Inverse relationship between Glut1 and Glut4 expression during neonatal erythropoiesis is associated with a decreased SP3/SP1 ratio. (A) Ter119⁺/CD71^lo erythroblasts isolated from splenocytes of 6-day-old mice are indicated in the dot plot and surface Glut1 expression was assessed as shown in the histogram. Glut1⁺ and Glut1⁻ erythroblasts were FACS-sorted and the Glut1 profiles of the 2 sorted populations are shown. (B) Glut1 and Glut4 mRNA levels in the sorted Glut1⁺ and Glut1⁻ erythroblasts were assessed by qRT-PCR using the respective primers and normalized to actin. Means plus SD are shown. (C) Expression of the Sp1 and Sp3 zinc-finger transcription factors was assessed in the Glut1⁻ and Glut1⁺ erythroblast subsets by qRT-PCR and normalized to actin. Means plus SD are shown.