MDR1 mRNA expression analysis in wild-type C57BL/6 mice and B-hMDR1 mice by RT-PCR. Liver RNA was isolated from wild-type C57BL/6 mice (+/+) and B-hMDR1 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse Mdr1a, Mdr1b primers and human MDR1 primers. Human MDR1 mRNA was only detectable in B-hMDR1 mice. Mouse Mdr1a and Mdr1b mRNA were only detectable in wild type mice but not in B-hMDR1 mice. 

Western blot analysis of MDR1 protein expression in homozygous B-hMDR1 mice. Various tissue lysates were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hMDR1 mice (H/H), and then analyzed by western blot with anti-MDR1 antibody. 40μg total proteins were loaded for western blotting analysis. MDR1 was detectable in lung, spleen, heart, kidney and brain of wild-type mice and B-hMDR1 mice. Because the antibody used in the experiment has species-cross recognition. Knock-out mice tissue as a negative control. Refer to the mRNA results, the protein in B-hMDR1 mice was expressed by human MDR1 mRNA sequences.