EbfC (YbaB) Is a New Type of Bacterial Nucleoid-Associated Protein and a Global Regulator of Gene Expression in the Lyme Disease Spirochete

Nearly every known species ofEubacteria encodes a homolog of theBorrelia burgdorferi EbfC DNA-binding protein. We now demonstrate that fluorescently tagged EbfC associates withB. burgdorferi nucleoidsin vivo and that chromatin immunoprecipitation (ChIP) of wild-type EbfC showed it to bindin vivo to sites throughout the genome, two hallmarks of nucleoid-associated proteins. Comparative RNA sequencing (RNA-Seq) of a mutantB. burgdorferi strain that overexpresses EbfC indicated that approximately 4.5% of borrelial genes are significantly impacted by EbfC. TheebfC gene was highly expressed in rapidly growing bacteria, butebfC mRNA was undetectable in stationary phase. Combined with previous data showing that EbfC induces bends in DNA, these results demonstrate that EbfC is a nucleoid-associated protein and lead to the hypothesis thatB. burgdorferi utilizes cellular fluctuations in EbfC levels to globally control transcription of numerous genes. The ubiquity of EbfC proteins inEubacteria suggests that these results apply to a wide range of pathogens and other bacteria.