Metabolic labelling of DNA in cells by means of the “photoclick” reaction triggered by visible light

Abstract

Two pyrene-tetrazole conjugates were synthesized as photoreactive chromophores that allow for the first time the combination of metabolic labelling of DNA in cells and subsequent bioorthogonal “photoclick” modification triggered by visible light.

Cyclopropenes as Chemical Reporters for Dual Bioorthogonal and Orthogonal Metabolic Labeling of DNA

“…The subsequent photoclick labeling was attempted with the pyrene‐tetrazole conjugate 13 . This dye can be photoactivated by visible light (405/450 nm LEDs), and the subsequent reaction of the nitrilimine is fluorogenic [3c] . The postsynthetic DNA labeling attempts, however, were not successful, neither with tetrazole 13 nor with 9 , likely due to the insolubility of the oligonucleotide samples in MeCN.…”

“…The postsynthetic DNA labeling attempts, however, were not successful, neither with tetrazole 13 nor with 9 , likely due to the insolubility of the oligonucleotide samples in MeCN. We know from our photoclick experiments in vitro and in cells that this chemistry requires substantial amounts of organic solvent, the most suitable is MeCN [3c] . Although this is an experiment with a negative outcome, it is an important result because it helped us to adjust the protocol for the dual metabolic labeling in a cellular environment, as described below.…”

Cellular Metabolic Labeling of Nucleic Acids and Its Applications

“…More recently, the Wagenknecht group came up with new strategy by combining VdU with tetrazoles involved "photoclick" reaction [14] to enable the labeling with spatiotemporal resolution. [15] Zhang et al demonstrated efficient and fluorogenic live cell labeling of DNA using a watersoluble tetrazole, activated by irradiation with 350 nm light. By utilizing VdU as a building block as well.…”

“…This strategy enables the live‐cell dynamic imaging of nucleic acids and provides a mix‐and‐measure fluorogenic assay for DNA replication. More recently, the Wagenknecht group came up with new strategy by combining VdU with tetrazoles involved “photoclick” reaction [14] to enable the labeling with spatiotemporal resolution [15] . Zhang et al.…”

Out of the Dark, into the Light: Metabolic Fluorescent Labeling of Nucleic Acids

“…A most recent example was presented by Rieger et al, who metabolically incorporated 5vinyl-2'-deoxyuridine (VdU) into HeLa cells. [36] After fixation and denaturation, photoirradiation with a 450 nm LED in the presence of a pyrene-substituted tetrazole allowed the visualization of the genomic DNA. Further, upon conversion of the tetrazole moiety in the photoclick reaction, a change in the fluorescence color and fluorogenicity could be observed.…”