Analysis of the thrombopoietin receptor (MPL) promoter implicates GATA and Ets proteins in the coregulation of megakaryocyte-specific genes.
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 factors in vitro, including GATA-1 and members of the Ets family. 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 expression to 50%; the other is located immediately downstream of the GATA motif and plays a crucial role in expression of the promoter in HEL cells, as its inactivation reduces expression to 15%. Furthermore, GATA-1 and two Ets proteins, Ets-1 and Fli-1, can trans-activate the MPL promoter in heterologous cells. The effects of GATA-1 and these two Ets proteins are additive. Together with our previous results on the glycoprotein IIb (GpIIb) promoter, this study indicates a molecular basis for the coregulation of early markers of megakaryocyte differentiation.
Deveaux
S
S
INSERM U. 91, Hôpital Henri Mondor, Créteil, France.
Filipe
A
A
Lemarchandel
V
V
Ghysdael
J
J
Roméo
P H
PH
Mignotte
V
V
D001483:Base Sequence; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D006801:Humans; D008533:Megakaryocytes / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009363:Neoplasm Proteins; D011401:Promoter Regions, Genetic; D050784:Proto-Oncogene Protein c-ets-1; D051789:Proto-Oncogene Protein c-fli-1; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000502:physiology*; D050783:Proto-Oncogene Proteins c-ets; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C494041:ETS1 protein, human; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D009363:Neoplasm Proteins; D050784:Proto-Oncogene Protein c-ets-1; D051789:Proto-Oncogene Protein c-fli-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C082218:MPL protein, human