CRISPR reengineered to block other proteins

Gene editing tool CRISPR has been repurposed as a gene blocker in order to study antimicrobial resistance.

CRISPR is a gene-editing tool that targets DNA of interest and changes the nucleotide sequence. Now a team from the US has engineered a form of CRISPR – Mobile CRISPRi – to sit on the DNA and block the gene.

The system reduces the production of protein from targeted genes, allowing researchers to identify how antibiotics inhibit the growth of pathogens and how to improve them.

Jason Peters, UW-Madison professor and developer of the system, said: “You can now do studies on how antibiotics work directly in these pathogens. That could give us a better clue about how these drugs work in the said organisms and potentially what we can do to make them better.”

Using conjugation – a form of bacterial sex – Peters’ team transferred Mobile-CRISPRi from common lab strains to pathogens including Pseudomonas, Salmonella, Staphylococcus and Listeria, as well as Vibrio casei, a bacterium found on the rind of a French cheese.

The team showed that if they decreased the protein targeted by an antibiotic, bacteria became more sensitive to lower levels of the drug. Thousands of genes at a time can be screened as potential antibiotic targets this way.

Disease-causing pathogens developing antibiotic resistance are estimated to endanger millions of lives and cost over $2 billion a year in the US. The WHO has said: “A post-antibiotic era – in which common infections and minor injuries can kill – far from being an apocalyptic fantasy, is instead a very real possibility for the 21st Century.”

Professor Peters worked with collaborators at the University of California. The researchers published their findings in the journal Nature Microbiology.