PDF(Pubmed)
Abstract：
Ewing sarcoma (EwS) is a cancer that arises in the bones and soft tissues, typically driven by the Ewing\'s sarcoma breakpoint region 1-Friend leukemia virus integration 1 (EWS-FLI) oncogene. Implementation of genetically modified animal models of EwS has proved difficult largely owing to EWS-FLI\'s high toxicity. The EWS-FLI1FS frameshift variant that circumvents toxicity but is still able to perform key oncogenic functions provided the first study model in Drosophila. However, the quest for Drosophila lines expressing full-length, unmodified EWS-FLI remained open. Here, we show that EWS-FLI1FS\'s lower toxicity is owed to reduced protein levels caused by its frameshifted C-terminal peptide, and report new strategies through which we have generated Drosophila lines that express full-length, unmodified EWS-FLI. Using these lines, we have found that the upregulation of transcription from GGAA-microsatellites (GGAAμSats) presents a positive linear correlation within a wide range of EWS-FLI protein concentrations. In contrast, rather counterintuitively, GGAAμSats-independent transcriptomic dysregulation presents relatively minor differences across the same range, suggesting that GGAAμSat-dependent and -independent transcriptional upregulation present different kinetics of response with regards to changing EWS-FLI protein concentration. Our results underpin the functional relevance of varying EWS-FLI expression levels and provide experimental tools to investigate, in Drosophila, the effect of the EWS-FLI \'high\' and \'low\' states that have been reported and are suspected to be important for EwS in humans.
摘要：
尤因肉瘤（EwS）是一种发生在骨骼和软组织中的癌症，通常由尤文肉瘤断点区1-Friend白血病病毒整合1（EWS-FLI）癌基因驱动。由于EWS-FLI的高毒性，EwS的转基因动物模型的实施已被证明是困难的。EWS-FLI1FS移码变体可以避免毒性，但仍然能够执行关键的致癌功能，这是果蝇的第一个研究模型。然而,寻找表达全长的果蝇系，未经修改的EWS-FLI仍然开放。这里,我们表明EWS-FLI1FS的低毒性是由于其码变的C-末端肽引起的蛋白质水平降低，并报告新的策略，通过这些策略我们产生了表达全长的果蝇系，未修改的EWS-FLI。使用这些线，我们发现，在广泛的EWS-FLI蛋白浓度范围内，GGAA微卫星（GGAAμSats）的转录上调呈正线性相关。相比之下,相当违反直觉，GGAAμSats非依赖性转录组失调在同一范围内表现出相对较小的差异，表明GGAAμSat依赖性和非依赖性转录上调在改变EWS-FLI蛋白浓度方面表现出不同的反应动力学。我们的结果支持不同的EWS-FLI表达水平的功能相关性，并提供实验工具来研究，在果蝇中，EWS-FLI\'高\'和\'低\'状态的影响已被报道，并被怀疑对人类的EwS很重要。
