德国柏林洪堡大学的Oliver Seitz小组取得一项新突破。他们的最新研究开发了用于活细胞的肽核酸标签，实现膜蛋白的可擦除荧光成像。 该研究于2020年发表于《自然—化学》杂志。

课题组报告了一个共价标记反应，可以引入生物稳定的肽核酸（PNA)。反应在几分钟之内进行，且对于一个2kDa卷曲螺旋肽标签具有特异性。一旦安装完毕，PNA标签作为一个通用的“登陆平台”，通过核酸杂交实现荧光染料的“招募”。研究人员通过募集不同的荧光团、组装多个荧光团以提高亮度和通过toehold介导的链置换实现可逆标记来证明这种方法的多功能性。

此外，该课题组研究人员表明，标签可以使用两种不同的卷曲螺旋体系，在表皮生长因子受体和内皮素B型受体上实现，且在HEK293和CHO细胞内都可行。课题组人员应用该方法来监测CHO细胞上表皮生长因子受体的内在化。

据了解，DNA纳米技术是一个新兴领域，为细胞表面蛋白的操控和成像提供了非常有趣的机遇。取得进展的关键是在活细胞中建立核酸-蛋白质连接的能力。

附：英文原文

Title: Live cell PNA labelling enables erasable fluorescence imaging of membrane proteins

Author: Georgina C. Gavins, Katharina Grger, Michael D. Bartoschek, Philipp Wolf, Annette G. Beck-Sickinger, Sebastian Bultmann, Oliver Seitz

Issue&Volume: 2020-12-07

Abstract: DNA nanotechnology is an emerging field that promises fascinating opportunities for the manipulation and imaging of proteins on a cell surface. The key to progress is the ability to create a nucleic acid–protein junction in the context of living cells. Here we report a covalent labelling reaction that installs a biostable peptide nucleic acid (PNA) tag. The reaction proceeds within minutes and is specific for proteins carrying a 2kDa coiled-coil peptide tag. Once installed, the PNA label serves as a generic landing platform that enables the recruitment of fluorescent dyes via nucleic acid hybridization. We demonstrate the versatility of this approach by recruiting different fluorophores, assembling multiple fluorophores for increased brightness and achieving reversible labelling by way of toehold-mediated strand displacement. Additionally, we show that labelling can be carried out using two different coiled-coil systems, with epidermal growth factor receptor and endothelin receptor type B, on both HEK293 and CHO cells. Finally, we apply the method to monitor internalization of epidermal growth factor receptor on CHO cells.

DOI: 10.1038/s41557-020-00584-z

Source: https://www.nature.com/articles/s41557-020-00584-z