Involvement of MAPK in rVpr-induced L1-RTP. A. Inhibition of rVpr-induced L1-RTP by MAPK inhibitors. Before addition of rVpr, SB202190, SP600125 and PD98059, which were inhibitors of p38, JNK and ERK, respectively, were added. Results of the qPCR assay was shown. B. Expression of endogenous C/EBP-β is reduced by siRNA application. See also Additional file 10: Figure S8E showing results obtained by different siRNA. Lane 1, untreated (U); lane 2, mock transfectant (N); lane 3, control siRNA (C); lane 4, C/EBP-β siRNA. C. Inhibition of rVpr-induced L1-RTP by C/EBP-β siRNA. Mr, molecular weight marker. D. c-Jun and CREB were dispensable for rVpr induced L1-RTP. rVpr induced L1-RTP was investigated after the introduction of siRNAs targeting c-Jun and CREB. C/EBP-β siRNA was included as positive control. This experiment was done using C/EBP-β siRNA different from that used in Figures 6B and C. Effects of each siRNA on the expression of endogenous proteins were depicted in Additional file 10: Figures S8F and S8G.