Tet-inducible “gePSI” protein reversibly regulates eukaryotic ribosomal protein synthesis in a cell-type specific manner allowing to impose and release protein synthesis inhibition in a select subset of cells in mixtures

Scientists from the Max-Planck Institute for Brain Research in Frankfurt/Main designed two separately expressed polypeptide chains forming together a genetically encoded Protein Synthesis Inhibitor (gePSI) (1). gePSI allows for a cell-type selective, tetracycline inducible and hence reversible inhibition of protein synthesis.
The basis for the gePSI system is a class of bacterial and plant toxins from the Shiga and Ricin families that are also known as ribosome inactivating proteins (RIPs). These highly potent proteins trigger a complete shutdown of protein synthesis by depurinating a specific adenine on the ribosomal 28S-rRNA. The scientists harnessed the toxicity, that might be exhibited by leaky expression already, by splitting the protein in two domains, each domain being inactive in isolation. The gePSI plasmid-based system provides expression of the Tet-dependent transcriptional activator targeting to the gePSI expression cassettes under a cell-type specific promoter allowing for the intended spatial and temporal control of gePSI formation and function.
The system was successfully tested in neurons and was shown to interfere effectively with protein synthesis in a cell-type-specific manner. Neighboring cells in direct physical contact with gePSI-expressing cells showed no change in protein synthesis. The expression of gePSI in such neurons was time-controlled, protein synthesis inhibition was achieved after 2-4 hours and removal of the gePSI-expression-inducing agent (tetracycline) allowed functional recovery of protein synthesis.
In summary, gePSI is a highly effective tool to impact on protein synthesis in a subset of cells in a complex mixture or tissue (e.g. cell cultures, organoids, tissue- or animal models) allowing for disease modelling (e.g.: Parkinson or else) and/or drug screenings that rely on or need interrupted protein synthesis in selected cell-types in a mixture.

(1) Heumüller M. et al., Nature Methods 2019, doi: 10.1038/s41592-019-0468-x

A PCT application is pending.