MPL and anemia (phenotype): However, Mpl–/– Dnm2Plt–/– mice showed severe anemia, erythroblast (EB) maturation defects, decreased expression of hemoglobin and heme homeostasis genes and increased expression of ribosome biogenesis and protein translation genes in spleen EBs, and grossly elevated plasma erythropoietin (EPO) levels, resulting in early fatality by postnatal day 25.