Download The role of TolB in Francisella tularensis Erythrocyte Invasion Caleb

The role of TolB in Francisella tularensis Erythrocyte Invasion
Caleb Martin#, Deanna Schmitt#, Alec Florjanczyk#, Edward Beaumont III#, Devin Sindeldecker#,
Donald Primerano *, James Denvir *, and
Joseph Horzempa#
#
Department of Natural Sciences and Mathematics, West Liberty University, West Liberty, WV
*
Genomics and Bioinformatics Core Facility, Marshall University, Huntington, WV
Background and Objectives
Francisella tularensis is the causative agent of a disease called tularemia. In the murine model
of tularemia, F. tularensis bacteria invade erythrocytes. The bacteria do not replicate within
erythrocytes. However, residing within these cells allows for increased colonization of the tick
vector following acquisition of a blood meal – a situation that presumably increases
transmission. We hypothesized that F. tularensis genes involved in erythrocyte invasion would
be upregulated during exposure to these host cells.
Methods
RNAseq was used to identify differentially expressed F. tularensis genes in response to
erythrocytes. Deletion of F. tularensis LVS tolB was generated via homologous recombination.
Gentamicin protection assays were used to evaluate erythrocyte invasion.
Results
RNAseq revealed that approximately 7% of the F. tularensis genes were induced when exposed
to erythrocytes. One of the most highly upregulated genes, tolB, encodes a protein responsible
for the detection of environmental signals in other bacteria. Deletion of tolB significantly
reduced the ability of F. tularensis to invade erythrocytes.
Discussion and Conclusions
Erythrocyte cues stimulate expression of F. tularensis genes required for erythrocyte invasion.
TolB is required for erythrocyte invasion by F. tularensis.
Supported by NIH Grant P20GM103434 to the West Virginia IDeA Network for Biomedical
Research Excellence and through the WV Research Challenge Fund [HEPC.dsr.14.13]