BioProject

Lyme disease spirochetes must induce RpoS-dependent genes during tick feeding to prepare for host infection. More...

Lyme disease spirochetes must induce RpoS-dependent genes during tick feeding to prepare for host infection. Previous work in our lab identified bbd18 as a negative regulator of RpoS, but inactivation of bbd18 in wild-type spirochetes was never achieved. In the current study we generated an inducible bbd18 gene at the endogenous plasmid locus and demonstrated the essential nature of BBD18 for viability of wild-type spirochetes in vitro and at a unique point in vivo. Transcriptomic analyses demonstrated global induction of RpoS and RpoS-dependent genes following BBD18 depletion, culminating in spirochete lysis. Plasmid prophage genes were also induced and phage particles were detected in lysed culture supernatants, suggesting that RpoS regulates phage lysis-lysogeny decisions. The absolute requirement for BBD18 persisted following displacement of the entire set of cp32 plasmid prophages but could be circumvented by deletion of rpoS. This is the first report of a mechanistic  link between endogenous transducing prophages and the RpoS-dependent adaptive response of the Lyme disease spirochete. Overall design: Determine differential expression in inducible bbd18 and rpoS deletion strains of Borrelia burgdorferi Less...