c-Maf plays a crucial role for the definitive erythropoiesis that accompanies erythroblastic island formation in the fetal liver

MafB promotes atherosclerosis by inhibiting foam-cell apoptosis

“…Recently, we reported that c-Maf-deficient macrophages fail to form erythroblastic islands, leading to anemia at the embryonic stage due to enucleation defects in erythroblasts. In contrast, the Mafb-deficient embryos do not exhibit a similar anemic phenotype 39 . Overall, these data indicate that MafB and c-Maf play distinct but overlapping roles in macrophages.…”

Extrinsic and intrinsic control by EKLF (KLF1) within a specialized erythroid niche

“…Although an abnormal level of circulating nucleated definitive cells are observed in embryos deficient for the DNASE2A, MAF or palladin macrophage proteins (Kawane et al, 2001;Kusakabe et al, 2011;Liu et al, 2007), ablating the majority of macrophage cells does not automatically yield an abundance of nucleated red cells in circulation (Chow et al, 2013;Ramos et al, 2013). In addition, there are a number of structural, enzymatic and chromatin-associated erythroid cell factors that play an intrinsic role in morphologically preparing the cell for proper nuclear extrusion (Ji et al, 2011;Keerthivasan et al, 2011;Konstantinidis et al, 2012;Ney, 2011;Ubukawa et al, 2012;von Lindern, 2006).…”

“…We compared RNA expression levels of αv integrin (Lee et al, 2006;Mankelow et al, 2004), VCAM1 (Sadahira et al, 1995), EMP (MAEA) (Soni et al, 2006), palladin , MAF (Kusakabe et al, 2011) and DNASE2A (Kawane et al, 2001) between EKLF/GFP+F4/80+ and EKLF/ GFP-F4/80+ sorted singlet cells (supplementary material Fig. S3).…”

“…Extensive macrophage-erythroblast and erythroblast-erythroblast adhesive interactions are necessary for a thriving definitive erythropoietic community. As a result, structural proteins that mediate these interactions (Fabriek et al, 2007;Lee et al, 2006;Liu et al, 2007;Mankelow et al, 2004;Sadahira et al, 1995;Soni et al, 2006) as well as transcriptional factors (Gutiérrez et al, 2004;Iavarone et al, 2004;Kusakabe et al, 2011) are both crucial for promoting an effective differentiative environment. Erythroblasts can proliferate, mature and enucleate in vitro in the absence of other cell types; however, this process is typically very inefficient at all stages (Hanspal et al, 1998;Rhodes et al, 2008).…”

c-Maf rules the island

“…Kusakabe et al now show that the basic region-leucine zipper transcription factor c-Maf is critical for erythroblastic island formation. 1,6 The macrophage is the site of c-Maf activity, and c-Maf deficiency is associated with severe embryonic anemia and lethality. This study opens a new avenue into the investigation of erythroblastic islands.…”