Figure 4: hnRNPs in regulation of hemoglobin expression in erythoid differentiation. Three hnRNP proteins, hnRNP D, E1, and E2, have been suggested to play an important role in the hemoglobin synthesis. All three hnRNP proteins regulate α- or β-globin mRNA levels through stabilising both mRNAs by directly binding to CU-rich elements within 3′UTR of these genes.