EAT-2 IS A NOVEL SH2 DOMAIN-CONTAINING PROTEIN THAT IS UP-REGULATED BY EWINGS-SARCOMA EWS FLI1 FUSION GENE/

The EWS/FLI1 fusion protein is created by the translocation between ch romosomes 11 and 22 that appears in most Ewing's sarcomas, This chimer ic protein has been demonstrated to be an aberrant transcription facto r. Genes up regulated by EWS/FLI1 but not by full-length FLI1 were ide ntified by representational difference analysis (RDA), We have charact erized a novel gene, EWS/FLI1 activated transcript 2 (EAT-2) that was cloned from a murine cDNA library using a differentially expressed RDA fragment. EAT-2 expression is seen within 4-8 h of EWS/FLI1 induction , Its expression correlates with transformation of NIH3T3 cells by chi meric proteins related to EWS/FLI1 but not by unrelated genes, EAT-2 i s expressed in normal murine tissues and contains a unique but biochem ically functional SH2 domain, An homologous sequence in the human geno me has been identified and mapped to chromosome 1q22, Human EAT-2 tran scripts were identified by reverse transcriptase-polymerase chain reac tion (RT-PCR) in Ewing's sarcoma cell tumour cell lines. EAT-2's uniqu e structure and correlation with transformation make it a candidate fo r playing a role in the transformation of NIH3T3 cells and the oncogen esis of Ewing's sarcoma.