Oligodeoxynucleotides antisense to the proto-oncogene c-mpl specifically inhibit in vitro megakaryocytopoiesis.
The proto-oncogene c-mpl encodes a protein whose sequence shares striking homologies with members of the highly conserved hematopoietin receptor superfamily. This gene had been transduced in a truncated form by the acute leukemogenic murine Myeloproliferative leukemia virus, which exhibits the unique property of inducing factor-independent proliferation and terminal differentiation of a broad spectrum of hematopoietic progenitors. Presently, the ligand and the role of c-mpl in the regulation of normal hematopoiesis are unknown. To show the function of c-mpl, its expression was first examined in human purified hematopoietic cell populations and, then, an antisense strategy was used. By RNA-based polymerase chain reaction, c-mpl transcripts were detected in purified CD34+ cells, megakaryocytes, and platelets. Synthetic unmodified antisense oligodeoxynucleotides were derived from different regions of the c-mpl extracellular domain. On in vitro exposure of CD34+ cells, two antisense oligomers led to a 50% to 70% inhibition of c-mpl mRNA synthesis, whereas their respective sense had no effect. Furthermore, the decrease in c-mpl mRNA correlated with a significant inhibition (range, 54% to 81%) of in vitro megakaryocytic colony formation (CFU-MK), whereas the growth of erythroid (BFU-E) or granulomacrophage (CFU-GM) colonies was unaffected. The data provide first evidences that c-mpl is involved in megakaryocytopoiesis. In addition, the results raise the possibility that this proto-oncogene encodes the receptor for a new cytokine specifically regulating thrombocytopoiesis.
Methia
N
N
INSERM U 362, Institut Gustave Roussy, Villejuif, France.
Louache
F
F
Vainchenker
W
W
Wendling
F
F
D015703:Antigens, CD / Q000097:blood; D018952:Antigens, CD34; D001483:Base Sequence; D001792:Blood Platelets / Q000187:drug effects / Q000276:immunology; D006410:Hematopoiesis / Q000235:genetics*; D006801:Humans; D007938:Leukemia / Q000235:genetics; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009691:Nucleic Acid Denaturation / Q000187:drug effects; D016376:Oligonucleotides, Antisense / Q000235:genetics* / Q000494:pharmacology; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D011519:Proto-Oncogenes / Q000235:genetics*; D018121:Receptors, Cytokine; D011971:Receptors, Immunologic / Q000235:genetics*; D053628:Receptors, Thrombopoietin; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D018952:Antigens, CD34; C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D011971:Receptors, Immunologic; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human