme, RNA polymerase II. Transcription 2023; 14:49-67. [PMID: 37132022 PMCID: PMC10353340 DOI: 10.1080/21541264.2023.2208023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 05/04/2023] Open
Abstract
RNA polymerase II (Pol II) is composed of 12 subunits that collaborate to synthesize mRNA within the nucleus. Pol II is widely recognized as a passive holoenzyme, with the molecular functions of its subunits largely ignored. Recent studies employing auxin-inducible degron (AID) and multi-omics techniques have revealed that the functional diversity of Pol II is achieved through the differential contributions of its subunits to various transcriptional and post-transcriptional processes. By regulating these processes in a coordinated manner through its subunits, Pol II can optimize its activity for diverse biological functions. Here, we review recent progress in understanding Pol II subunits and their dysregulation in diseases, Pol II heterogeneity, Pol II clusters and the regulatory roles of RNA polymerases.
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Affiliation(s)
- Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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4
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Li Y, Huang J, Bao L, Zhu J, Duan W, Zheng H, Wang H, Jiang Y, Liu W, Zhang M, Yu Y, Yi C, Ji X. RNA Pol II preferentially regulates ribosomal protein expression by trapping disassociated subunits. Mol Cell 2023; 83:1280-1297.e11. [PMID: 36924766 DOI: 10.1016/j.molcel.2023.02.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/12/2022] [Accepted: 02/23/2023] [Indexed: 03/17/2023]
Abstract
RNA polymerase II (RNA Pol II) has been recognized as a passively regulated multi-subunit holoenzyme. However, the extent to which RNA Pol II subunits might be important beyond the RNA Pol II complex remains unclear. Here, fractions containing disassociated RPB3 (dRPB3) were identified by size exclusion chromatography in various cells. Through a unique strategy, i.e., "specific degradation of disassociated subunits (SDDS)," we demonstrated that dRPB3 functions as a regulatory component of RNA Pol II to enable the preferential control of 3' end processing of ribosomal protein genes directly through its N-terminal domain. Machine learning analysis of large-scale genomic features revealed that the little elongation complex (LEC) helps to specialize the functions of dRPB3. Mechanistically, dRPB3 facilitates CBC-PCF11 axis activity to increase the efficiency of 3' end processing. Furthermore, RPB3 is dynamically regulated during development and diseases. These findings suggest that RNA Pol II gains specific regulatory functions by trapping disassociated subunits in mammalian cells.
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Affiliation(s)
- Yuanjun Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Lijun Bao
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Junyi Zhu
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Wenjia Duan
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Haonan Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Hui Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yongpeng Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Weiwei Liu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Meiling Zhang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yang Yu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
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5
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Hu P, Wang B, Chen T, Xu Y, Zheng G, Zhu Y, Du X. RNA polymerase II subunit 3 regulates vesicular, overexpressed in cancer, prosurvival protein 1 expression to promote hepatocellular carcinoma. J Int Med Res 2021; 49:300060521990512. [PMID: 33845647 PMCID: PMC8047087 DOI: 10.1177/0300060521990512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/05/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To explore the relationships between hepatocellular carcinoma (HCC) and the expression of RNA polymerase II subunit 3 (RPB3) and vesicular, overexpressed in cancer, prosurvival protein 1 (VOPP1), and to determine whether RPB3 regulates VOPP1 expression to promote HCC cell proliferation, tumor growth, and tumorigenesis. METHODS HCC and adjacent liver samples were collected from 51 patients with HCC who underwent surgical excision between September 20, 2010 and June 22, 2017. Immunohistochemical staining, western blot, quantitative PCR, plate colony assay, and RNA microarray were used to detect relevant indexes for further analyses. RESULTS VOPP1 was shown to function as a target gene of RPB3 in facilitating HCC proliferation, and was downregulated after RBP3 silencing. Additionally, hepatic tumor tissues demonstrated high VOPP1 expression. Furthermore, VOPP1 silencing suppressed tumor growth and cell proliferation and elicited apoptosis. CONCLUSION RPB3 regulates VOPP1 expression to promote HCC cell proliferation, tumor growth, and tumorigenesis.
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Affiliation(s)
- Peng Hu
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai, Zhejiang, China
| | - Binfeng Wang
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai, Zhejiang, China
| | - Ting Chen
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai, Zhejiang, China
| | - Yongfu Xu
- Department of Hepatobiliary Surgery, Enze Hospital,Wenzhou Medical University, Taizhou, Zhejiang, China
| | - Guoqun Zheng
- Department of Hepatobiliary Surgery, Enze Hospital,Wenzhou Medical University, Taizhou, Zhejiang, China
| | - Yu Zhu
- Department of Hepatobiliary Surgery, Enze Hospital,Wenzhou Medical University, Taizhou, Zhejiang, China
| | - Xuefeng Du
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai, Zhejiang, China
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6
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Proshkin SA, Shematorova EK, Shpakovski GV. The Human Isoform of RNA Polymerase II Subunit hRPB11bα Specifically Interacts with Transcription Factor ATF4. Int J Mol Sci 2019; 21:E135. [PMID: 31878192 PMCID: PMC6981380 DOI: 10.3390/ijms21010135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/17/2019] [Accepted: 12/22/2019] [Indexed: 11/27/2022] Open
Abstract
Rpb11 subunit of RNA polymerase II of Eukaryotes is related to N-terminal domain of eubacterial α subunit and forms a complex with Rpb3 subunit analogous to prokaryotic α2 homodimer, which is involved in RNA polymerase assembly and promoter recognition. In humans, a POLR2J gene family has been identified that potentially encodes several hRPB11 proteins differing mainly in their short C-terminal regions. The functions of the different human specific isoforms are still mainly unknown. To further characterize the minor human specific isoform of RNA polymerase II subunit hRPB11bα, the only one from hRPB11 (POLR2J) homologues that can replace its yeast counterpart in vivo, we used it as bait in a yeast two-hybrid screening of a human fetal brain cDNA library. By this analysis and subsequent co-purification assay in vitro, we identified transcription factor ATF4 as a prominent partner of the minor RNA polymerase II (RNAP II) subunit hRPB11bα. We demonstrated that the hRPB11bα interacts with leucine b-Zip domain located on the C-terminal part of ATF4. Overexpression of ATF4 activated the reporter more than 10-fold whereas co-transfection of hRPB11bα resulted in a 2.5-fold enhancement of ATF4 activation. Our data indicate that the mode of interaction of human RNAP II main (containing major for of hRPB11 subunit) and minor (containing hRPB11bα isoform of POLR2J subunit) transcription enzymes with ATF4 is certainly different in the two complexes involving hRPB3-ATF4 (not hRPB11a-ATF4) and hRpb11bα-ATF4 platforms in the first and the second case, respectively. The interaction of hRPB11bα and ATF4 appears to be necessary for the activation of RNA polymerase II containing the minor isoform of the hRPB11 subunit (POLR2J) on gene promoters regulated by this transcription factor. ATF4 activates transcription by directly contacting RNA polymerase II in the region of the heterodimer of α-like subunits (Rpb3-Rpb11) without involving a Mediator, which provides fast and highly effective activation of transcription of the desired genes. In RNA polymerase II of Homo sapiens that contains plural isoforms of the subunit hRPB11 (POLR2J), the strength of the hRPB11-ATF4 interaction appeared to be isoform-specific, providing the first functional distinction between the previously discovered human forms of the Rpb11 subunit.
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Affiliation(s)
- Sergey A. Proshkin
- Laboratory of Mechanisms of Gene Expression, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.P.); (E.K.S.)
- Engelhardt Institute of Molecular Biology, Center for Precision Genome Editing and Genetic Technologies for Biomedicine, 119991 Moscow, Russia
| | - Elena K. Shematorova
- Laboratory of Mechanisms of Gene Expression, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.P.); (E.K.S.)
| | - George V. Shpakovski
- Laboratory of Mechanisms of Gene Expression, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.P.); (E.K.S.)
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7
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Multisubunit DNA-Dependent RNA Polymerases from Vaccinia Virus and Other Nucleocytoplasmic Large-DNA Viruses: Impressions from the Age of Structure. Microbiol Mol Biol Rev 2017; 81:81/3/e00010-17. [PMID: 28701329 DOI: 10.1128/mmbr.00010-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The past 17 years have been marked by a revolution in our understanding of cellular multisubunit DNA-dependent RNA polymerases (MSDDRPs) at the structural level. A parallel development over the past 15 years has been the emerging story of the giant viruses, which encode MSDDRPs. Here we link the two in an attempt to understand the specialization of multisubunit RNA polymerases in the domain of life encompassing the large nucleocytoplasmic DNA viruses (NCLDV), a superclade that includes the giant viruses and the biochemically well-characterized poxvirus vaccinia virus. The first half of this review surveys the recently determined structural biology of cellular RNA polymerases for a microbiology readership. The second half discusses a reannotation of MSDDRP subunits from NCLDV families and the apparent specialization of these enzymes by virus family and by subunit with regard to subunit or domain loss, subunit dissociability, endogenous control of polymerase arrest, and the elimination/customization of regulatory interactions that would confer higher-order cellular control. Some themes are apparent in linking subunit function to structure in the viral world: as with cellular RNA polymerases I and III and unlike cellular RNA polymerase II, the viral enzymes seem to opt for speed and processivity and seem to have eliminated domains associated with higher-order regulation. The adoption/loss of viral RNA polymerase proofreading functions may have played a part in matching intrinsic mutability to genome size.
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8
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Pakos-Zebrucka K, Koryga I, Mnich K, Ljujic M, Samali A, Gorman AM. The integrated stress response. EMBO Rep 2016; 17:1374-1395. [PMID: 27629041 DOI: 10.15252/embr.201642195] [Citation(s) in RCA: 1499] [Impact Index Per Article: 187.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 08/23/2016] [Indexed: 02/06/2023] Open
Abstract
In response to diverse stress stimuli, eukaryotic cells activate a common adaptive pathway, termed the integrated stress response (ISR), to restore cellular homeostasis. The core event in this pathway is the phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α) by one of four members of the eIF2α kinase family, which leads to a decrease in global protein synthesis and the induction of selected genes, including the transcription factor ATF4, that together promote cellular recovery. The gene expression program activated by the ISR optimizes the cellular response to stress and is dependent on the cellular context, as well as on the nature and intensity of the stress stimuli. Although the ISR is primarily a pro-survival, homeostatic program, exposure to severe stress can drive signaling toward cell death. Here, we review current understanding of the ISR signaling and how it regulates cell fate under diverse types of stress.
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Affiliation(s)
- Karolina Pakos-Zebrucka
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Izabela Koryga
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Katarzyna Mnich
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Mila Ljujic
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Adrienne M Gorman
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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Chen L, Guan L, Qian P, Xu F, Wu Z, Wu Y, He K, Gou X, Li J, Hou S. NRPB3, the third largest subunit of RNA polymerase II, is essential for stomatal patterning and differentiation in Arabidopsis. Development 2016; 143:1600-11. [PMID: 26989174 PMCID: PMC4909857 DOI: 10.1242/dev.129098] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 03/03/2016] [Indexed: 12/22/2022]
Abstract
Stomata are highly specialized epidermal structures that control transpiration and gas exchange between plants and the environment. Signal networks underlying stomatal development have been previously uncovered but much less is known about how signals involved in stomatal development are transmitted to RNA polymerase II (Pol II or RPB), which plays a central role in the transcription of mRNA coding genes. Here, we identify a partial loss-of-function mutation of the third largest subunit of nuclear DNA-dependent Pol II (NRPB3) that exhibits an increased number of stomatal lineage cells and paired stomata. Phenotypic and genetic analyses indicated that NRPB3 is not only required for correct stomatal patterning, but is also essential for stomatal differentiation. Protein-protein interaction assays showed that NRPB3 directly interacts with two basic helix-loop-helix (bHLH) transcription factors, FAMA and INDUCER OF CBF EXPRESSION1 (ICE1), indicating that NRPB3 serves as an acceptor for signals from transcription factors involved in stomatal development. Our findings highlight the surprisingly conserved activating mechanisms mediated by the third largest subunit of Pol II in eukaryotes. Summary: RNA polymerase II subunit NRPB3 interacts with stomatal bHLH transcription factors FAMA and ICE1, connecting the stomatal development pathway to the general transcription machinery.
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Affiliation(s)
- Liang Chen
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Liping Guan
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Pingping Qian
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Fan Xu
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Zhongliang Wu
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Yujun Wu
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Kai He
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Xiaoping Gou
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Jia Li
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Suiwen Hou
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
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10
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Fang ZP, Jiang BG, Zhang FB, Wang AD, Ji YM, Xu YF, Li JC, Zhou WP, Zhou WJ, Han HX. Rpb3 promotes hepatocellular carcinoma through its N-terminus. Oncotarget 2015; 5:9256-68. [PMID: 25211001 PMCID: PMC4253432 DOI: 10.18632/oncotarget.2389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The expression of RNA polymerase II subunit 3 (Rpb3) was found frequent up-regulation in Hepatocellular carcinoma (HCC) tumors. Significant associations could also be drawn between increased expressions of Rpb3 and advance HCC staging and shorter disease-free survival of patients. Overexpression of Rpb3 increased HCC cell proliferation, migratory rate and tumor growth in nude mice, whereas suppression of Rpb3 using shRNA inhibited these effects. For mechanism study, we found that Rpb3 bound directly to Snail, downregulated E-cadherin, induced HCC cells epithelial-mesenchymal transition (EMT). In particular, N-terminus of Rpb3 blocked Rpb3 binding to Snail, inhibited Rpb3-high-expression HCC cells proliferation, migration, tumor growth in nude mice, and also inhibited DEN-induced liver tumorigenesis. Furthermore, N-terminus of Rpb3 did not inhibit normal liver cells or Rpb3-low-expression HCC cells proliferation. These findings suggest that N-terminus of Rpb3 selectively inhibits Rpb3-high-expression HCC cells proliferation. N-terminus of Rpb3 may be useful in treating patients diagnosed with Rpb3-high-expression HCC.
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Affiliation(s)
- Zhe-Ping Fang
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
| | - Bei-Ge Jiang
- Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Fa-Biao Zhang
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
| | - Ai-Dong Wang
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
| | - Yi-Ming Ji
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
| | - Yong-Fu Xu
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
| | - Ji-Cheng Li
- Institute of Cell Biology, Zhejiang University, 866 Yu-Hang-Tang Road, Hangzhou 310058, China
| | - Wei-Ping Zhou
- Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Wei-Jie Zhou
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA
| | - Hai-Xiong Han
- Department of Hepatobiliary Surgery, Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, China
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11
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Leone V, Langella C, Esposito F, Arra C, Palma G, Rea D, Paciello O, Merolla F, De Biase D, Papparella S, Celetti A, Fusco A. Ccdc6 knock-in mice develop thyroid hyperplasia associated to an enhanced CREB1 activity. Oncotarget 2015; 6:15628-38. [PMID: 25970781 PMCID: PMC4558175 DOI: 10.18632/oncotarget.3858] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/14/2015] [Indexed: 02/06/2023] Open
Abstract
CCDC6 was originally identified upon rearrangement with RET in human thyroid papillary carcinomas generating the RET/PTC1 oncogene. We have previously reported that CCDC6 interacts with CREB1 and represses its transcriptional activity. Since the function of at least one allele of CCDC6 is lost following RET/PTC1 rearrangements, we aimed at the generation of mice, carrying a CCDC6 mutant gene. Previous studies suggested that the coiled-coil domain of CCDC6, mainly encoded by human exon 2, is required for the protein function. Therefore, we engineered a murine Ccdc6 construct, carrying a deletion of the exon 2, that was able to exert only a mild repression on CREB1 transcriptional activity, with respect to the wild type Ccdc6. Subsequently, we generated Ccdc6-ex2 knock-in mice. These mice developed thyroid hyperplasia associated with an enhanced CREB1 activity and an increased expression of the CREB-1 regulated genes. These results strongly support a CCDC6 promoting role, ascribed to its functional impairment, in the development of thyroid papillary carcinomas harboring the RET/PTC1 oncogene.
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Affiliation(s)
- Vincenza Leone
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Concetta Langella
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Francesco Esposito
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Claudio Arra
- Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, Italy
| | - Giuseppe Palma
- Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, Italy
| | - Domenica Rea
- Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione Giovanni Pascale", IRCCS, Naples, Italy
| | - Orlando Paciello
- Department of Pathology and Animal Health, University of Naples "Federico II", Naples, Italy
| | - Francesco Merolla
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Davide De Biase
- Department of Pathology and Animal Health, University of Naples "Federico II", Naples, Italy
| | - Serenella Papparella
- Department of Pathology and Animal Health, University of Naples "Federico II", Naples, Italy
| | - Angela Celetti
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Alfredo Fusco
- Istituto per l'Endocrinologia ed Oncologia Sperimentale del CNR e/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Naples, Italy
- Instituto Nacional de Câncer - INCA, Rua André Cavalcanti, Rio de Janeiro, CEP RJ, Brazil
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12
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Functional characterization of the mouse melanocortin 3 receptor gene promoter. Gene 2015; 562:62-9. [PMID: 25701401 DOI: 10.1016/j.gene.2015.02.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 02/09/2015] [Accepted: 02/15/2015] [Indexed: 11/22/2022]
Abstract
Melanocortin receptor 3 (MC3R) is expressed in the hypothalamus and pituitary in humans and rodents, and is involved in the control of feeding, energy metabolism, and pituitary function. In the mouse pituitary, MC3R is detected in mammotrophs. This study aimed to clarify the regulatory mechanism for Mc3r expression in the mouse pituitary. The promoter activities of reporter constructs for the MC3R gene 5'-flanking region up to -4000 bp (transcription initiation site designated as +1) were analyzed. The promoter activity significantly increased in the -86/+109 construct, but decreased in the -38/+109 construct, indicating that the minimal promoter required for basal expression of Mc3r is located in the -86/+109 region. Putative binding sites for transcription factors AP-1 and ATF4 were found in the 5'-flanking region of Mc3r. Site-directed mutation or deletion of these sites affected the promoter activities. In gel-shift assays with a nuclear extract of mouse anterior pituitary cells, band-shifts were detected for both sites after the addition of the nuclear extract, and were decreased in the presence of excess unlabeled probe competitors. These results indicated that both sites were involved in the regulation of Mc3r expression in anterior pituitary cells. Estradiol-17β treatment increased the Mc3r promoter activity, indicating that the gene is regulated by estradiol-17β. In conclusion, we have demonstrated the minimum promoter region required for Mc3r expression, and identified two binding sites for AP-1 and ATF4 and in the 5' upstream-flanking region of Mc3r that are essential for Mc3r expression.
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13
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Luise C, Merolla F, Leone V, Paladino S, Sarnataro D, Fusco A, Celetti A. Identification of sumoylation sites in CCDC6, the first identified RET partner gene in papillary thyroid carcinoma, uncovers a mode of regulating CCDC6 function on CREB1 transcriptional activity. PLoS One 2012; 7:e49298. [PMID: 23145146 PMCID: PMC3492267 DOI: 10.1371/journal.pone.0049298] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 10/08/2012] [Indexed: 11/23/2022] Open
Abstract
CCDC6 was originally identified in chimeric genes as caused by chromosomal translocation involving the RET protooncogene in some thyroid tumors. Recognised as a 65 kDa pro-apoptotic phosphoprotein, CCDC6 has been enrolled as an ATM substrate that contribute to protect genome integrity by modulating PP4c activity in response to genotoxic stress. Recently, CCDC6 has been identified as a repressor of CREB1-dependent transcription. Sumoylation has emerged as an important mechanism in transcriptional control. Here, we report the identification and characterization of three sites of sumoylation in CCDC6 (K74, K266 and K424) which are highly conserved in vertebrates. We demonstrate that the post-translational modifications by SUMO2 constrain most of the CCDC6 protein in the cytosol and affect its functional interaction with CREB1 with a decrease of CCDC6 repressive function on CREB1 transcriptional activity. Indeed, the impairment of functional outcome of sumoylated CCDC6 is obtained knocking down all three the sumoylation sites. Interestingly, in thyroid cells the SUMO2-mediated CCDC6 post-translational modifications are induced by Forskolin, a cAMP analog. Signal transduction via the cAMP pathway is known to be ubiquitous and represents a major line of communication between many organisms and their environment. We believe that CCDC6 could be an important player in the dynamics of cAMP signaling by fine regulating CREB1 transcriptional activity in normal and transformed thyroid cells.
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Affiliation(s)
- Chiara Luise
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, Università Federico II, Naples, Italy
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università Federico II, Naples, Italy
| | - Francesco Merolla
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, Università Federico II, Naples, Italy
| | - Vincenza Leone
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, Università Federico II, Naples, Italy
| | - Simona Paladino
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università Federico II, Naples, Italy
- CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Daniela Sarnataro
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università Federico II, Naples, Italy
- CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Alfredo Fusco
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, Università Federico II, Naples, Italy
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università Federico II, Naples, Italy
| | - Angela Celetti
- Istituto di Endocrinologia ed Oncologia Sperimentale, CNR, Università Federico II, Naples, Italy
- * E-mail:
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14
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Gene expression profile in bone of diabetes-prone BB/OK rats fed a high-fat diet. GENES AND NUTRITION 2012; 8:99-104. [PMID: 22639302 DOI: 10.1007/s12263-012-0299-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 05/02/2012] [Indexed: 12/13/2022]
Abstract
A high-fat diet (HFD) has been recognized as a risk factor for diseases such as dyslipidemia, atherosclerosis, obesity, and osteoporosis. However, studies analyzing gene expression after HFD in bone are rare. That prompted us to analyze the expression of selected genes in bone of 4-week-old diabetes-prone B(io)B(reeding) rats. Two breeding pairs were fed a HFD (+10 % tallow) or were fed a normal diet (ND; Ssniff R-Z) before mating and afterward during pregnancy. After the birth of progeny, parents continued to be given HFD or ND until the progeny was weaned (3 weeks). Thereafter, offspring were weaned and were fed the same food as their parents up to an age of 4 weeks. Body weight was measured at an age of 4 weeks, and subsequently 13 HFD rats and 13 ND rats were killed and the tibial bone was harvested to analyze the expression of 53 genes in bone. All rats fed HFD were significantly heavier than rats fed ND after 3 and 4 weeks. The diet also influenced the expression of genes in bone. There were significant differences in 20 out of 53 genes studied between rats fed HFD compared with rats fed ND. Four out of 20 had a lower and 17 out of 20 genes a higher expression in HFD rats, but differences in gene expression showed obvious differences between males and females. There were only two genes that were similarly different between males and females: Bmp4 and Atf4. Two genes, Foxg1 and Npy, were inversely expressed in males and females. It seems that the gene expression is differently regulated by diet during pregnancy and later in life between males and females. Nevertheless, it cannot be excluded that HFD also acts as an epigenetic factor in the development of offspring in utero.
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15
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Lessner FH, Jennings ME, Hirata A, Duin EC, Lessner DJ. Subunit D of RNA polymerase from Methanosarcina acetivorans contains two oxygen-labile [4Fe-4S] clusters: implications for oxidant-dependent regulation of transcription. J Biol Chem 2012; 287:18510-23. [PMID: 22457356 DOI: 10.1074/jbc.m111.331199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Subunit D of multisubunit RNA polymerase from many species of archaea is predicted to bind one to two iron-sulfur (Fe-S) clusters, the function of which is unknown. A survey of encoded subunit D in the genomes of sequenced archaea revealed six distinct groups based on the number of complete or partial [4Fe-4S] cluster motifs within domain 3. Only subunit D from strictly anaerobic archaea, including all members of the Methanosarcinales, are predicted to bind two [4Fe-4S] clusters. We report herein the purification and characterization of Methanosarcina acetivorans subunit D in complex with subunit L. Expression of subunit D and subunit L in Escherichia coli resulted in the purification of a D-L heterodimer with only partial [4Fe-4S] cluster content. Reconstitution in vitro with iron and sulfide revealed that the M. acetivorans D-L heterodimer is capable of binding two redox-active [4Fe-4S] clusters. M. acetivorans subunit D deleted of domain 3 (DΔD3) was still capable of co-purifying with subunit L but was devoid of [4Fe-4S] clusters. Affinity purification of subunit D or subunit DΔD3 from M. acetivorans resulted in the co-purification of endogenous subunit L with each tagged subunit D. Overall, these results suggest that domain 3 of subunit D is required for [4Fe-4S] cluster binding, but the [4Fe-4S] clusters and domain 3 are not required for the formation of the D-L heterodimer. However, exposure of two [4Fe-4S] cluster-containing D-L heterodimer to oxygen resulted in loss of the [4Fe-4S] clusters and subsequent protein aggregation, indicating that the [4Fe-4S] clusters influence the stability of the D-L heterodimer and therefore have the potential to regulate the assembly and/or activity of RNA polymerase in an oxidant-dependent manner.
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Affiliation(s)
- Faith H Lessner
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, USA
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16
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Wang C, Guo F. Effects of activating transcription factor 4 deficiency on carbohydrate and lipid metabolism in mammals. IUBMB Life 2012; 64:226-30. [PMID: 22223547 DOI: 10.1002/iub.605] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 11/23/2011] [Indexed: 01/13/2023]
Abstract
It has been shown that the mammalian activating transcription factor 4 (ATF4) is involved in many different physiological events, such as eye development, stress response, learning, and memory. However, several recent studies have demonstrated that ATF4 also plays an important role in the regulation of lipid and glucose metabolism, energy homeostasis, insulin secretion, and sensitivity, suggesting that ATF4 is a master regulator of metabolism. This review summarizes the most recent progress in the understanding of the novel roles of ATF4 in the regulation of metabolism.
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Affiliation(s)
- Chunxia Wang
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, The Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, China
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17
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Corbi N, Batassa EM, Pisani C, Onori A, Di Certo MG, Strimpakos G, Fanciulli M, Mattei E, Passananti C. The eEF1γ subunit contacts RNA polymerase II and binds vimentin promoter region. PLoS One 2010; 5:e14481. [PMID: 21217813 PMCID: PMC3013090 DOI: 10.1371/journal.pone.0014481] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 12/05/2010] [Indexed: 02/06/2023] Open
Abstract
Here, we show that the eukaryotic translation elongation factor 1 gamma (eEF1γ) physically interacts with the RNA polymerase II (pol II) core subunit 3 (RPB3), both in isolation and in the context of the holo-enzyme. Importantly, eEF1γ has been recently shown to bind Vimentin mRNA. By chromatin immunoprecipitation experiments, we demonstrate, for the first time, that eEF1γ is also physically present on the genomic locus corresponding to the promoter region of human Vimentin gene. The eEF1γ depletion causes the Vimentin protein to be incorrectly compartmentalised and to severely compromise cellular shape and mitochondria localisation. We demonstrate that eEF1γ partially colocalises with the mitochondrial marker Tom20 and that eEF1γ depletion increases mitochondrial superoxide generation as well as the total levels of carbonylated proteins. Finally, we hypothesise that eEF1γ, in addition to its role in translation elongation complex, is involved in regulating Vimentin gene by contacting both pol II and the Vimentin promoter region and then shuttling/nursing the Vimentin mRNA from its gene locus to its appropriate cellular compartment for translation.
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Affiliation(s)
- Nicoletta Corbi
- Istituto di Biologia e Patologia Molecolari CNR, c/o Regina Elena Cancer Institute, Rome, Italy
| | - Enrico Maria Batassa
- Istituto di Biologia e Patologia Molecolari CNR, c/o Regina Elena Cancer Institute, Rome, Italy
| | - Cinzia Pisani
- Istituto di Biologia e Patologia Molecolari CNR, c/o Regina Elena Cancer Institute, Rome, Italy
- Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy
| | - Annalisa Onori
- Istituto di Biologia e Patologia Molecolari CNR, c/o Regina Elena Cancer Institute, Rome, Italy
| | - Maria Grazia Di Certo
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche (CNR), IRCCS Fondazione S. Lucia, Rome, Italy
| | - Georgios Strimpakos
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche (CNR), IRCCS Fondazione S. Lucia, Rome, Italy
| | - Maurizio Fanciulli
- Department of Therapeutic Programs Development, Regina Elena Cancer Institute, Rome, Italy
| | - Elisabetta Mattei
- Istituto di Neurobiologia e Medicina Molecolare, Consiglio Nazionale delle Ricerche (CNR), IRCCS Fondazione S. Lucia, Rome, Italy
| | - Claudio Passananti
- Istituto di Biologia e Patologia Molecolari CNR, c/o Regina Elena Cancer Institute, Rome, Italy
- * E-mail:
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18
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Liang Q, Deng H, Sun CW, Townes TM, Zhu F. Negative regulation of IRF7 activation by activating transcription factor 4 suggests a cross-regulation between the IFN responses and the cellular integrated stress responses. THE JOURNAL OF IMMUNOLOGY 2010; 186:1001-10. [PMID: 21148039 DOI: 10.4049/jimmunol.1002240] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cells react to viral infection by exhibiting IFN-based innate immune responses and integrated stress responses, but little is known about the interrelationships between the two. In this study, we report a linkage between these two host-protective cellular mechanisms. We found that IFN regulatory factor (IRF)7, the master regulator of type I IFN gene expression, interacts with activating transcription factor (ATF)4, a key component of the integrated stress responses whose translation is induced by viral infection and various stresses. We have demonstrated that IRF7 upregulates ATF4 activity and expression, whereas ATF4 in return inhibits IRF7 activation, suggesting a cross-regulation between the IFN response and the cellular integrated stress response that controls host innate immune defense against viral infection.
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Affiliation(s)
- Qiming Liang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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19
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CCDC6 represses CREB1 activity by recruiting histone deacetylase 1 and protein phosphatase 1. Oncogene 2010; 29:4341-51. [PMID: 20498639 DOI: 10.1038/onc.2010.179] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
RET/papillary thyroid carcinoma 1 (PTC1) oncogene is frequently activated in human PTCs. It is characterized by the fusion of the intracellular kinase-encoding domain of RET to the first 101 amino acids of CCDC6. The aim of our work is to characterize the function of the CCDC6 protein to better understand the function of its truncation, that results in the loss of the expression of one allele, in the process of thyroid carcinogenesis. Here, we report that CCDC6 interacts with CREB1 and represses its transcriptional activity by recruiting histone deacetylase 1 and protein phosphatase 1 proteins at the CRE site of the CREB1 target genes. Finally, we show an increased CREB1 phosphorylation and activity in PTCs carrying the RET/PTC1 oncogene. Consistently, an increased expression of two known CREB1 target genes, AREG and cyclin A, was observed in this subgroup of thyroid papillary carcinomas. Therefore, the repression of CREB1 activity by CCDC6 has a critical function in the development of human thyroid papillary carcinomas carrying RET/PTC1 activation.
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20
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Suomela S, Elomaa O, Skoog T, Ala-aho R, Jeskanen L, Pärssinen J, Latonen L, Grénman R, Kere J, Kähäri VM, Saarialho-Kere U. CCHCR1 is up-regulated in skin cancer and associated with EGFR expression. PLoS One 2009; 4:e6030. [PMID: 19551138 PMCID: PMC2696036 DOI: 10.1371/journal.pone.0006030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 05/21/2009] [Indexed: 01/21/2023] Open
Abstract
Despite chronic inflammation, psoriatic lesions hardly ever progress to skin cancer. Aberrant function of the CCHCR1 gene (Coiled-Coil α-Helical Rod protein 1, HCR) within the PSORS1 locus may contribute to the onset of psoriasis. As CCHCR1 is expressed in certain cancers and regulates keratinocyte (KC) proliferation in a transgenic mouse model, we studied its relation to proliferation in cutaneous squamous cell cancer (SCC) cell lines by expression arrays and quantitative RT-PCR and in skin tumors by immunohistochemistry. CCHCR1 protein was detected in the pushing border of SCC and lining basal cell carcinoma islands. Different from psoriasis, Ki67 had a similar expression pattern as CCHCR1. The most intense CCHCR1 staining occurred in areas positive for epidermal growth factor receptor (EGFR). Expression of CCHCR1 mRNA was upregulated 30–80% in SCC lines when compared to normal KCs and correlated positively with Ki67 expression. The most aggressive and invasive tumor cell lines (RT3, FaDu) expressed CCHCR1 mRNA less than non-tumorigenic HaCaT cells. Moreover, the tumor promoters okadaic acid and menadione downregulated CCHCR1 mRNA. We conclude that both in psoriasis and the early stages of KC transformation, CCHCR1 may function as a negative regulator of proliferation, but beyond a certain point in oncogenesis cannot control this phenomenon any longer.
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Affiliation(s)
- Sari Suomela
- Department of Dermatology, Helsinki University Central Hospital and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Outi Elomaa
- Department of Medical Genetics, University of Helsinki, and Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Tiina Skoog
- Department of Biosciences and Nutrition at Novum, Karolinska Institutet, Huddinge, Sweden
- Departments of Clinical Science and Education and Section of Dermatology, Karolinska Institutet at Stockholm Söder Hospital, Stockholm, Sweden
| | - Risto Ala-aho
- Department of Dermatology, University of Turku, Turku University Central Hospital, Turku, Finland
- Medicity Research Laboratory, University of Turku, Turku, Finland
| | - Leila Jeskanen
- Department of Pathology, Helsinki University Central Hospital and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Jenita Pärssinen
- Department of Dermatology, Helsinki University Central Hospital and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Leena Latonen
- Molecular Cancer Biology Program and Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Reidar Grénman
- Department of Otorhinolaryngology-Head and Neck Surgery, Turku University Central Hospital, Turku, Finland
| | - Juha Kere
- Department of Medical Genetics, University of Helsinki, and Folkhälsan Institute of Genetics, Helsinki, Finland
- Department of Biosciences and Nutrition at Novum, Karolinska Institutet, Huddinge, Sweden
| | - Veli-Matti Kähäri
- Department of Dermatology, University of Turku, Turku University Central Hospital, Turku, Finland
- Medicity Research Laboratory, University of Turku, Turku, Finland
| | - Ulpu Saarialho-Kere
- Department of Dermatology, Helsinki University Central Hospital and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
- Departments of Clinical Science and Education and Section of Dermatology, Karolinska Institutet at Stockholm Söder Hospital, Stockholm, Sweden
- * E-mail:
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21
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Gjymishka A, Palii SS, Shan J, Kilberg MS. Despite increased ATF4 binding at the C/EBP-ATF composite site following activation of the unfolded protein response, system A transporter 2 (SNAT2) transcription activity is repressed in HepG2 cells. J Biol Chem 2008; 283:27736-27747. [PMID: 18697751 PMCID: PMC2562058 DOI: 10.1074/jbc.m803781200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 07/16/2008] [Indexed: 12/20/2022] Open
Abstract
The activated amino acid response (AAR) and unfolded protein response (UPR) stress signaling pathways converge at the phosphorylation of translation initiation factor eIF2alpha. This eIF2alpha modification suppresses global protein synthesis but enhances translation of selected mRNAs such as that for activating transcription factor 4 (ATF4). An ATF4 target gene, SNAT2 (system A sodium-dependent neutral amino acid transporter 2), contains a C/EBP-ATF site that binds ATF4 and triggers increased transcription during the AAR. However, the present studies show that despite increased ATF4 binding to the SNAT2 gene during UPR activation in HepG2 human hepatoma cells, transcription activity was not enhanced. Hyperacetylation of histone H3 and recruitment of the general transcription factors at the HepG2 SNAT2 promoter occurred in response to the AAR but not the UPR. In contrast, the UPR did enhance transcription from a plasmid-based reporter gene driven by a SNAT2 genomic fragment containing the C/EBP-ATF site. Simultaneous activation of the AAR and the UPR pathways revealed that the UPR actually suppressed the increased SNAT2 transcription by the AAR pathway, demonstrating that the UPR pathway generates a repressive signal that acts downstream of ATF4 binding.
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Affiliation(s)
- Altin Gjymishka
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610
| | - Stela S Palii
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610
| | - Jixiu Shan
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610
| | - Michael S Kilberg
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610.
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22
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Thiaville MM, Dudenhausen EE, Awad KS, Gjymishka A, Zhong C, Kilberg MS. Activated transcription via mammalian amino acid response elements does not require enhanced recruitment of the Mediator complex. Nucleic Acids Res 2008; 36:5571-80. [PMID: 18757893 PMCID: PMC2553592 DOI: 10.1093/nar/gkn538] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
It is unclear whether Mediator complex in yeast is necessary for all RNA polymerase II (Pol II) transcription or if it is limited to genes activated by environmental stress. In mammals, amino acid limitation induces SNAT2 transcription through ATF4 binding at an amino acid response element. ATF4 is the functional counterpart to the yeast amino acid-dependent regulator GCN4 and GCN4 recruits Mediator during transcriptional activation. Consistent with enhanced SNAT2 transcription activity, the present data demonstrate that amino acid limitation increased SNAT2 promoter association of the general transcription factors that make up the preinitiation complex, including Pol II, but there was no increase in Mediator recruitment. Furthermore, siRNA knockdown of eight Mediator subunits caused no significant decrease in SNAT2 transcription. The estrogen-dependent pS2 gene was used as a positive control for both the ChIP and the siRNA approaches and the data demonstrated the requirement for Mediator recruitment. These results document that activation of the SNAT2 gene by the mammalian amino acid response pathway occurs independently of enhanced Mediator recruitment.
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Affiliation(s)
- Michelle M Thiaville
- Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA
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23
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Chérasse Y, Maurin AC, Chaveroux C, Jousse C, Carraro V, Parry L, Deval C, Chambon C, Fafournoux P, Bruhat A. The p300/CBP-associated factor (PCAF) is a cofactor of ATF4 for amino acid-regulated transcription of CHOP. Nucleic Acids Res 2007; 35:5954-65. [PMID: 17726049 PMCID: PMC2034469 DOI: 10.1093/nar/gkm642] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
When an essential amino acid is limited, a signaling cascade is triggered that leads to increased translation of the ‘master regulator’, activating transcription factor 4 (ATF4), and resulting in the induction of specific target genes. Binding of ATF4 to the amino acid response element (AARE) is an essential step in the transcriptional activation of CHOP (a CCAAT/enhancer-binding protein-related gene) by amino acid deprivation. We set out to identify proteins that interact with ATF4 and that play a role in the transcriptional activation of CHOP. Using a tandem affinity purification (TAP) tag approach, we identified p300/CBP-associated factor (PCAF) as a novel interaction partner of ATF4 in leucine-starved cells. We show that the N-terminal region of ATF4 is required for a direct interaction with PCAF and demonstrate that PCAF is involved in the full transcriptional response of CHOP by amino acid starvation. Chromatin immunoprecipitation analysis revealed that PCAF is engaged on the CHOP AARE in response to amino acid starvation and that ATF4 is essential for its recruitment. We also show that PCAF stimulates ATF4-driven transcription via its histone acetyltransferase domain. Thus PCAF acts as a coactivator of ATF4 and is involved in the enhancement of CHOP transcription following amino acid starvation.
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Affiliation(s)
- Yoan Chérasse
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Anne-Catherine Maurin
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Cédric Chaveroux
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Céline Jousse
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Valérie Carraro
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Laurent Parry
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Christiane Deval
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Christophe Chambon
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Pierre Fafournoux
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
| | - Alain Bruhat
- UMR 1019 of Human Nutrition and Proteomic core facility, INRA de Theix, 63122 Saint Genès Champanelle, France
- *To whom correspondence should be addressed. +33 4 73 62 41 50+33 4 73 62 47 55
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24
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Oufattole M, Lin SWJ, Liu B, Mascarenhas D, Cohen P, Rodgers BD. Ribonucleic acid polymerase II binding subunit 3 (Rpb3), a potential nuclear target of insulin-like growth factor binding protein-3. Endocrinology 2006; 147:2138-46. [PMID: 16455777 DOI: 10.1210/en.2005-1269] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IGF-binding protein (IGFBP)-3 has intrinsic antiproliferative and proapoptotic functions that are independent of IGF binding and may involve nuclear localization. We determined that exogenous IGFBP-3 rapidly translocates to myoblast nuclei and that a 22-residue peptide containing the metal binding domain (MBD) and nuclear localization sequence (NLS) can similarly direct chimeric GFP into myoblast nuclei. Furthermore, a non-IGF-binding IGFBP-3 mutant inhibited myoblast proliferation without stimulating apoptosis. These results suggest that IGFBP-3 inhibits muscle cell growth in an IGF-independent manner that may be influenced by its rapid nuclear localization. We therefore identified IGFBP-3 interacting proteins by screening a rat L6 myoblast cDNA library using the yeast two-hybrid assay and two N-terminal deletion mutants as bait: BP3/231 (231 residues, L61 to K291) and BP3/111 (K181-K291). Proteins previously known to interact with IGFBP-3 as well as several novel proteins were identified, including RNA polymerase II binding subunit 3 (Rpb3). The domain necessary for Rpb3 binding was subsequently identified using different IGFBP-3 deletion mutants and was localized to the MBD/NLS epitope. Rpb3/IGFBP-3 binding was confirmed by coimmunoprecipitation assays with specific antisera, whereas a NLS mutant IGFBP-3 did not associate with Rpb3, suggesting that a functional NLS is required. Rpb3 facilitates recruitment of the polymerase complex to specific transcription factors and is necessary for the transactivation of many genes. Its association with IGFBP-3 provides a functional role for IGFBP-3 in the direct modulation of gene transcription.
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Affiliation(s)
- Mohammed Oufattole
- Department of Animal Sciences, Washington State University, Pullman, 99164-6351, USA
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25
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Hogan MR, Cockram GP, Lu R. Cooperative interaction of Zhangfei and ATF4 in transactivation of the cyclic AMP response element. FEBS Lett 2005; 580:58-62. [PMID: 16343488 DOI: 10.1016/j.febslet.2005.11.046] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 11/14/2005] [Accepted: 11/18/2005] [Indexed: 12/22/2022]
Abstract
Zhangfei (ZF) is a basic region-leucine zipper protein that has been implicated in herpesvirus infection cycle and related cellular processes. Here we show both in vivo and in vitro data demonstrating that ZF is a novel cellular binding partner of activating transcription factor 4 (ATF4) (or CREB2). We found that ZF competed with ATF4 to form ATF4-ZF heterodimeric complexes through the bZIP regions. ZF enhanced ATF4 binding to the cAMP response element (CRE), and augmented activation of a CRE reporter by ATF4, in response to MEK1 activation. These results suggest an important role of ZF in the MEK1-ATF4 signaling pathway.
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Affiliation(s)
- Melissa R Hogan
- Department of Molecular and Cellular Biology, University of Guelph, Axelrod Building, Room 334, 50 Stone Road East, Guelph, Ont., Canada N1G 2W1
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Corbi N, Bruno T, De Angelis R, Di Padova M, Libri V, Di Certo MG, Spinardi L, Floridi A, Fanciulli M, Passananti C. RNA Polymerase II subunit 3 is retained in the cytoplasm by its interaction with HCR, the psoriasis vulgaris candidate gene product. J Cell Sci 2005; 118:4253-60. [PMID: 16141233 DOI: 10.1242/jcs.02545] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Here, we show that the subcellular localization of α-like RNA polymerase II core subunit 3 (RPB3) is regulated during muscle differentiation. We have recently demonstrated that the expression of RPB3 is regulated during muscle differentiation and that, inside RNA polymerase II (RNAP II), it is directly involved in contacting regulatory proteins such as the myogenic transcription factor Myogenin and activating transcription factor ATF4. We show for the first time, that RPB3, in addition to its presence and role inside the RNAP II core enzyme, accumulates in the cytoplasm of cycling myogenic cells and migrates to the nucleus upon induction of the differentiation program. Furthermore, using human RPB3 as bait in a yeast two-hybrid system, we have isolated a novel RPB3 cytoplasmic interacting protein, HCR. HCR, previously identified as α-helix coiled-coil rod homologue, is one of the psoriasis vulgaris (PV) candidate genes. In cycling myogenic C2C7 cells, we show that the RPB3 protein directly interacts with HCR within the cytoplasm. Finally, knocking down HCR expression by RNA interference, we demonstrate that HCR acts as cytoplasmic docking site for RPB3.
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Affiliation(s)
- Nicoletta Corbi
- Istituto di Biologia e Patologia Molecolari CNR, Universita' di Roma La Sapienza, P. le A. Moro, 5, 00185 Roma, Italy
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27
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Chen H, Pan YX, Dudenhausen EE, Kilberg MS. Amino acid deprivation induces the transcription rate of the human asparagine synthetase gene through a timed program of expression and promoter binding of nutrient-responsive basic region/leucine zipper transcription factors as well as localized histone acetylation. J Biol Chem 2004; 279:50829-39. [PMID: 15385533 DOI: 10.1074/jbc.m409173200] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of human asparagine synthetase (ASNS), which catalyzes asparagine and glutamate biosynthesis, is transcriptionally induced following amino acid deprivation. Previous overexpression and electrophoresis mobility shift analysis showed the involvement of the transcription factors ATF4, C/EBPbeta, and ATF3-FL through the nutrient-sensing response element-1 (NSRE-1) within the ASNS promoter. Amino acid deprivation caused an elevated mRNA level for ATF4, C/EBPbeta, and ATF3-FL, and the present study established that the nuclear protein content for ATF4 and ATF3-FL were increased during amino acid limitation, whereas C/EBPbeta-LIP declined slightly. The total amount of C/EBPbeta-LAP protein was unchanged, but changes in the distribution among multiple C/EBPbeta-LAP forms were observed. Overexpression studies established that ATF4, ATF3-FL, and C/EBPbeta-LAP could coordinately modulate the transcription from the human ASNS promoter. Chromatin immunoprecipitation demonstrated that amino acid deprivation increased ATF3-FL, ATF4, and C/EBPbeta binding to the ASNS promoter and enhanced promoter association of RNA polymerase II, TATA-binding protein, and TFIIB of the general transcription machinery. A time course revealed a markedly different temporal order of interaction between these transcription factors and the ASNS promoter. During the initial 2 h, there was a 20-fold increase in ATF4 binding and a rapid increase in histone H3 and H4 acetylation, which closely paralleled the increased transcription rate of the ASNS gene, whereas the increase in ATF3-FL and C/EBPbeta binding was considerably slower and more closely correlated with the decline in transcription rate between 2 and 6 h. The data suggest that ATF3-FL and C/EBPbeta act as transcriptional suppressors for the ASNS gene to counterbalance the transcription rate activated by ATF4 following amino acid deprivation.
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Affiliation(s)
- Hong Chen
- Department of Biochemistry and Molecular Biology, Genetics Institute, and Shands Cancer Center, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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