EWS.Fli-1 fusion protein interacts with hyperphosphorylated RNA polymerase II and interferes with serine-arginine protein-mediated RNA splicing.
Ewing's sarcoma displays a characteristic chromosomal translocation that results in fusion of the N-terminal domain of the Ewing's sarcoma protein (EWS) to the C-terminal DNA-binding domain of the ETS family transcription factor Fli-1 (Friend leukemia integration-1). EWS possesses structural motifs suggesting a role in transactivation as well as RNA binding. We demonstrate that wild-type EWS protein functions as an adapter molecule coupling transcription to RNA splicing by binding to hyperphosphorylated RNA polymerase II through the N-terminal domain of EWS and recruiting serine-arginine (SR) splicing factors through the C-terminal domain of EWS. The oncogenic EWS.Fli-1 fusion protein retains the ability to bind to hyperphosphorylated RNA polymerase II but lacks the ability to recruit SR proteins because of replacement of the C-terminal domain of EWS by Fli-1. In an in vivo splicing assay, the EWS.Fli-1 fusion protein inhibits SR protein-mediated E1A pre-mRNA splicing in a dominant-negative manner. These results indicate that EWS.Fli-1 interferes with the normal function of EWS and implicate uncoupling of gene transcription from RNA splicing in the pathogenesis of Ewing's sarcoma.
Yang
L
L
Medical Research Service, Veterans Affairs Puget Sound Health Care System, Seattle, Washington 98108, USA.
Chansky
H A
HA
Hickstein
D D
DD
D000818:Animals; D001120:Arginine / Q000378:metabolism*; D019556:COS Cells; D006367:HeLa Cells; D006801:Humans; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D010766:Phosphorylation; D051789:Proto-Oncogene Protein c-fli-1; D012319:RNA Polymerase II / Q000378:metabolism*; D012326:RNA Splicing; D034802:RNA-Binding Protein EWS; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012694:Serine / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors; D012694:Serine; D001120:Arginine; D012319:RNA Polymerase II