Labelling

Azide modified nucleotide closely resemble natural nucleotides and are the basis of chemoenzymatic mRNA labeling. Due to the small size of the azide this nucleotide is well accepted by T7 RNA polymerase and poly(A) polymerase and terminale deoxynucleotidyl transferase (Tdt) for enzymatic incorporation. This is highly beneficial, as labeling of mRNA with our approach is modular and not limited to enzymatic compatibility of bulky pre-labeled nucleotides. Moreover, only a very limited number of such pre-modified nucleotides, mainly dye-labeled ones, are commercially available. Internal and external studies successfully showed e.g. that the poly(A) polymerase adds specifically and sequence independently single azido terminator to the 3’-end of RNA. The main advantage: Any mRNA can be site-specifically labeled without special requirements or altered production protocols at the 3’-end.