ZNF198-FGFR1 transforms Ba/F3 cells to growth factor independence and results in high level tyrosine phosphorylation of STATS 1 and 5.
The ZNF198- FGFR1 fusion gene arises as a result of the t(8;13)(p11;q12) in the 8p11 myeloproliferative syndrome. To determine the transforming properties of this chimeric protein we transfected ZNF198-FGFR1 into the interleukin (IL)-3 dependent cell line Ba/F3. Growth factor independent subclones were obtained in which ZNF198-FGFR1, STAT1, and STAT5 were constitutively tyrosine phosphorylated, as determined by immunoprecipitation and Western blot analysis. To test the hypothesis that constitutive activation of ZNF198-FGFR1 tyrosine kinase activity is a result of self-association of the fusion protein, we in vitro transcribed and translated ZNF198-FGFR1 and a derivative construct, ZNF198- FGFR1deltaC-myc, in which the C-terminal FGFR1 epitope was replaced by a c-myc tag. As expected, an anti-FGFR1 antibody immunoprecipitated ZNF198-FGFR1 but not ZNF198-FGFRdeltaC-myc. However when both products were translated together, both were coimmunoprecipitated by anti-FGFR1 antisera. Similar results were obtained by using an anti-myc antibody and demonstrated a physical interaction between the two proteins. Analysis of COS-7 cells transfected with ZNF198-FGFR1 demonstrated that the fusion gene, in contrast to normal FGFR1, is located in the cytoplasm. We conclude that ZNF198-FGFR1 is a cytoplasmic protein that self-associates and has constitutive transformation activity. These data suggest that ZNF198-FGFR1 plays a primary role in the pathogenesis of the t(8;13) myeloproliferative syndrome and is the first report to implicate STAT proteins in FGFR1-mediated signaling.
Molecular Carcinogenesis Section, Institute of Cancer Research, Haddow Laboratories, Belmont, Surrey, UK.
D
D
Smedley
A
A
Demiroglu
M
M
Abdul-Rauf
C
C
Heath
C
C
Cooper
J
J
Shipley
N C
NC
Cross
D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D007377:Interleukin-3 / Q000378:metabolism; D051379:Mice; D008894:Milk Proteins; D009196:Myeloproliferative Disorders / Q000235:genetics; D010766:Phosphorylation; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D050794:STAT1 Transcription Factor; D050799:STAT5 Transcription Factor; D015398:Signal Transduction; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism*
D004268:DNA-Binding Proteins; D006133:Growth Substances; D007377:Interleukin-3; D008894:Milk Proteins; D016271:Proto-Oncogene Proteins c-myc; D017468:Receptors, Fibroblast Growth Factor; D011993:Recombinant Fusion Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050799:STAT5 Transcription Factor; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D014443:Tyrosine; C496348:FGFR1 protein, human; C496349:Fgfr1 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1