FROM THE V-MPL ONCOGENE TO THROMBOPOIETIN

v-mpl is a mouse oncogene that is part of the genome of the myeloproli ferative leukemia virus (MPLV). The cellular homolog gene c-mpl encode s an hematopoietic cytokine receptor restricted to the megakaryocytic lineage of differentiation. Using the Mpl receptor protein, cDNAs corr esponding to the receptor ligand were isolated in humans, pigs, dogs a nd mice. In vivo and in vitro, the recombinant molecule has both the t hrombopoietin (TPO) and megakaryocyte-colony stimulating factor (MK-CS F) activities This molecule (Mpl ligand/TPO/MK-CSF) is the humoral phy siological regulator of platelet production.