Ultraviolet radiation (UVR) is a known genotoxic agent. Although its effects on DNA have been well-documented, its impact on RNA and RNA modifications is less studied. By using Escherichia coli tRNA (tRNA) as a model system, we identify the UVA (370 nm) susceptible chemical groups and bonds in a large variety of modified nucleosides. We use liquid chromatography tandem mass spectrometry to identify specific nucleoside photoproducts under in vitro and in vivo conditions, which were then verified by employing stable-isotope labeled tRNAs. These studies suggest that the -amino or -oxy groups of modified nucleosides, in addition to sulfur, are labile in the oxidative environment generated by UVA exposure. Further, these studies document a range of RNA photoproducts and post-transcriptional modifications that arise because of UVR-induced cellular stress.

中文翻译：

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紫外线辐射对RNA中核苷修饰的影响

紫外线辐射（UVR）是已知的遗传毒性剂。尽管其对DNA的作用已得到充分证明，但对RNA和RNA修饰的影响却鲜有研究。通过使用大肠杆菌tRNA（tRNA）作为模型系统，我们鉴定了UVA（370 nm）敏感的化学基团和键合在多种修饰的核苷中。我们使用液相色谱串联质谱法在体外和体内鉴定特定的核苷光产物条件，然后通过使用稳定同位素标记的tRNA进行验证。这些研究表明，除了硫以外，修饰的核苷的-氨基或-氧基在由UVA暴露产生的氧化环境中也是不稳定的。此外，这些研究记录了由于UVR诱导的细胞应激而引起的一系列RNA光产物和转录后修饰。