The Role of Vpr in the Regulation of HIV-1 Gene Expression

The CDK Inhibitor p21Cip1/WAF1Is Induced by FcγR Activation and Restricts the Replication of Human Immunodeficiency Virus Type 1 and Related Primate Lentiviruses in Human Macrophages

“…However, we used one-cycle infection and real-time PCR, while Vazquez et al used a replicative strain of HIV-1 and nonquantitative PCR, which are not ideally suited to analyzing the first steps of viral replication. The increase of p21 expression at late times (14 days) after HIV-1 infection reported by Vazquez et al may be linked to the accumulation of Vpr that stimulates p21 gene expression in infected cells (1,14,17,69) or may be a cell response against stress and apoptotic stimuli associated to infection (3,76). p21 might also have different impacts on HIV-1 infection of macrophages depending on the time since infection: a block of early stages of HIV-1 replication in acute infection, as we show here, or an activation of HIV-1 gene expression, synergistically with Vpr, in chronic infection (17).…”

Human polyomavirus JC small regulatory agnoprotein forms highly stable dimers and oligomers: Implications for their roles in agnoprotein function

“…This protein binds to Rev response elements present in the intron region of the viral transcripts and was found to function as both stable dimers and oligomers as evidenced by 3D structural studies (Daugherty et al, 2010; Daugherty, D’Orso, and Frankel, 2008; Daugherty, Liu, and Frankel, 2010; DiMattia et al, 2010). Like Rev, Vpr also forms stable dimers, arrests cells at G2/M phase transition and induces apoptosis (Bolton and Lenardo, 2007; Cui et al, 2006; Fritz et al, 2008; Fritz et al, 2010; Godet et al, 2010; Iordanskiy et al, 2004; Poon, Chang, and Chen, 2007). Vpr 3D structure has been determined by NMR, showing that the carboxy-terminal helix is responsible for its dimer formation (Bourbigot et al, 2005).…”

Multifaceted activity of HIV Vpr/Vpx proteins: the current view of their virological functions

“…[65]. (f) Trans-activation of proviral LTR [63,64]. (g) and (h) Induction of G 2 arrest [8,[41][42][43][44][45][46][47][48].…”

“…(3) Vpx is essential for viral replication in macrophages and is important for viral replication in T-cells [8,9,[23][24][25][26][27][28][29][30][31]. Additional important functions of HIV Vpr/Vpx so far proposed include the promotion of full-length viral DNA accumulation (HIV-2 Vpx) [9][10][11], nuclear import of viral preintegration complex (HIV-1 Vpr and HIV-2 Vpx) [1,8,23,29,34,35], transcriptional transactivation of viral and cellular promoters (HIV-1 Vpr and HIV-2 Vpr) [63][64][65] and cytopathogenic activity by an unknown mechanism (HIV-2 Vpx) [10,20]. Generally, mutational effects of HIV Vpr on viral replication are smaller than those of HIV-2 Vpx, and therefore, care should be taken to interpret the results of experiments.…”