The HIV-1 integrase mutant R263A/K264A is 2-fold defective for TRN-SR2 binding and viral nuclear import.
Transportin-SR2 (Tnpo3, TRN-SR2), a human karyopherin encoded by the TNPO3 gene, has been identified as a cellular cofactor of HIV-1 replication, specifically interacting with HIV-1 integrase (IN). Whether this interaction mediates the nuclear import of HIV remains controversial. We previously characterized the TRN-SR2 binding interface in IN and introduced mutations at these positions to corroborate the biological relevance of the interaction. The pleiotropic nature of IN mutations complicated the interpretation. Indeed, all previously tested IN interaction mutants also affected RT. Here we report on a virus with a pair of IN mutations, IN(R263A/K264A), that significantly reduce interaction with TRN-SR2. The virus retains wild-type reverse transcription activity but displays a block in nuclear import and integration, as measured by quantitative PCR. The defect in integration of this mutant resulted in a smaller increase in the number of two-long terminal repeat circles than for virus specifically blocked at integration by raltegravir or catalytic site mutations (IN(D64N/D116N/E152Q)). Finally, using an eGFP-IN-labeled HIV fluorescence-based import assay, the defect in nuclear import was corroborated. These data altogether underscore the importance of the HIV-IN TRN-SR2 protein-protein interaction for HIV nuclear import and validate the IN/TRN-SR2 interaction interface as a promising target for future antiviral therapy.
['De Houwer|Stéphanie|S|', 'Demeulemeester|Jonas|J|', 'Thys|Wannes|W|', 'Rocha|Susana|S|', 'Dirix|Lieve|L|', 'Gijsbers|Rik|R|', 'Christ|Frauke|F|', 'Debyser|Zeger|Z|']
D021581:Active Transport, Cell Nucleus D001665:Binding Sites D001667:Binding, Competitive D015153:Blotting, Western D002467:Cell Nucleus D019427:HIV Integrase D015497:HIV-1 D006367:HeLa Cells D006801:Humans D008958:Models, Molecular D050505:Mutant Proteins D009154:Mutation D011485:Protein Binding D017434:Protein Structure, Tertiary D014779:Virus Replication D028961:beta Karyopherins
TRN-SR2 Nuclear Import TNPO3 HIV Integrase HIV-1 Protease Human Immunodeficiency Virus (HIV) Nuclear Transport Transportin-3 Viral Replication