Effect of overexpressed SRSF9 on HIV-1 production in MT-4 cells. MT-4 cells were transfected with 125 ng, 250 ng, 500 ng, or 1 μg flag-tagged SRSF9 expression vector. After 24 h post-transfection, cells were infected with same MOI (200 pg) produced in HEK293T cells by pNL4-3GFP for three days. The cell lysates were subjected to Western blot (A) and the GFP levels were quantified via FACS analysis (B) and measured by fluorescent microscope (C). The asterisks indicate a significant difference from control, analyzed by one-way ANOVA (*P < 0.05, **P < 0.005, and ***P < 0.001).