Ribosome profiling and mRNA seq demonstrate that insertion of common resistance cassettes in yeast drives aberrant transcription

Our study found that insertion of commonly used selection cassettes in yeast can drive aberrant transcription events and disrupt expression of neighboring genes. We performed ribosome profiling and mRNA-seq on yeast strains where ORFs had been replaced with common selection cassettes and observed aberrant transcripts. Aberrant transcripts positioned near adjacent genomic loci repressed protein synthesis of those genes by transcription interference (ablating normal length transcript production) coincident with translation of competitive uORFs on the long transcript which prevented translation of the main ORF seen by ribosome profiling.本研究发现，在酵母中插入常用筛选标记盒（selection cassettes）可诱发异常转录事件，并扰乱邻近基因的表达。我们对开放阅读框（Open Reading Frames，ORFs）被常见筛选标记盒替换的酵母菌株开展了核糖体谱分析（ribosome profiling）与mRNA-seq，观测到了异常转录本。定位于相邻基因组位点（genomic loci）附近的异常转录本可通过转录干扰（transcription interference，即消除正常长度转录本的生成）抑制对应基因的蛋白质合成；与此同时，长转录本上竞争性上游开放阅读框（upstream Open Reading Frames，uORFs）的翻译过程，会阻碍核糖体谱分析所检测到的主开放阅读框（main ORF）的翻译。