FIGURE 3.
Depletion of eRF1 protein promotes PRF of replication-competent virus. A, strategy for analyzing the effect of eRF1 knockdown on PRF of replication-competent HIV-1 in HeLaT4 cells. Replication-competent HIV-1NL4-3 was used to infect HeLaT4 cells in which eRF1 was knocked down with eRF1-specific siRNAs beforehand. Forty-eight hours after infection, supernatant was harvested from infected cells, and RT levels (for pol gene expression) were obtained by measuring enzymatic activity and normalizing to known amounts of RT protein while p24 levels (for gag gene expression) were assessed via ELISA. Relative frameshifting ratios were determined by dividing the RT concentrations by the p24 concentrations, normalizing to control samples treated with scrambled duplex (SD). B, relative frameshifting ratios obtained. Each value was averaged from three independent samples. Error bars, ±S.D.