Japanese scientists have observed the replication and evolution of artificial genomic DNA outside the cell. This is reported by “Hi-Tech” with reference to a study in the journal ACS Synthetic Biology.
For the first time, Professor Norikazu Ichihashi and his colleagues at the University of Tokyo successfully induced the expression of DNA genes characteristic of all living things and evolution through continuous extracellular replication. To do this, they used only cell-free materials such as nucleic acids and proteins.
The ability to reproduce and develop is one of the defining characteristics of a living organism. Scientists have not been able to create artificial materials that would be capable of this. To develop an artificial molecular system that can multiply and develop, information (genes) encoded in DNA must be translated into RNA, proteins must be expressed, and the cycle of DNA replication with these proteins must continue for a long period in the system. To date, it is impossible to create a reaction system in which the genes necessary for DNA replication would be expressed while at this time these genes perform their main function.
To get around this problem, scientists from the University of Tokyo, led by Professor Norikazu Ichihashi, instead of the complex DNA replication mechanism used by living organisms, which requires a large number of genes, created an artificial replication system with only two genes – the DNA replication enzyme Phi29 and Cre recombinase. The researchers hypothesized that these proteins would function well at low concentrations and could be expressed in sufficient quantities even in existing cell-free translation systems.
They created such a cell-free transcription-translation system. In it, biologists were able to translate genes into proteins and replicate the original circular DNA using circular DNA, which carries two genes necessary for replication. In addition, they successfully improved the original DNA, increasing its replication efficiency by 10 times. As for the timing, the DNA replication cycle, which the scientists started, lasted for 60 days.
By adding the genes needed for transcription and translation to artificial genomic DNA in the future, it is possible to develop artificial cells that can grow autonomously by simply feeding them low molecular weight compounds such as amino acids and nucleotides. If such artificial cells can be created, it can be expected that the beneficial substances that are now created using living organisms (for example, for the development of drugs and the production of food) will become more stable and easier to control.
