Expanding the Zebrafish Genetic Code through Site-Specific Introduction of Azido-lysine, Bicyclononyne-lysine, and Diazirine-lysine

Site-specific incorporation of un-natural amino acids (UNAA) is a powerful approach to engineer and understand protein function [1-4]. Site-specific incorporation of UNAAs is achieved through repurposing the amber codon (UAG) as a sense codon for the UNAA, a tRNA CUA that base pairs with an UAG codon in the mRNA and an orthogonal amino-acyl tRNA synthetase (aaRS) that charges the tRNA CUA with the UNAA [5, 6]. Here, we report expansion of the zebrafish genetic code to incorporate the UNAAs, Azido-lysine (AzK), bicyclononyne-lysine (BCNK), and Diazirine-lysine (AbK) into green fluorescent protein (GFP) and Glutathione-S-transferase (GST). We also present proteomic evidence for UNAA incorporation into GFP. Our work sets the stage for the use of UNAA mutagenesis to investigate and engineer protein function in zebrafish.