Identification of proline to serine mistranslation in Drosophila melanogaster pupae

Transfer RNAs (tRNAs) are the adaptor molecules required for reading of the genetic code and the accurate production of proteins. tRNA variants can lead to genome-wide mistranslation, the misincorporation of amino acids not specified by the standard genetic code, into nascent proteins. While genome sequencing has identified putative mistranslating tRNA variants in human populations, little is known regarding how mistranslation affects multicellular organisms. Here, we create a Drosophila melanogaster model for mistranslation by integrating a serine tRNA variant that mistranslates serine for proline (tRNA(Ser)[UGG, G26A]) into the fly genome. Using mass spectrometry, we find that tRNA(Ser)[UGG, G26A] misincorporates serine for proline at a frequency of ~ 0.6% per codon. This model will enable studies into the synergistic effects of mistranslating tRNA variants and disease-causing alleles.