Frank Carlo Gherardini, Ph.D.

Senior Investigator

Gene Regulation Section


Rocky Mountain Laboratories
Building 6, Room 6114
903 South 4th Street
Hamilton, MT 59840


Research Topics

Borrelia Projects: This research focuses on the physiology, biochemistry, gene regulation, and pathogenesis of Borrelia burgdorferi, the causative agent of Lyme disease in humans. B. burgdorferi faces several environmental and immunological challenges during its infective cycle and must alter (regulate) gene expression to successfully adapt to these conditions.

Analysis of the B. burgdorferi genome sequence has revealed that there are very few known regulatory proteins in this bacterium. Conspicuously absent are global regulatory proteins such as CRP, LexA, Fnr, IHF, Lrp, and the sigma factors involved in the heat shock response, σ32 and σ24.

This suggests that, compared to other well-characterized pathogenic bacterial systems, the global regulatory systems operating in B. burgdorferi are relatively simple. Clearly, these systems are required for B. burgdorferi to adapt as it encounters very different environments during transfer from an animal reservoir to the tick and then to a human host.

Research efforts in this group have focused on three important regulatory proteins: 1) BosR, a Zn-dependent transcriptional activator that regulates key antioxidant enzymes; 2) σ54, an alternate sigma factor that also regulates certain parts of the oxidative stress response and regulates the osmotic stress response; and 3) vs., which controls the stationary phase of growth and the expression of genes that are critical to the pathogenesis of Lyme disease.


Dr. Gherardini received his doctorate in 1987 from the University of Illinois, studying enzymes involved in the utilization of galactomannans by Bacteroides ovatus. From 1991 to 2001, he was a tenured professor in the Department of Microbiology at the University of Georgia. In 2001, Dr. Gherardini joined the Rocky Mountain Laboratories, where he is chief of the Gene Regulation Section and a senior investigator in the Laboratory of Bacteriology.

Selected Publications

  1. Boyle WK, Groshong AM, Drecktrah D, Boylan JA, Gherardini FC, Blevins JS, Samuels DS, Bourret TJ. DksA Controls the Response of the Lyme Disease Spirochete <i>Borrelia burgdorferi</i> to Starvation. J Bacteriol. 2019;201(4).

  2. Bontemps-Gallo S, Lawrence KA, Richards CL, Gherardini FC. Genomic and phenotypic characterization of Borrelia afzelii BO23 and Borrelia garinii CIP 103362. PLoS One. 2018;13(6):e0199641.

  3. Bontemps-Gallo S, Lawrence KA, Richards CL, Gherardini FC. Borrelia burgdorferi genes, bb0639-0642, encode a putative putrescine/spermidine transport system, PotABCD, that is spermidine specific and essential for cell survival. Mol Microbiol. 2018;108(4):350-360.

  4. Raffel SJ, Williamson BN, Schwan TG, Gherardini FC. Colony formation in solid medium by the relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae. Ticks Tick Borne Dis. 2018;9(2):281-287.

  5. Dulebohn DP, Richards CL, Su H, Lawrence KA, Gherardini FC. Weak Organic Acids Decrease <i>Borrelia burgdorferi</i> Cytoplasmic pH, Eliciting an Acid Stress Response and Impacting RpoN- and RpoS-Dependent Gene Expression. Front Microbiol. 2017;8:1734.

This page was last updated on August 14th, 2019