24 May 2010

The synthetic genome works!

The culmination of the project, on which the specialists of the Craig Venter Institute (Maryland) have been working for 15 years, was the creation of the first cells whose vital activity is controlled by a fully synthetic genome.

Using a method developed in 2008, the authors, working under the guidance of the famous Craig Venter, synthesized the genome of a tiny bacterium Mycoplasma mycoides, containing just over a million pairs of nucleotide bases. After that, using a method perfected in experiments using conventional chromosomes, they transplanted a synthetic genome into related Mycoplasma capricolum bacteria.

After the introduction of the synthetic genome, the recipient cells immediately began to follow the instructions encoded in the transplanted genome. The cells completely switched to the synthesis of Mycoplasma mycoides proteins and after several consecutive divisions completely lost the signs of Mycoplasma capricolum. The results of this outstanding work were published on May 20 in the preliminary on-line version of the journal Science in the article "Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome".

The synthetic genome contains a marker gene encoding a blue-colored compound that stains cell colonies (top), whereas wild-type Mycoplasma mycoides colonies are colorless (bottom).

Moreover, in order to ensure that the synthetic genome differs from the natural version, the researchers encoded a kind of "watermarks" into its sequence. They developed a cipher to encode the English alphabet, punctuation marks and numbers using the DNA language. After that, they "entered" their names, several quotes and the address of the site into the genome, which those who wish will be able to visit, provided that the inscription is successfully deciphered. The key to the cipher is also encoded in the DNA sequence.

The work done by the authors proves the possibility of creating synthetic forms of life, since, in addition to hidden inscriptions and the absence of several genes (to reduce the pathogenicity of bacteria), the synthetic genome as a whole repeats the natural one. Venter hopes that in the future, the technology of creating synthetic genomes will allow the development and reproduction of completely new organisms designed to solve a wide range of practical tasks.

Currently, Venter and his colleagues are working together with Novartis and the US National Institutes of Health to synthesize cassettes (clusters of genes suitable for embedding into a synthetic genome) for each of the known variants of the influenza virus. The aim of this work is to rationalize the production process of influenza vaccines through the introduction of a production system that allows you to quickly combine DNA fragments corresponding to the genes of a specific strain of the virus. The resulting synthetic genome will make it possible to create cells that produce the protein product necessary for the production of an effective vaccine at a high speed.

The researchers are also collaborating with ExxonMobil. The goal of this collaboration is to transform algae cells into living factories that efficiently convert carbon dioxide into hydrocarbons suitable for fuel production. According to Venter, to date, scientists have not been able to find a single living organism capable of carrying out this process with an efficiency that ensures the economic profitability of production.

Other possible activities are the creation of microorganisms for water purification, as well as the synthesis of chemical compounds or components of food products. Venter predicts that in ten years all cells used in production processes will be of synthetic origin. To do this, the researchers plan to create a universal cell capable of accepting any donor genome. The process of genome transplantation turned out to be the most technically difficult aspect of creating an artificial cell, which will be avoided by creating such a universal recipient cell.

Venter also hopes that, in addition to practical applications, artificial cells will help in studying the basics of the functioning of living organisms. Perhaps with their help it will be possible to accurately determine the functions of each component of the bacterial cell.

In general, the creation of an artificial cell will mark the end of an era in which cells and DNA had to be physically moved from one place to another, and the beginning of a new era in which biology is transformed into information science. This means that the genome of an organism can be synthesized, for example, in San Francisco, send the sequence by email and reproduce the organism, for example, in Maryland. That is, possession of information will be enough to reconstruct the body and "revive" it anywhere in the world.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of TechnologyReview: Synthetic Genome Reboots Cell. 


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