Abstract
LEDGF/p75 can tether over-expressed lentiviral integrase proteins to chromatin but how this underlies its integration cofactor role for these retroviruses is unclear. While a single integrase binding domain (IBD) binds integrase, a complex N-terminal domain ensemble (NDE) interacts with unknown chromatin ligands. Whether integration requires chromatin tethering per se, specific NDE-chromatin ligand interactions or other emergent properties of LEDGF/p75 has been elusive. Here we replaced the NDE with strongly divergent chromatin-binding modules. The chimeras rescued integrase tethering and HIV-1 integration in LEDGF/p75-deficient cells. Furthermore, chromatin ligands could reside inside or outside the nucleosome core, and could be protein or DNA. Remarkably, a short Kaposi's sarcoma virus peptide that binds the histone 2A/B dimer converted GFP-IBD from an integration blocker to an integration cofactor that rescues over two logs of infectivity. NDE mutants were corroborative. Chromatin tethering per se is a basic HIV-1 requirement and this rather than engagement of particular chromatin ligands is important for the LEDGF/p75 cofactor mechanism.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism*
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Animals
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Antigens, Viral / metabolism
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Antiviral Agents / metabolism
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Base Sequence
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Cell Line
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Cells, Cultured
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Chromatin / metabolism*
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DNA-Binding Proteins / metabolism
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Green Fluorescent Proteins
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HIV Infections / virology*
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HIV Integrase / metabolism
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HIV-1 / metabolism*
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HIV-1 / physiology
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Histones / metabolism
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Humans
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Mice
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Molecular Sequence Data
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Nuclear Proteins / metabolism
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Peptide Fragments / metabolism
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Proteasome Endopeptidase Complex / metabolism
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Protein Binding
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Protein Structure, Tertiary
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RNA Interference
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism*
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Virus Replication
Substances
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Adaptor Proteins, Signal Transducing
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Antigens, Viral
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Antiviral Agents
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Chromatin
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DNA-Binding Proteins
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Histones
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Nuclear Proteins
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PSIP1 protein, human
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Peptide Fragments
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Recombinant Fusion Proteins
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Transcription Factors
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latency-associated nuclear antigen
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Green Fluorescent Proteins
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HIV Integrase
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Proteasome Endopeptidase Complex