FIGURE 1.

Erythropoiesis and megakaryopoiesis are regulated at multiple levels. A complex network of extracellular signals -activating intracellular signaling pathways-, cell–cell interactions within the niche and intracellular effectors regulate cell differentiation in homeostatic conditions and in response to stress stimuli (Ferreira et al., 2005; Hattangadi et al., 2011; Songdej and Rao, 2017). These signals converge on TFs and chromatin modifiers which ultimately define the transcriptome at each given stage. The main growth factors, integrins and transcription factors involved in these processes are indicated. The GATA1 (red rectangles) and KLF1 (green rectangles) windows of expression are indicated (see also Figure 2B). HSC, Hematopoietic Stem cell; TPO, thrombopoietin; SCF, Stem cell Factor; IL, interleukin; SDF-1, stromal-derived factor-1; GPIIb/IIIa, integrins α_IIb/β₃ (CD41/CD61); EPO, erythropoietin; GCs, glucocorticoids. α₄/β₁, integrins α₄/β₁ (CD49d/CD29).