ZBP-89 expression during erythroid ex vivo differentiation of human CD34⁺ cells. (A) Schematic diagram showing time course of culture system used in the experiments. The days of total culture are indicated on top, and days of the individual expansion and differentiation periods are indicated separately on the bottom. (B) Time course of β-, γ-, ϵ-, and α-globin mRNA transcript levels after placing the expanded CD34⁺ cells into erythroid differentiation medium (“Cell culture”). Measurements were made by quantitative RT-PCR and are graphed relative to Gapdh mRNA levels at each time point ± SEM (n > 3). (C) Time course of ZBP-89 mRNA (top) and protein (bottom) levels along the same time course as shown in panel B. mRNA levels are shown relative to those on day 0 of the differentiation culture phase.