tRNAslation · Deciphering the role of RNA modifications during ribosomal decoding and protein synthesis

All living cells employ messenger RNAs (mRNA), transfer RNAs (tRNA) and ribosomal RNAs (rRNA) to decode genomic information and synthesize the correct set of proteins at the right sub-cellular localization and at the right time. The attachment of specific chemical groups to individual RNA bases attributes novel chemical properties and strongly influences their functionality. In particular, modifications of the tRNA anticodon and critical regions of rRNAs are primed to influence the translation of individual mRNAs and tune the decoding behavior during ribosomal translation elongation. Individual ribosomes, mRNAs and tRNAs are dynamically decorated with different combinations of RNA modifications depending on the cell type, cellular compartment, metabolic state and environmental conditions. This additional layer of complexity creates specialized translational units and vastly expands the regulatory potential of the strictly conserved and almost invariant core translation machinery. Despite their key role in translation, most modification cascades and the functional interplay of the resulting RNA modifications during ribosomal decoding remain elusive. In the proposed project, we aim (i) to structurally characterize key RNA modification complexes, (ii) to create sets of fully modified RNAs in vitro, (iii) to understand the role of individual rRNA and tRNA modifications during translation elongation and (iv) to provide mechanistic insights into the unfortunate link between patient derived mutations of the underlying pathways and the onset of severe human diseases. In summary, we will extend the recently arising concept of specialized ribosomes by adding unique RNA modifications into the overall scheme. This project will provide deep molecular insights into fundamental processes, that are clinically relevant and which regulate, shape and orchestrate the cellular protein landscapes in all known organisms.