Self-targeting spacers reveal new functions of CRISPR systems

Abstract

The CRISPR systems enable bacteria and archaea to defend from bacteriophages or mobile genetic elements by inserting portions of the DNA of these elements into its own genome in sequences known as spacers that will later trigger the complementarity-based degradation of invading sequences. The presence of self-targeting spacers is widespread in prokaryotes; however, its functional role is still unclear. In this study, we analyzed self-targeting spacers of CRISPR systems and found a high presence of membrane proteins, aminoacyl-tRNA synthetases and ATP-binding proteins. This is a novel report that supports other research linking CRISPR systems to membrane proteins and could explain the reported relationships between antibiotic resistance and presence of CRISPR systems.