The Ewing's Sarcoma EWS/FLI-1 Fusion Gene Encodes a More Potent Transcriptional Activator and is a More Powerful Transforming Gene than FLI-1

WA May, SL Lessnick, BS Braun, M Klemsz… - … and cellular biology, 1993 - Taylor & Francis
WA May, SL Lessnick, BS Braun, M Klemsz, BC Lewis, LB Lunsford, R Hromas, CT Denny
Molecular and cellular biology, 1993Taylor & Francis
EWS/FLI-1 is a chimeric protein formed by a tumor-specific 11; 22 translocation found in both
Ewing's sarcoma and primitive neuroectodermal tumor of childhood. EWS/FLI-1 has been
shown to be a potent transforming gene, suggesting that it plays an important role in the
genesis of these human tumors. We now demonstrate that EWS/FLI-1 has the characteristics
of an aberrant transcription factor. Subcellular fractionation experiments localized the
EWS/FLI-1 protein to the nucleus of primitive neuroectodermal tumor cells. EWS/FLI-1 …
EWS/FLI-1 is a chimeric protein formed by a tumor-specific 11;22 translocation found in both Ewing’s sarcoma and primitive neuroectodermal tumor of childhood. EWS/FLI-1 has been shown to be a potent transforming gene, suggesting that it plays an important role in the genesis of these human tumors. We now demonstrate that EWS/FLI-1 has the characteristics of an aberrant transcription factor. Subcellular fractionation experiments localized the EWS/FLI-1 protein to the nucleus of primitive neuroectodermal tumor cells. EWS/FLI-1 specifically bound in vitro an ets-2 consensus sequence similarly to normal FLI-1. When coupled to a GAL4 DNA-binding domain, the amino-terminal EWS/FLI-1 region was a much more potent transcriptional activator than the corresponding amino-terminal domain of FLI-1. Finally, EWS/FLI-1 efficiently transformed NIH 3T3 cells, but FLI-1 did not. These data suggest that EWS/FLI-1, functioning as a transcription factor, leads to a phenotype dramatically different from that of cells expressing FLI-1. EWS/FLI-1 could disrupt normal growth and differentiation either by more efficiently activating FLI-1 target genes or by inappropriately modulating genes normally not responsive to FLI-1.
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