The ability of the CRISPR / Cas system to store information helped make a sensor out of bacteria, capable of recording monitoring data into its own DNA.
The use of the CRISPR / Cas gene modification system helped to "supplement" bacterial cells with a mechanism for recording the state of the environment. This will make them live sensors that monitor the state of ecosystems and humans. Harris Wang and his colleagues at Columbia University in New York talked about their new work in an article published in Science.
Opened only at the turn of the XXI century. The CRISPR / Cas system serves bacteria as an analogue of our acquired immunity: the library of CRISPR DNA regions accumulates information about viruses that the cell has encountered, and Cas proteins work with it, quickly recognizing a new infection. The use of elements of this system has opened up completely new prospects for the genetic modification of organisms and has provided it with a particularly rapid development in recent years.
However, if GM engineers use the ability of CRISPR / Cas to recognize fragments of DNA complementary to the RNA template that scientists need and cut them exactly in the right place, this time they were interested in the "library" functions of the system. “CRISPR / Cas is a natural, biological memory device,” says Harris Wang. "From an engineering point of view, it is remarkably structured as it has already gone through an evolution that has honed its ability to store information."
Scientists have modified bacteria to respond to changes in some environmental factor - for example, the content of fructose or copper in it - by synthesizing short fragments of DNA plasmids. Also, the CRISPR / Cas system was modified so that the appearance of a large number of such plasmids was recorded in the CRISPR library. If, for example, copper was not enough, then the cell synthesized other plasmids, which were “stored” in CRISPR instead of “signal” ones.
"This approach provided stable recording over many days and accurate reconstruction of metrics and time by sequencing the CRISPR sequences," the scientists write in the article.
In the next phase, Harris Wang and his colleagues plan to test such a system to monitor biomarkers of bowel disease for at least a few days. "If this bacterium is swallowed by a patient, then it will be able to record all the changes that it encounters, passing through the entire digestive tract," says the scientist, "revealing previously unseen, inaccessible data."
Sergey Vasiliev
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