Gene expression changes in response to activation of Vdr. Lin^neg cKit⁺CD71^lo/neg cells were cultured for 2 days under progenitor conditions (PM) and then transferred to maturation conditions (MM) with or without calcitriol. Total RNA was isolated at the indicated times and analyzed (3.3 ng), using real-time RT-PCR. Expression was normalized to Ubb. (A) Expression of the Vdr target gene Cyp24a1. (B) Expression of the erythroid transcription factor genes Gata1, Fog1, and Klf1. (C) Expression of α- and β-like globins and Alas2. n > 4 experiments. Data were analyzed using a 2-way ANOVA (*P < .05). Error bars, ± SEM.