Genetically modified antibiotics

Scientists from the University of Wisconsin-Madison, in collaboration with colleagues from the University of California San Francisco, modified the well-known CRISPR technique in order to study the genetic targets of a number of antibiotics. The method used, CRISPRi, is a modification of the well-known method of genome editing, but it is not itself aimed at changing the structure of DNA. Instead, the CRISPRi complex simply "sits down" on DNA, blocking access to it by other proteins, thus reducing the expression level of the gene on which the complex "sat down". The result of this is a decrease in the amount of a certain protein in the cell.

In their work, the researchers used an even more complex modification of the technique: Mobile-CRISPRi, which allows scientists to screen the functioning of antibiotics on a wide range of pathogenic bacteria.

Many pathogenic bacteria are poorly studied and are uncultivated, which makes it difficult to work with them. The peculiarity of the technique in comparison with CRISPRi is the simplicity of transferring complexes from cells of "model" bacteria, such as E.coli, into cells of various pathogenic bacterial species by conjugation – one of the forms of bacterial sexual process. The use of such a system makes it possible to study genes not only on known model objects, but also on newly isolated samples from the environment that have no analogues in the form of culture.

For the first time this method was tested in the study of the Vibrio casei bacterium isolated from cheeses. The Mobile-CRISPRi technique was used to study the mechanisms by which bacteria colonize cheese and help it to ripen. The results obtained indicate that the method will also be effective in the study of any insufficiently studied bacteria, both pathogenic and beneficial to humans.

The data of the study of the effect of a number of bacterial genes on antibiotics have shown that when certain genes are blocked, bacteria become more sensitive to low doses of antibiotics, which indicates the presence of a relationship between antibiotic resistance and genes. These results may help scientists to establish exactly how antibiotics suppress the growth of pathogens, which will eventually allow the development of new antibiotics and improve existing ones.

The authors of the article offer a methodology to other scientists to work on their bacterial objects.

Article by Peters et al. Enabling genetic analysis of diverse bacteria with Mobile-CRISPRi is published in Nature Microbiology.

Anastasia Poznyak, portal "Eternal Youth" http://vechnayamolodost.ru / based on the materials of the University of Wisconsin-Madison: Gene-editing tool now being used to develop better antibiotics.