Effects of YB-1 expression on Tip110/Tat-mediated transactivation of the HIV-1 LTR promoter. 293T cells were transfected with 100 ng of pLTR-CAT and various combinations of pTat-Myc, pTip110-HA, pYB-1-Myc, or each of YB-1 mutants. Input amounts of plasmids were shown at the top, all were in micrograms (μg) with the except of pTat-Myc in nanograms (ng). pTat-Myc plasmid Cells were harvested 72 hr post transfection for the CAT reporter gene activity assay. pcDNA3 plasmid was added to equalize the total amount of DNA transfected, while pC3-GFP plasmid was used to ensure the transfection efficiency among transfections. The data were mean ± SD and representative of at least three independent experiments.