Analyses of the functions of miR30-shRNA/Luc in vitro. (a) LV-mCMV/SYN-tTA and (b) LV-mCMV/GfaABC1D-tTA mediated Dox-controllable Luc knock-down in PC12 cells and 1321N1 cells. Dox was used at a concentration of 200 ng/ml. - Dox, cells were cultured in the continuous absence of Dox; + Dox, cells were cultured in the continuous presence of Dox; + - Dox, Dox was administered for 48 h during and after transduction followed by a change to Dox-free medium and culturing for three more days. The results are expressed in RLU per well. A: LVVs-miRLuc-control1; B, C, D: LVVs-miRLuc-neurone A': LVVs-miRLuc-control2; B', C', D': LVVs-miRLuc-glia. *P < 0.01, **P = 0.06, compared with group A. ♦P < 0.01, ♦♦P = 0.84, compared with group A'. In this and the following figures the error bars represent standard deviation.