Murine hematopoietic progenitor cell lines with erythroid and megakaryocyte potential.

Red blood cells and platelets derive from bi-potential bone marrow megakaryocyte-erythroid progenitors, but their study is constrained by cell scarcity and limited experimental systems. Here we show that conditional expression of a virally transduced, regulated form of Hoxa7 enables expansion of murine cells resembling megakaryocyte-erythroid progenitors (Hoxa7-TPO), which undergo erythro-megakaryocytic differentiation upon Hoxa7 inactivation. The close relationship of Hoxa7-TPO cells to megakaryocyte-erythroid progenitors is supported by genetic and phenotypic analyses, and mature Hoxa7-TPO-derived red blood cells and platelets are largely indistinguishable from their primary counterparts. Genetic knock-out studies in Hoxa7-TPO cells recapitulate the key function of Klf1 and Nfe2 in red blood cell and platelet development, respectively, while disruption of the von Willebrand receptor gene Gp1ba recapitulates features of human Bernard-Soulier syndrome. Hence, we developed a versatile experimental system for expansion and differentiation of megakaryocyte-erythroid progenitors to study red blood cell and platelet development and model human diseases.