Structure of MRP3 and expression of MRP3 mRNA in glioblastoma-derived cell lines. (A) MRP3 structure. Upper: the organization of MRP3. Lower: membrane topology model for MRP3 (modified from Hipfner et al. ). MAR1, MAR2, MAR3, membrane-associated regions 1-3; L1, L2, linker domains 1 and 2; NBD1, NBD2, nucleotide-binding domains 1 and 2. Positions of PCR primers are indicated by arrows. (B) RT-PCR results showing MRP3 mRNA expression (Upper) and β-actin expression (Lower) in GBM cell lines U251 MG, T98G, D245 MG, D54 MG, D247 MG, and D392 MG.