GADD34 expression increases the viral yields of a γ34.5-null oHSV. A, Doxycycline (dox)-inducible GADD34 expressing U251 cells (designated as U251.G34) were treated with doxycycline (200 ng/mL) for 24 hours, followed by culture in the presence or absence of 20 μmol/L MG132 for the indicated times (0, 1, 2, and 4 hours). GADD34 and αTubulin were visualized by immunoblots (IB) utilizing the corresponding antibodies. Numbers on the left indicate molecular size (kDa). B, U251.G34 cells were infected by γ34.5-null rHSVQ virus at a multiplicity of infection (MOI) of 0.03 for three days in the presence or absence of doxycycline (200 ng/mL). Data represent the mean with SD of three replicates. Statistical analyses were conducted by Student t test, where ** indicates P < 0.01.