A new "safety collar" for GMOs
Bioengineers have created a new type of "Kill Switch" switch
for genetically modified organisms
DailyTechInfo based on Gizmodo materials: Genetic Engineers Are Building a Biological Kill SwitchGenetically modified creatures escaping from the walls of some laboratory, or specially bred bacteria seeping through the soil into the surrounding world as a result of leakage, are a fairly common scenario for many science fiction works.
But soon, as genetic technologies develop, such scenarios may become a real threat to people and to all living things on the globe. That is why genetic engineers invent biological "switches", gene-encoded triggers of programmed suicide for genetically modified organisms (GMOs), which should be triggered when various unforeseen situations occur.
When we hear the term "GMO", the first thing that comes to mind is agricultural plants that are adapted to grow in unsuitable conditions for them or have received modifications to increase their yield. However, there are already several examples of the use of genetically modified organisms, for example, mosquitoes, which have been used to fight malaria and Dengue fever, and many bacteria of various kinds, the leakage of which into nature can have unpleasant consequences.
The "Kill Switch" switch is basically a part of the genetic code that is fatal to the organism, which is activated when several necessary conditions, such as temperature, humidity, illumination, etc., coincide. The most common strategy for activating switches is the dependence of modified organisms on some chemical compound that is supplied to them in the laboratory along with nutrients. As soon as such organisms leave the laboratory, this substance ceases to enter their cells, the corresponding switches are activated and the modified organisms die before they have time to multiply or mutate.
This method was used to create modified Aedes aegypti mosquitoes, which were intended to fight malaria. The company Oxitec, which dealt with these mosquitoes, "hooked" them on tetracycline, which is known as a common antibiotic. But in the case of mosquitoes, this drug played a completely different role – if GM mosquitoes had flown out of the "strict regime insectarium", without tetracycline they would have died soon.
Unfortunately, this method will not work with respect to all types of modified organisms, bacteria of some species are sufficiently tenacious in order to have time to transfer part of their modified genetic material to other normal bacteria living in the environment.
Last week, scientists announced the creation of a new type of "Kill Switch" switch that can not only kill a modified organism, but also erase its altered genes. This switch uses elements of CRISPR technology, a new technology of molecular biology that allows fairly accurate manipulation of the genocode and DNA. This technology uses special enzymes and proteins that allow you to cut the target DNA molecule with high accuracy.
While conducting their research, the scientists designed E. coli bacteria whose genes contained elements of CRISPR technology. These areas of the genetic code were activated in the presence of sugar – arabinose. As soon as the molecules of such sugar got inside the bacterial cell, the CRISPR mechanism was activated, destroying the DNA of the cell, which inevitably led to its death. The CRISPR system can be configured in such a way that modified organisms, when exposed to certain factors of the ordinary environment, will quickly die, and critical sections of their synthetic DNA will simply be erased. This will not only prevent modified organisms from entering the world around them, but also keep their genetic code secret, which is the intellectual property of the companies that developed them.
Despite the successes achieved, the technologies for creating genetic switches are still far from perfect, each of them is not yet able to provide guaranteed protection of the surrounding world from organisms that have "escaped" from laboratories. And given that the complexity of genetically modified organisms is increasing literally every day, people will soon need more sophisticated ways to protect themselves from these organisms.
(The article by B. J. Caliando & C. A. Voigt Targeted DNA degradation using a CRISPR device stably carried in the host genome is published in the journal Nature Communications – VM).
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