FIG. 5.

Virion-associated Vpr stimulates HIV LTR-directed CAT gene expression. Jurkat T cells transfected with pCEP4III LTR-CAT were selected with hygromycin (500 μg/ml). After 10 days of selection, hygromycin-resistant Jurkat T cells were infected with VSV-G-pseudotyped Vpr⁻, Vpr⁺, or Vpr⁺-T HIV (as indicated). (A) At 12, 15, and 18 h p.i., CAT activity was determined. The transactivation level in each VSV-G pseudotyped HIV-infected cell sample is expressed as fold increase in CAT activity. The CAT activity value obtained in Vpr⁻-infected Jurkat T cells at 12 h p.i. was arbitrarily set at 1 (A). (B) CAT activity detected in pCEP4III LTR-CAT-transfected Jurkat cells following infection with VSV-G-pseudotyped Vpr⁻, Vpr⁺, Vpr⁺-T, and Vpr^R80A-T viruses. (C and D) Hygromycin-resistant Jurkat cells were infected with VSV-G-pseudotyped Vpr⁻, Vpr⁺, or Vpr⁺-T HIV in the presence (lanes 1 to 4) or absence (lanes 5 to 8) or 5 μM AZT. At 12 h p.i. (C) and 30 h p.i. (D), CAT activity in each VSV-G-pseudotyped, HIV-infected cell sample was measured.