Retrovirology (Dec 2009)

Inhibition of HIV-1 integrase nuclear import and replication by a peptide bearing integrase putative nuclear localization signal

  • Waigmann Elisabeth,
  • Graessmann Adolf,
  • Melamed-Book Naomi,
  • Rosenbluh Joseph,
  • Armon-Omer Ayelet,
  • Levin Aviad,
  • Loyter Abraham

DOI
https://doi.org/10.1186/1742-4690-6-112
Journal volume & issue
Vol. 6, no. 1
p. 112

Abstract

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Abstract Background The integrase (IN) of human immunodeficiency virus type 1 (HIV-1) has been implicated in different steps during viral replication, including nuclear import of the viral pre-integration complex. The exact mechanisms underlying the nuclear import of IN and especially the question of whether it bears a functional nuclear localization signal (NLS) remain controversial. Results Here, we studied the nuclear import pathway of IN by using multiple in vivo and in vitro systems. Nuclear import was not observed in an importin α temperature-sensitive yeast mutant, indicating an importin α-mediated process. Direct interaction between the full-length IN and importin α was demonstrated in vivo using bimolecular fluorescence complementation assay (BiFC). Nuclear import studies in yeast cells, with permeabilized mammalian cells, or microinjected cultured mammalian cells strongly suggest that the IN bears a NLS domain located between residues 161 and 173. A peptide bearing this sequence -NLS-IN peptide- inhibited nuclear accumulation of IN in transfected cell-cycle arrested cells. Integration of viral cDNA as well as HIV-1 replication in viral cell-cycle arrested infected cells were blocked by the NLS-IN peptide. Conclusion Our present findings support the view that nuclear import of IN occurs via the importin α pathway and is promoted by a specific NLS domain. This import could be blocked by NLS-IN peptide, resulting in inhibition of viral infection, confirming the view that nuclear import of the viral pre-integration complex is mediated by viral IN.