AbstractThe metabolic labeling of nucleic acids in living cells is highly desirable to track the dynamics of nucleic acid metabolism in real‐time and has the potential to provide novel insights into cellular biology as well as pathogen‐host interactions. Catalyst‐free inverse electron demand Diels–Alder reactions (iEDDA) with nucleosides carrying highly reactive moieties such as axial 2‐trans‐cyclooctene (2TCOa) would be an ideal tool to allow intracellular labeling of DNA. However, cellular kinase phosphorylation of the modified nucleosides is needed after cellular uptake as triphosphates are not membrane permeable. Unfortunately, the narrow substrate window of most endogenous kinases limits the use of highly reactive moieties. Here, we apply our TriPPPro (triphosphate pronucleotide) approach to directly deliver a highly reactive 2TCOa‐modified 2′‐deoxycytidine triphosphate reporter into living cells. We show that this nucleoside triphosphate is metabolically incorporated into de novo synthesized cellular and viral DNA and can be labeled with highly reactive and cell‐permeable fluorescent dye‐tetrazine conjugates via iEDDA to visualize DNA in living cells directly. Thus, we present the first comprehensive method for live‐cell imaging of cellular and viral nucleic acids using a two‐step labeling approach.
摘要 对活细胞中的核酸进行代谢标记非常有助于实时跟踪核酸代谢的动态,并有可能为细胞
生物学以及病原体与宿主之间的相互作用提供新的见解。与携带高活性分子(如轴向 2-
反式环辛烯(2TCOa))的核苷进行的无催化剂反电子需求 Diels-Alder 反应(iE
DDA)是实现 DNA 细胞内标记的理想工具。然而,由于
三磷酸盐不具有膜渗透性,因此细胞摄取后需要细胞激酶对修饰的核苷进行
磷酸化。遗憾的是,大多数内源性激酶的底物窗口狭窄,限制了高活性分子的使用。在这里,我们采用 TriPPPro(
三磷酸代核苷酸)方法将高活性的 2TCOa 修饰的 2′-脱氧
胞苷三磷酸报告物直接输送到活细胞中。我们的研究表明,这种
三磷酸核苷可通过新陈代谢结合到新合成的细胞和病毒 DNA 中,并可通过 iE
DDA 用高活性和细胞渗透性荧光
染料-四嗪共轭物进行标记,从而直接观察活细胞中的 DNA。因此,我们首次提出了利用两步标记法对细胞和病毒核酸进行活细胞成像的综合方法。