Structural Basis for Virulence Activation of Francisella tularensis.

ABSTRACT: The bacterium Francisella tularensis (Ft) is one of the most infectious agents known. Ft virulence is controlled by a unique combination of transcription regulators: the MglA-SspA heterodimer, PigR, and the stress signal, ppGpp. MglA-SspA assembles with the σ⁷⁰-associated RNAP holoenzyme (RNAPσ⁷⁰), forming a virulence-specialized polymerase. These factors activate Francisella pathogenicity island (FPI) gene expression, which is required for virulence, but the mechanism is unknown. Here we report FtRNAPσ⁷⁰-promoter-DNA, FtRNAPσ⁷⁰-(MglA-SspA)-promoter DNA, and FtRNAPσ⁷⁰-(MglA-SspA)-ppGpp-PigR-promoter DNA cryo-EM structures. Structural and genetic analyses show MglA-SspA facilitates σ⁷⁰ binding to DNA to regulate virulence and

SUBMITTER: Travis BA 

PROVIDER: S-EPMC7959165 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature