Disease relevance of IPO7

• Depletion of importin 7 from cultured cells by small interfering RNA inhibits HIV-1 infection [1].
• Importin 7 may be dispensable for human immunodeficiency virus type 1 and simian immunodeficiency virus infection of primary macrophages [2].
• Using a vesicular stomatitis virus G glycoprotein pseudotyped HIV single-cycle replication system, we showed that the IN/Imp7 interaction-deficient mutant was unable to mediate viral replication and displayed impairment at both viral reverse transcription and nuclear import steps [3].

High impact information on IPO7

• We have studied nuclear import of purified HIV-1 RTCs in primary macrophages and found that importin 7, an import receptor for ribosomal proteins and histone H1, is involved in the process [1].
• Nuclear import of HIV-1 intracellular reverse transcription complexes is mediated by importin 7 [1].
• The importin beta/importin 7 heterodimer is a functional nuclear import receptor for histone H1 [4].
• RanBP7 binds directly to nuclear pore complexes where it competes for binding sites with importin-beta, transportin, and apparently also with the mediators of mRNA and U snRNA export [5].
• Furthermore, we provide evidence for a Ran-dependent transport cycle of RanBP7 and demonstrate that RanBP7 can cross the nuclear envelope rapidly and in both directions [5].

Biological context of IPO7

• On the basis of these results, we propose that RanBP7 might represent a nuclear transport factor that carries an as yet unknown cargo, which could apply as well for this entire class of related RanGTP-binding proteins [5].
• Using RNA interference technology, we inhibited expression of IPO7 by 80 to 95% in primary macrophages and in HeLa cells and monitored their ability to support HIV-1 and simian immunodeficiency virus (SIV) cDNA synthesis, nuclear translocation, and infection efficiency [2].

References