CRISPR-Cas systems in Fusobacterium: An untapped genetic frontier

ABSTRACT Fusobacterium nucleatum has recently received significant attention for its strong connection with the acceleration and gravity of multiple cancers (e.g., colorectal, pancreatic, esophageal). However, our understanding of the molecular mechanisms that drive infection by this ‘oncomicrobe’ have been hindered by a lack of universal genetic tools. Herein we report a global bioinformatic identification and characterization of multiple Fusobacterium CRISPR-Cas adaptive immune systems including Cas13c, and detailed report of the proteins, spacer/repeat loci, trans- activating CRISPR RNA (tracrRNA), and CRISPR RNA (cRNA) from a Type II-A CRISPR-Cas9 system. Since most Fusobacterium are currently genetically intractable, this CRISPR-Cas bioinformatic roadmap could be used to build new genome editing and transcriptional tuning tools to characterize an increasingly important genus of human opportunistic-pathogens connected to the onset, progression, and severity of cancer.