TABLE 5.

Vpr does not affect UDS following UV irradiation of COS cells^a

Virus stock	[3H]-thymidine incorporated (mean cpm)
	No UV irradiation	UV irradiated
Mock	4,508	8,219
Vpr	4,260	8,933
VprX	4,299	9,675

^aCOS cells (2 × 10⁵) were either mock infected or infected with HIV-1_NL4-3-thyenv(−)/VSV-G (Vpr) or HIV-1_NL4-3-thyvprXenv(−)/VSV-G (VprX). At 16 h postinfection, the cells were exposed to UV light (30 J/m²), after which [³H]thymidine (50 μCi/ml) was added for 2 h prior to harvest. Hydroxyurea (10 mM) was added to the culture medium from 1 h prior to UV irradiation until the time of harvest. The harvested cells were lysed, placed on a filter, and counted for levels of [³H]thymidine incorporation. This experiment was repeated twice with similar results.