Relative expression of ABCG2, MDR1,and MRP1 in SP cells.

Three independent SP isolates from 3 independent bone marrow donors were analyzed by RT-PCR. Values for each gene were normalized to a cDNA standard curve generated at the same time, under the same amplification conditions. (A-C) Standard curves for ABCG2, MDR1, and MRP1, respectively. (D) Relative transcript levels for the 3 genes in each of 3 SP isolates. Note that because the standards do not control for reverse transcriptase efficiency, they cannot be used to determine absolute mRNA levels.