Virulence Regulation in Borrelia burgdorferi.

Borrelia burgdorferi, the causative agent of Lyme disease, is the most common vector-borne disease in the United States. Compared with other bacterial pathogens, B. burgdorferi has many unique features. For instance, its highly segmented genome was predicted to encode very few proteins directly dedicated to gene expression regulation. Yet, the spirochete continuously reprograms its transcriptome and proteome to promote survival and pathogenesis as spirochetes traverse the enzootic lifecycle between ticks and mammals. Signal sensing systems, a unique alternative sigma factor cascade, and multi-functional regulators work in concert to coordinate virulence gene expression under different tick and mammal environments. In this review, we have summarized recent advances in gene regulation in B. burgdorferi.