FIG. 2.

Virion-associated Vpr induces a transient cell cycle arrest at G₂. Jurkat T cells were infected with VSV-G-pseudotyped Vpr⁻ Vpr⁺ or Vpr⁺-T HIV. At 20 and 40 h p.i., the cell-associated DNA content of mock-infected and virus-infected Jurkat T cells was analyzed by PI staining as described in Materials and Methods. (A) Histograms of flow cytometric analysis of DNA content in mock-infected cells as well as in all pseudotyped virus-infected cells. The ability of each virus to induce G₂ arrest was determined by calculating the G₂-M/G₁ ratio. (B) In parallel, at different times, p.i., the number of viable cells was counted by the trypan blue exclusion assay. The values represent means of duplicated samples. Similar results were obtained in three independent experiments.