Multiple ehrlichia chaffeensis genes critical for its persistent infection in a vertebrate host are identified by random mutagenesis coupled with in vivo infection assessment

Ying Wang, Arathy D.S. Nair, Andy Alhassan, Deborah C. Jaworski, Huitao Liu, Kathleen Trinkl, Paidashe Hove, Charan K. Ganta, Nicole Burkhardt, Ulrike G. Munderloh, Roman R. Ganta

Research output: Contribution to journalArticlepeer-review

Abstract

Ehrlichia chaffeensis, a tick-transmitted obligate intracellular rickettsial agent, causes human monocytic ehrlichiosis. In recent reports, we described substantial advances in developing random and targeted gene disruption methods to investigate the functions of E. chaffeensis genes. We reported earlier that the Himar1 transposon-based random mutagenesis is a valuable tool in defining E. chaffeensis genes critical for its persistent growth in vivo in reservoir and incidental hosts. The method also aided in extending studies focused on vaccine development and immunity. Here, we describe the generation and mapping of 55 new mutations. To define the critical nature of the bacterial genes, infection experiments were carried out in the canine host with pools of mutant organisms. Infection evaluation in the physiologically relevant host by molecular assays and by xenodiagnoses allowed the identification of many proteins critical for the pathogen's persistent in vivo growth. Genes encoding proteins involved in biotin biosynthesis, protein synthesis and fatty acid biosynthesis, DNA repair, electron transfer, and a component of a multidrug resistance (MDR) efflux pump were concluded to be essential for the pathogen's in vivo growth. Three known immunodominant membrane proteins, i.e., two 28-kDa outer membrane proteins (P28/OMP) and a 120-kDa surface protein, were also recognized as necessary for the pathogen's obligate intracellular life cycle. The discovery of many E. chaffeensis proteins crucial for its continuous in vivo growth will serve as a major resource for investigations aimed at defining pathogenesis and developing novel therapeutics for this and related pathogens of the rickettsial family Anaplasmataceae.

Original languageEnglish (US)
Article numbere00316
JournalInfection and immunity
Volume88
Issue number10
DOIs
StatePublished - Oct 2020

Bibliographical note

Funding Information:
This work was supported by the PHS grant AI070908 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA (https://www.niaid.nih.gov/), to R.R.G.

Keywords

  • Ehrlichia chaffeensis
  • In vivo screening
  • Mutagenesis
  • Rickettsial
  • Tick-borne pathogens
  • Tickborne diseases
  • Transposon

Fingerprint Dive into the research topics of 'Multiple ehrlichia chaffeensis genes critical for its persistent infection in a vertebrate host are identified by random mutagenesis coupled with in vivo infection assessment'. Together they form a unique fingerprint.

Cite this