The effect of oligonucleotides on colony formation of normal bone marrow progenitors. Methylcellulose colony assays were performed after oligonucleotide treatment. The oligonucleotides were random (▧), MDR1-S (▧), and MDR1-AS (▪). The results are expressed as the percentage of treated colonies compared with the untreated control. The standard error bars denote the mean ± the SD of the mean of the CFU-GM, CFU-E, BFU-E, and CFU-GEMM. The mean colony numbers of the untreated controls from four experiments were 295 ± 34 for CFU-GM, 408 ± 49 for CFU-E, 99 ± 20 for BFU-E, and 13 ± 6 for CFU-GEMM, respectively.