Figure 2.

Suppression of the inhibitory effect of HIV-1 PR on fission yeast colony formation by FDA-approved PI drugs. (A) Assay controls: PR-off, no HIV-1 PR gene expression. This is the only well in this figure that HIV-1 PR gene was suppressed. All others are HIV-1 PR-producing wells (PR-on); DMSO, DMSO was added to the PR-on well as a mock control because it was used as a solvent to dissolve the PI drugs tested. (B) All single-agent PI drugs tested here were in pure chemical forms. (C) All single-agent PI drugs tested here were extracted from commercially available and formulated drug pills. Inducible expression of HIV-1 PR in fission yeast RE294 strain was achieved by removing thiamine from the growth PMG minimal medium (PR-on). No HIV-1 PR was expressed when 20 μM of thiamine was present in the PMG medium (PR-off) [25]. A total of 150 μM of each drug was added to the 6-well culture plate containing thiamine-free PMG agar. A total of 1 × 10³ RE294 PR-producing cells in the volume of 50 μL were evenly spread onto the surface of the agar culture well using a plastic rod. The 6-well agar culture plates were incubated in the 30 °C incubator. Pictures were taken at 4–5 days after incubation. Data presented represent results of three different experiments.