外源DNA在哺乳动物细胞中不依赖于启动子的转录和剪接现象

摘要

Introduction of exogenous double stranded DNA into mammalian cells will undergo restructuring,rearrangement and other complex molecular and biochemical reaction. Few DNA molecules will randomly integrate into the host genome,namely the occurrence of horizontal gene transfer. However,it is unclear whether these exogenous DNA molecules can be recognized by cell machine and triggers the transcription in the circumstance of containing no special promoter. During the construction of circle RNA(circRNA)expression system, we discovered that promoter-independent transcription of exogenous DNA occurred,also RNA splicing was in accord with"GU-AG"in transcripts,and subsequently abnormal spliced molecules similar to the circRNA formed. Further studies showed that the promoter-independent transcription and splicing of exogenous DNA in mammalian cells were conservative. Conclusively,this work revealed a new destiny approach of exogenous DNA in the mammalian cells,which is of significance and applicability in studying the effects of exogenous DNA on host cells.%外源性导入哺乳动物细胞的双链DNA会经历重组、重排及其他复杂的分子生化反应.极少数DNA分子会随机整合到宿主基因组,即发生水平基因转移.然而,目前还不清楚这些外源性DNA分子在不含有特殊启动子的情况下是否能被细胞的转录机器识别并起始转录.在构建环状RNA(circRNA)表达体系的过程中,发现了外源性DNA分子能经历不依赖启动子的转录,而且转录本会发生符合"GU-AG"法则的RNA剪接进而产生类似于环状RNA的异常剪接分子.进一步研究表明,外源DNA在哺乳动物细胞中不依赖于启动子的转录和剪接现象是保守的.揭示了外源DNA在哺乳动物细胞中的一个新的命运途径,该发现对研究外源性DNA对宿主细胞的影响具有重要意义及应用价值.