Photocaged Hoechst Enables Subnuclear Visualization and Cell Selective Staining of DNA in vivo.

Carina A Lämmle,Martin Distel,Jenny Eichhorst,Hans‐Georg Kräusslich,Adam Varady,Thorsten G Müller,Johannes Broichhagen,Caterina Sturtzel,Michael Riepl,Anje Sporbert,Martin Lehmann,Bettina Mathes

doi:10.1002/cbic.202000465

Abstract

Selective targeting of DNA by means of fluorescent labeling has become a mainstay in the life sciences. While genetic engineering serves as a powerful technique and allows the visualization of nucleic acid by using DNA‐targeting fluorescent fusion proteins in a cell‐type‐ and subcellular‐specific manner, it relies on the introduction of foreign genes. On the other hand, DNA‐binding small fluorescent molecules can be used without genetic engineering, but they are not spatially restricted. Herein, we report a photocaged version of the DNA dye Hoechst33342 (pcHoechst), which can be uncaged by using UV to blue light for the selective staining of chromosomal DNA in subnuclear regions of live cells. Expanding its application to a vertebrate model organism, we demonstrate uncaging in epithelial cells and short‐term cell tracking in vivo in zebrafish. We envision pcHoechst as a valuable tool for targeting and interrogating DNA with precise spatiotemporal resolution in living cells and wild‐type organisms.

Highlights

Hoechst33342, which can be uncaged by using UV to blue light for the selective staining of chromosomal DNA in subnuclear regions of live cells
Expanding its application to a vertebrate model organism, we demonstrate uncaging in epithelial cells and short-term cell tracking in vivo in zebrafish
We explore the utility of pcHoechst in vivo, targeting and tracking nuclei of single cells in zebrafish embryos

Summary

Introduction

Hoechst33342 (pcHoechst), which can be uncaged by using UV to blue light for the selective staining of chromosomal DNA in subnuclear regions of live cells. We envision pcHoechst as a valuable tool for targeting and interrogating DNA with precise spatiotemporal resolution in living cells and wild-type organisms. The first 2,6-bis-benzimidazol derivatives were synthesized in 1974 as chemotherapeutic agents with their fluorescence increase upon binding to DNA already recognized in the initial publication.[15] While these compounds, widely known as “Hoechst”, did not hold promise for use in cancer therapy, they have become an invaluable tool to stain DNA in live cells. Hoechst typifies a chemical biology probe with remarkable characteristics, possessing good permeability, high affinity

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