Arvand A, Bastians H, Welford S M, Thompson A D, Ruderman J V, Denny C T
Department of Experimental Pathology/Laboratory Medicine, University of California, Los Angeles, USA.
Oncogene. 1998 Oct 22;17(16):2039-45. doi: 10.1038/sj.onc.1202129.
The EWS/FLI1 fusion gene found in Ewing's sarcoma and primitive neuroectodermal tumor, is able to transform certain cell lines by acting as an aberrant transcription factor. The ability of EWS/FLI1 to modulate gene expression in cells transformed and resistant to transformation by EWS/FLI1, was assessed by Representational Difference Analysis (RDA). We found that the cyclin selective ubiquitin conjugase murine E2-C, was up regulated in NIH3T3 cells transformed by EWS/FLI1 but not in a nontransformed NIH3T3 clone expressing EWS/FLI1. We also found that mE2-C is upregulated in NIH3T3 cells transformed by other genes including activated cdc42, v-ABL and c-myc. We demonstrated that expression of mE2-C in both the EWS/FLI1 transformed and parent NIH3T3 lines varies with the cell cycle. Finally, dominant-negative mE2-C, created by changing a catalytic cysteine to serine, inhibits the in vitro ubiquitination and degradation of cyclin B in human HeLa cell extracts. These data suggest that part of the biologic effect of EWS/FLI1 could be to transcriptionally modulate genes involved in cell cycle regulation.
在尤因肉瘤和原始神经外胚层肿瘤中发现的EWS/FLI1融合基因，能够作为一种异常转录因子来转化某些细胞系。通过代表性差异分析（RDA）评估了EWS/FLI1在被EWS/FLI1转化的细胞以及对EWS/FLI1转化具有抗性的细胞中调节基因表达的能力。我们发现，细胞周期蛋白选择性泛素连接酶小鼠E2-C，在被EWS/FLI1转化的NIH3T3细胞中上调，但在表达EWS/FLI1的未转化NIH3T3克隆中未上调。我们还发现，mE2-C在被包括活化的cdc42、v-ABL和c-myc在内的其他基因转化的NIH3T3细胞中上调。我们证明，在EWS/FLI1转化的NIH3T3细胞系和亲本NIH3T3细胞系中，mE2-C的表达均随细胞周期而变化。最后，通过将催化性半胱氨酸改变为丝氨酸而产生的显性负性mE2-C，抑制了人HeLa细胞提取物中细胞周期蛋白B的体外泛素化和降解。这些数据表明，EWS/FLI1的部分生物学效应可能是转录调节参与细胞周期调控的基因。
