[Seminar] "Making an artificial cell capable of Darwinian evolution and artificial cell techniques for evolutionary engineering"

Speaker: Prof. Norikazu Ichihashi, the Unviersity of Tokyo

Title: Making an artificial cell capable of Darwinian evolution and artificial cell techniques for evolutionary engineering

Abstract: 

Evolution is the central function of living things, which produced the present-day amazing living world. In this presentation, I talk about two topics. First is the construction of artificial cell-like system capable evolution. We construct an artificial cell-like system consists of an artificial genomic RNA and a cell-free translation system. As a cell-like structure, we used a water-droplets of few micrometer dispersed in an oil phase, in which the genomic RNA self-replicates through the translation of the encoded replication enzyme. When we incubated this system and periodically diluted with new droplets containing the cell-free translation system, the genomic RNA replicates with spontaneous mutations, and more replicable mutant dominated the population according to Darwinian principle. During the evolutionary process, we observed several biological phenomena, parasite appearance [1], evolutionary arms race, and endless evolution. We also found that this system can be extended by introducing another RNA that encodes a metabolic gene [2]. We believe that this evolvable artificial system can be a useful experimental model to understand the evolution of life. In the second part of my presentation, I talk about our new techniques for evolutionary engineering, by which we developed more active DNA polymerases and a less modified ribosome [3]. I also present our recent finding on the relationship between structural fluctuation of RNA and evolution. 

References

[1] Y. Bansho, T. Furubayashi, N. Ichihashi*, T. Yomo* (*co-correspoinding)

Host-parasite oscillation dynamics and evolution in a compartmentalized RNA replication system

Proc Natl Acad Sci U S A 113 (2016) 4045-4050.

[2] R. Mizuuchi, N. Ichihashi

Sustainable replication and coevolution of cooperative RNAs in an artificial cell-like system

Nat Ecol Evol 2 (2018) 1654-1660.

[3] Y. Murase, H. Nakanishi, G. Tsuji, T. Sunami, N. Ichihashi

In Vitro Evolution of Unmodified 16S rRNA for Simple Ribosome Reconstitution