Regulator of myeloid differentiation and function: The secret life of Ikaros

Figure 2 Overview of Ikaros expression in hematopoiesis. The relative expression levels of Ikaros mRNA in hematopoietic progenitors (light gray box in foreground) are indicated by levels of green shading. Progenitors from both the classic and the LMPP pathways are included. Relative Ikaros expression levels are from studies by Yoshida et al[63] that have used mice with an Ikaros reporter cassette [green fluorescent protein (GFP) down stream of an Ikaros promoter] as an indicator of Ikaros mRNA expression in early stages of murine hematopoiesis. Shown in the dark gray box in the background is the protein level expression of human Ikaros isoforms in differentiated hematopoietic cells and in Lin^-CD34⁺ hematopoietic progenitors as described by Ronniet al[19] and Payne et al[54]. Human cells that express Ik-x and/or Ik-1 also express the plus form of these isoforms[19,54] (i.e. Ik-1⁺/Ik-H and Ik-x⁺, see Figure 1). ¹Mature T cells express little Ikaros protein unless they are activated[19,54]. HSC: Hematopoietic stem cell; LT-HSC: Long-term-HSC; ST-HSC: Short-term-HSC; CMP: Common myeloid progenitor; GMP: Granulocyte/macrophage progenitor; LMPP: Progenitor with lymphoid and myeloid potential; MEP: Megakaryocyte/erythroid progenitor; LP: Lymphoid progenitor; NK: Natural killer.