Deficiencies in progenitor cells of multiple hematopoietic lineages and defective megakaryocytopoiesis in mice lacking the thrombopoietin receptor c-Mpl

Abstract

Mice with a null mutation in the thrombopoietin (TPO) receptor C-Mpl were generated by gene targeting. c-mpl-deficient mice developed normally but were deficient in megakaryocytes and severely thrombocytopenic. The hematocrit and numbers of mature circulating leukocytes were normal in mpl-/- mice, as was the distribution of morphologically identifiable precursors in hematopoietic tissues. Bone marrow and spleen cells of adult mpl-/- mice lacked specific binding sites for TPO, were unresponsive to TPO in culture, and displayed a marked deficiency in progenitor cells with megakaryocytic potential. Significantly, total hematopoietic progenitor cell numbers were also reduced in mpl-/- mice, incl..