A new mechanism of CRISPR-Cas-targeted plasmid persistence in subpopulations of bacterial cells
CRISPR-Cas systems are widely recognized as a genome editing tool. In nature, these systems play the role of bacterial adaptive immunity against bacteriophages and other mobile genetic elements. It is generally believed that mutations are responsible for overcoming such defenses. In a study led by Konstantin Severinov involving several groups from Russia, the United States and Chile, it was found that even with a fully functional CRISPR-Cas and an unmutated target sequence, the plasmid can persist for many generations in a small subpopulation of E. coli cells. A model system using fluorescent proteins made it possible to trace the activity of the CRISPR-Cas system at the level of single living bacterial cells. The work was published in the Proceedings of the National Academy of Sciences of USA.
april 22, 2022