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Homiski C, Dey-Rao R, Shen S, Qu J, Melendy T. DNA damage-induced phosphorylation of a replicative DNA helicase results in inhibition of DNA replication through attenuation of helicase function. Nucleic Acids Res 2024:gkae663. [PMID: 39126317 DOI: 10.1093/nar/gkae663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 06/14/2024] [Accepted: 07/18/2024] [Indexed: 08/12/2024] Open
Abstract
A major function of the DNA damage responses (DDRs) that act during the replicative phase of the cell cycle is to inhibit initiation and elongation of DNA replication. It has been shown that DNA replication of the polyomavirus, SV40, is inhibited and its replication fork is slowed by cellular DDR responses. The inhibition of SV40 DNA replication is associated with enhanced DDR kinase phosphorylation of SV40 Large T-antigen (LT), the viral DNA helicase. Mass spectroscopy was used to identify a novel highly conserved DDR kinase site, T518, on LT. In cell-based assays expression of a phosphomimetic form of LT at T518 (T518D) resulted in dramatically decreased levels of SV40 DNA replication, but LT-dependent transcriptional activation was unaffected. Purified WT and LT T518D were analyzed in vitro. In concordance with the cell-based data, reactions using SV40 LT-T518D, but not T518A, showed dramatic inhibition of SV40 DNA replication. A myriad of LT protein-protein interactions and LT's biochemical functions were unaffected by the LT T518D mutation; however, LT's DNA helicase activity was dramatically decreased on long, but not very short, DNA templates. These results suggest that DDR phosphorylation at T518 inhibits SV40 DNA replication by suppressing LT helicase activity.
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Affiliation(s)
- Caleb Homiski
- Departments of Microbiology & Immunology and Biochemistry, and the Witebsky Center for Microbial Pathogenesis & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY 14203, USA
| | - Rama Dey-Rao
- Departments of Microbiology & Immunology and Biochemistry, and the Witebsky Center for Microbial Pathogenesis & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY 14203, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY 14203, USA; NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY 14203, USA; NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Thomas Melendy
- Departments of Microbiology & Immunology and Biochemistry, and the Witebsky Center for Microbial Pathogenesis & Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY 14203, USA
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Replication of JC Virus DNA in the G144 Oligodendrocyte Cell Line Is Dependent Upon Akt. J Virol 2017; 91:JVI.00735-17. [PMID: 28768870 DOI: 10.1128/jvi.00735-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/26/2017] [Indexed: 12/24/2022] Open
Abstract
Progressive multifocal leukoencephalopathy (PML) is an often-fatal demyelinating disease of the central nervous system. PML results when oligodendrocytes within immunocompromised individuals are infected with the human JC virus (JCV). We have identified an oligodendrocyte precursor cell line, termed G144, that supports robust levels of JCV DNA replication, a central part of the JCV life cycle. In addition, we have determined that JC virus readily infects G144 cells. Furthermore, we have determined that JCV DNA replication in G144 cells is stimulated by myristoylated (i.e., constitutively active) Akt and reduced by the Akt-specific inhibitor MK2206. Thus, this oligodendrocyte-based model system will be useful for a number of purposes, such as studies of JCV infection, establishing key pathways needed for the regulation of JCV DNA replication, and identifying inhibitors of this process.IMPORTANCE The disease progressive multifocal leukoencephalopathy (PML) is caused by the infection of particular brain cells, termed oligodendrocytes, by the JC virus. Studies of PML, however, have been hampered by the lack of an immortalized human cell line derived from oligodendrocytes. Here, we report that the G144 oligodendrocyte cell line supports both infection by JC virus and robust levels of JCV DNA replication. Moreover, we have established that the Akt pathway regulates JCV DNA replication and that JCV DNA replication can be inhibited by MK2206, a compound that is specific for Akt. These and related findings suggest that we have established a powerful oligodendrocyte-based model system for studies of JCV-dependent PML.
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Grubman SA, Shin J, Phelan PJ, Gong A, Can H, Dilworth R, Kini SK, Gagnon D, Archambault J, Meinke G, Bohm A, Jefferson DM, Bullock PA. Isolation of a monoclonal antibody that recognizes the origin binding domain of JCV, but not SV40, large T-antigen. Virology 2016; 497:92-101. [PMID: 27433780 DOI: 10.1016/j.virol.2016.07.006] [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: 05/16/2016] [Revised: 06/27/2016] [Accepted: 07/05/2016] [Indexed: 11/26/2022]
Abstract
Within immunocompromised populations, the JC polyomavirus is the cause of the often-fatal disease Progressive Multifocal Leukoencephalopathy (PML). JC virus encodes a protein, termed T-antigen (T-ag), which is essential for its replication and pathogenicity. Previous studies of JCV T-ag have, in general, used antibodies raised against SV40 T-ag. Unfortunately, SV40 T-ag is also detected in humans and therefore there have been concerns about cross-reactivity. To address this issue, we have isolated a monoclonal antibody that binds to the JCV, but not the SV40, T-ag origin-binding domain (OBD). Furthermore, the region on the surface of the JCV T-ag OBD that is recognized by the "anti-JCV OBD mAb" has been mapped. We also demonstrate that the "anti-JCV OBD mAb" will be a useful reagent for standard techniques (e.g., Westerns blots and ELISAs). Finally, we note that additional monoclonal Abs that are specific for the T-ags encoded by the other human polyomaviruses could be generated by adopting the approach described herein.
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Affiliation(s)
- Shelley A Grubman
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, 02111 MA, USA; Cell Essentials Inc., 75 Kneeland Street, Boston, MA 02111, USA
| | - Jong Shin
- Sackler Institute of Graduate Biomedical Medicine, New York University School of Medicine, 550 First Avenue, New York, NY 10016-6481, USA
| | - Paul J Phelan
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Aaron Gong
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Hande Can
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Ryan Dilworth
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Sandeep Kuntadi Kini
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - David Gagnon
- Institut de Recherches Cliniques de Montreal (IRCM), 110 Pine Avenue West, Montreal, Quebec, Canada H2W 1R7; Department of Biochemistry and Molecular Medicine Universite de Montreal Montreal, Quebec, Canada
| | - Jacques Archambault
- Institut de Recherches Cliniques de Montreal (IRCM), 110 Pine Avenue West, Montreal, Quebec, Canada H2W 1R7; Department of Biochemistry and Molecular Medicine Universite de Montreal Montreal, Quebec, Canada
| | - Gretchen Meinke
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Andrew Bohm
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Douglas M Jefferson
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, 02111 MA, USA
| | - Peter A Bullock
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, 02111 MA, USA.
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Meinke G, Phelan PJ, Shin J, Gagnon D, Archambault J, Bohm A, Bullock PA. Structural Based Analyses of the JC Virus T-Antigen F258L Mutant Provides Evidence for DNA Dependent Conformational Changes in the C-Termini of Polyomavirus Origin Binding Domains. PLoS Pathog 2016; 12:e1005362. [PMID: 26735515 PMCID: PMC4703215 DOI: 10.1371/journal.ppat.1005362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/04/2015] [Indexed: 11/21/2022] Open
Abstract
The replication of human polyomavirus JCV, which causes Progressive Multifocal Leukoencephalopathy, is initiated by the virally encoded T-antigen (T-ag). The structure of the JC virus T-ag origin-binding domain (OBD) was recently solved by X-ray crystallography. This structure revealed that the OBD contains a C-terminal pocket, and that residues from the multifunctional A1 and B2 motifs situated on a neighboring OBD molecule dock into the pocket. Related studies established that a mutation in a pocket residue (F258L) rendered JCV T-ag unable to support JCV DNA replication. To establish why this mutation inactivated JCV T-ag, we have solved the structure of the F258L JCV T-ag OBD mutant. Based on this structure, it is concluded that the structural consequences of the F258L mutation are limited to the pocket region. Further analyses, utilizing the available polyomavirus OBD structures, indicate that the F258 region is highly dynamic and that the relative positions of F258 are governed by DNA binding. The possible functional consequences of the DNA dependent rearrangements, including promotion of OBD cycling at the replication fork, are discussed.
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Affiliation(s)
- Gretchen Meinke
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Paul J. Phelan
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Jong Shin
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York, United States of America
| | - David Gagnon
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, Quebec, Canada
- Department of Biochemistry and Molecular Medicine, Universite de Montreal, Montreal, Quebec, Canada
| | - Jacques Archambault
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, Quebec, Canada
- Department of Biochemistry and Molecular Medicine, Universite de Montreal, Montreal, Quebec, Canada
| | - Andrew Bohm
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Peter A. Bullock
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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