Simultaneous synthesis of all 21 types of tRNA in vitro

Collaborative research by the University of Tokyo and RIKEN Center for Biosystems Dynamics Research has led to the development of a new method for simultaneously synthesizing all transfer RNA (tRNA) required for protein synthesis in a reconstituted translation system in vitro.

Currently, humans rely on living organisms (bacteria, yeast, plants, and animals) for the production of pharmaceuticals and food. However, living organisms are susceptible to environmental changes, breeding improvements require time, and achieving precise control is difficult. If we could build artificial systems possessing the ability to regenerate themselves, like living organisms, we could realize stable production systems that are precisely designed and controllable, like industrial products, and are unaffected by environmental factors.

Developing self-regenerating artificial molecular systems, that is, systems that create themselves, requires synthesizing the protein synthesis system itself in a test tube using that very system. Ichihashi and his research group have already achieved world-first success in the sustained reproduction of all 20 enzymes (aminoacyl-tRNA synthetases) essential for the protein synthesis system. However, the protein synthesis mechanism requires at least 21 types of tRNA, which presents a significant technical barrier. Therefore, in this study, they developed a novel method (the tRNA array method) to synthesize all 21 types of tRNA simultaneously within the tRNA-omitted protein synthesis system.

In this method, all tRNAs corresponding to the 20 amino acids are encoded as genes within a single DNA (plasmid). From this, the tRNAs are transcribed collectively and then separated into individual tRNAs using the HDV ribozyme and RNase P. They can then be used directly to translate any desired gene.

This research represents a significant step toward realizing an artificial molecular system with self-reproducing capabilities. By adding further necessary genes to this system, it is anticipated that this will lead to the development of material production platforms with higher design flexibility and controllability than those of biological systems in the future. Furthermore, this tRNA synthesis method is expected to greatly simplify genetic code modification, contributing to the development of artificial proteins and peptides that incorporate non-natural amino acids.

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Journal article:

Ryota Miyachi, Keiko Masuda, Yoshihiro Shimizu, Norikazu Ichihashi, “Simultaneous in vitro expression of minimal 21 transfer RNAs by tRNA array method”, Nature communications, DOI: 10.1038/s41467-025-62588-y, https://doi.org/10.1038/s41467-025-62588-y

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