FIG 6.

Sensitivity/resistance to the late IFN-γ-induced block in MT4 cells maps to the env gene. (A) Representations of the chimeric and parental infectious molecular clones of NL4-3 and CH040 used in the experiments shown in panels B to E. The restriction sites used to clone the chimeras are shown. The incoming titer (B), the yield of infectious progeny (C), the mean fold reduction in infectious HIV-1 production (calculated as described in the legend of Fig. 5) (D), and expression levels of the particulate supernatant capsid and cellular Gag/capsid, gp160, and phosphorylated STAT1 (E) were assessed using MT4-R5-LTR-GFP cells in the presence/absence of IFN-γ pretreatment (as well as VSV-G), as described in the legends of Fig. 4 and 5. The Western blots shown in panel E are those from the VSV-G pseudotyped infections to ensure readily measurable Gag expression. An asterisk (*) indicates that pNL-040-BA was reproducibly severely attenuated, and we were unable to detect infection/replication using this clone. Error bars indicate SEM (n = 3 to 5).