Hbz-specific shRNA lentiviral plasmid vectors knock down HBZ protein expression transiently. 293T cells (10⁵) were cotransfected with 0.2 μg HBZ cDNA expression vector and 1.0 μg shRNA lentiviral vector as indicated (V1-V5). Cellular lysates were harvested at 24- and 48-hour time points and subjected to Western blot analysis to detect HBZ, GFP, and β-actin. β-actin and GFP levels were used as internal loading and transfection normalization controls, respectively.