Analysis of the thrombopoietin receptor (MPL) promoter implicates GATA and Ets proteins in the coregulation of megakaryocytespecific genes. Blood 87:4678–4685

The MPL gene codes for the thrombopoietin receptor, whose ligand specifically controls megakaryocytic differentiation. To understand the molecular basis for the megakaryocyte-specific expression of MPL, we analyzed the promoter of this gene. A 200 bp fragment is sufficient for high-level specific expression. This fragment can bind several trans-acting fac-tors in vitro, including GATA-1 and members of the Ets fam-ily. GATA-1 binds with low affinity to a unique GATA motif at-70 in the MPL promoter, and destruction of this site yields only a modest decrease in expression level in HEL cells. Ets proteins also bind with low affinity to two sites. One is located at position-15 and its destruction reduces HE MPL GENE is the cellular homologue of the murine T v-mpl oncogene. This oncogene was found in the ge-nome of the murine myeloproliferative leukemia virus, which induces a broad spectrum of myeloid leukemia i