A microdroplet instead of a cell
The first artificial genomic DNA has been created
Japanese biologists have created the first artificial genomic DNA that can reproduce and develop outside the cell. Scientists were able to start the process of gene expression and extracellular replication in DNA created in a cell-free system of nucleic acids and proteins. The results of the study are published in the journal ACS Synthetic Biology (Okauchi & Norikazu, Continuous Cell-Free Replication and Evolution of Artificial Genomic DNA in a Compartmentalized Gene Expression System).
The ability to reproduce and develop is one of the defining characteristics of living organisms. So far, it has not been possible to create artificial materials with such characteristics. In order for an artificial molecular system that can reproduce and develop to work, the genetic information encoded in DNA must be translated into RNA, protein expression is started, and the DNA replication cycle with these proteins must be maintained in the system for a long time. The main difficulty lies in the fact that the genes necessary for DNA replication must simultaneously perform their expression functions.
To get around this problem, scientists from The University of Tokyo, led by Professor Norikazu Ichihashi, instead of a 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 authors suggested that these two proteins will function well at low concentrations and will be able to be expressed in sufficient quantities even in existing cell-free translation systems.
They created such a cell-free transcription-translation system in which they managed to translate genes into proteins and replicate the original ring DNA using ring DNA carrying two genes necessary for replication. Moreover, they have successfully improved the original DNA, increasing the efficiency of its replication tenfold. The DNA replication cycle started by scientists lasted for 60 days.
The researchers note that by adding the genes necessary for transcription and translation to the artificial DNA they have developed, it is possible to create artificial cells that can grow autonomously, feeding on low-molecular compounds such as amino acids and nucleotides.
In the future, such cells can be used for the production of medicines and food. Now, for this purpose, live microorganisms are included in the technology. If they are replaced with artificial programmable cells, the processes will become more stable and manageable, the authors believe.
Portal "Eternal youth" http://vechnayamolodost.ru