TPO (thrombopoietin) is the key regulator of thrombopoiesis for platelet lineage. In both mice and humans, inactivation of this gene results in significant decrease in number of mature platelets produced by marrow progenitors. Transgenic mice with increased expression of this protein show progressive fibrosis and osteosclerosis of the bone marrow, as well as histological changes in kidneys, leading to mesangioproliferative glomerulopathy.
