Abstract
DNA damage is a universal inducer of cell cycle arrest at the G2 phase. Infection by the human immunodeficiency virus type 1 (HIV-1) also blocks cellular proliferation at the G2 phase. The HIV-1 accessory gene vpr encodes a conserved 96-amino acid protein (Vpr) that is necessary and sufficient for the HIV-1-induced block of cellular proliferation. In the present study, we examined a recently identified DNA damage-signaling protein, the ATM- and Rad3-related protein, ATR, for its potential role in the induction of G2 arrest by Vpr. We show that inhibition of ATR by pharmacological inhibitors, by expression of the dominant-negative form of ATR, or by RNA interference inhibits Vpr-induced cell cycle arrest. As with DNA damage, activation of ATR by Vpr results in phosphorylation of Chk1. This study provides conclusive evidence of activation of the ATR-initiated DNA damage-signaling pathway by a viral gene product. These observations are important toward understanding how HIV infection promotes cell cycle disruption, cell death, and ultimately, CD4+ lymphocyte depletion.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Antineoplastic Agents / pharmacology
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Antineoplastic Agents, Phytogenic / pharmacology
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Ataxia Telangiectasia Mutated Proteins
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CD4-Positive T-Lymphocytes / virology
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Caffeine / pharmacology
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Cell Cycle
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Cell Cycle Proteins / metabolism*
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Cell Division
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Cell Line, Transformed
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Chromones / pharmacology
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DNA Damage*
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Doxorubicin / pharmacology
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Enzyme Inhibitors / pharmacology
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G2 Phase
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Gene Products, vpr / metabolism*
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Genes, Dominant
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Genetic Vectors
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HIV Infections / virology
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HeLa Cells
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Humans
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Immunoblotting
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Luciferases / metabolism
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Morpholines / pharmacology
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Paclitaxel / pharmacology
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Phosphorylation
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Plasmids / metabolism
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Protein Serine-Threonine Kinases*
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RNA Interference
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Signal Transduction
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Transfection
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vpr Gene Products, Human Immunodeficiency Virus
Substances
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Antineoplastic Agents
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Antineoplastic Agents, Phytogenic
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Cell Cycle Proteins
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Chromones
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Enzyme Inhibitors
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Gene Products, vpr
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Morpholines
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vpr Gene Products, Human Immunodeficiency Virus
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Caffeine
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Doxorubicin
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Luciferases
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ATR protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases
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Paclitaxel