RNA landscape of the emerging cancer-bug Fusobacterium nucleatum

Fusobacterium nucleatum, long known as a constituent of the oral microflora, has recently garnered much attention for its newly discovered prevalence in colorectal and breast cancer tissue. The growing interest in this emerging cancer-associated bacterium sharply contrasts with a paucity of knowledge about its basic gene expression features and physiological responses. Post-transcriptional networks are also unknown, for fusobacteria lack all established small RNA-associated proteins. Here, we present high-resolution global RNA maps for two clinically relevant F. nucleatum subspecies for different growth conditions, and use these to uncover fundamental aspects of fusobacterial gene expression architecture and a previously unknown suite of noncoding RNAs. Developing a new vector for functional analysis of fusobacterial genes, we identify a conserved oxygen-induced small RNA as a post-transcriptional repressor of major porin FomA. Our findings provide a crucial step towards delineating the regulatory networks enabling F. nucleatum to colonize different compartments of the human body. Samples of different growth stages were taken for RNA extraction. Isolated RNA was used for cDNA library generation following the dRNA-seq protocol.