Expression of the

mdr1a gene in vincristine-treated leukemia cells. (A) Semiquantitative RT-PCR assay. The left panel shows a representative result of CYBR green staining after electrophoresis of PCR product amplified from P-V₂ RT product withmdr1a-specific primers (left panel, upper) pr-1aF and pr-1aR, or β₂-microglobulin–specific primers (left panel, lower) pr-mgF and pr-mgR, in a 3% agarose gel. The gel was analyzed with FAS200 and plotted as a graph (right panel: closed squares, β₂-microglobulin, and closed triangles,mdr1a). The relative mdr1a expression was obtained from the dilution rate at the exponential range in the right panel and normalized by dividing by the dilution rate of β₂-microglobulin. The relative expression ofmdr1a is calculated, for example, as a formula at the bottom. (B) Relative expression of mdr1a in mice. The value of relative expression is presented in the box and plotted as a graph. Closed and open circles indicate the P-V and P-C series, respectively. ND indicates not detected.