Effects of different IN mutants on yeast growth. HP16 yeast cells were transformed with the wild type IN and different IN mutant expressors, as indicated. A. Expression of different IN mutants in HP16 yeast cells. Equal amounts of cells were grown in inducible media for 6 hr and cells were collected, lysed and subjected to IP with anti-HIV serum followed by WB with anti-IN antibody (upper panel). Additionally, 1/10 of the yeast cell lysate was analyzed by SDS-PAGE and the endogenous yeast β-actin was detected by anti-actin WB (lower panel). B. Each transformed yeast population was first grown in non-inducible selective media overnight. Then equal amounts of transformed yeast cells were grown either in non-inducible media (upper panel) or in the inducible media (lower panel) at 30°C for 24–36 hr. Yeast growth was monitored by measuring each yeast cell culture density, as previously described. Means and standard deviations from three independent experiments are shown. C. The growth of yeast in the absence of IN expression (left panel) or in the presence of IN expression (right panel) was also tested by the "drop test" on agar plate, as described.