Cellular cofactors and HIV-1 infection in vivo

Inhibitory function of adapter-related protein complex 2 alpha 1 subunit in the process of nuclear translocation of human immunodeficiency virus type 1 genome

The transfection of human cells with siRNA against adapter-related protein complex 2 alpha 1 subunit (AP2alpha) was revealed to significantly up-regulate the replication of human immunodeficiency virus type 1 (HIV-1). This effect was confirmed by cell infection with vesicular stomatitis virus G protein-pseudotyped HIV-1 as well as CXCR4-tropic and CCR5-tropic HIV-1. Viral adsorption, viral entry and reverse transcription processes were not affected by cell transfection with siRNA against AP2alpha. In contrast, viral nuclear translocation as well as the integration process was significantly up-regulated in cells transfected with siRNA against AP2alpha. Confocal fluorescence microscopy revealed that a subpopulation of AP2alpha was not only localized in the cytoplasm but was also partly co-localized with lamin B, importin beta and Nup153, implying that AP2alpha negatively regulates HIV-1 replication in the process of nuclear translocation of viral DNA in the cytoplasm or the perinuclear region. We propose that AP2alpha may be a novel target for disrupting HIV-1 replication in the early stage of the viral life cycle.

Identification of the suppressive factors for human immunodeficiency virus type-1 replication using the siRNA mini-library directed against host cellular genes

We performed the screening to find the novel host factors affecting human immunodeficiency virus type-1 (HIV-1) replication using the siRNA mini-library consisted with 257 siRNAs directed against cellular genes. J111 cells, a human acute monocytic leukemia cell line, were transfected with individual siRNA, followed by either infected or transfected with the HIV-1 molecular clone with luciferase reporter gene in 96-well plate format. The results showed that six siRNAs significantly enhanced the HIV-1 replication in J111 cells, indicating that the target cellular genes of those siRNAs may negatively regulate HIV-1 replication in normal cell culture condition. We also discuss the possible mechanisms by which those cellular proteins regulate viral replication.