rVpr induces L1-RTP in proximal RTECs. A. Detection of rVpr-induced L1-RTP in kidneys. Immunohistochemical analysis using α-GFP was performed. hL1-Tg mice were administered once with 2 μg rVpr intraperitoneally (left four panels) or 250 ng rVpr intravenously (right panels). Upper panels, buffer control; lower panels, rVpr. Green, EGFP-positive cells; blue, Hoechst 33258 staining. Histology after H/E staining was also depicted. Bar, 20 μm (×200). Arrow, EGFP-positive cells. B. Induction of L1-RTP in kidney. Results after six times intravenous injections of 10 ng rVpr were shown. Column 1, buffer control; column 2, rVpr. For each sample, three different slices were prepared and the immunohistochemical analysis was done. Obtained numbers of EGFP-positive cells were then subjected to statistical analysis. P < 0.05. C. rVpr induced L1-RTP was blocked by 4′-Ed4T. Effects of 4′-Ed4T on the induction of L1-RTP by rVpr were examined using #4 hL1-Tg mice. Mice were intravenously injected with 250 ng rVpr six times. To examine the effects of 4′-Ed4T, the compound of 50 μmoles was intraperitoneally injected 2 h prior to injection of rVpr. The inhibitory effects of 4′-Ed4T were statistically significant (P < 0.05). Column 1, buffer; column 2, 250 ng rVpr; column 3, 250 ng rVpr + 4′-Ed4T. D. rVpr induced L1-RTP in proximal RTECs. Double staining with α-AQP1 or α-phalloidin was performed. Bar, 50 μm (×400). hL1-Tg mice were intravenously injected with 10 ng rVpr six times. In this experiment, no EGFP-positive cells were detected in the control kidney of mouse that was injected with buffer.