POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
POSTERS - BLAST X - University of Utah
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>BLAST</strong> X Poster #59<br />
CHARACTERIZATION OF FliZ AS AN ACTIVATOR OF FLAGELLAR GENES IN<br />
SALMONELLA ENTERICA SEROVAR TYPHIMURIUM<br />
Supreet Saini 1 , Phillip Aldridge 2,3 , and Christopher Rao 1<br />
Department <strong>of</strong> Chemical and Biomolecular Engineering, <strong>University</strong> <strong>of</strong> Illinois at Urbana-<br />
Champaign, Urbana, Illinois 61801, 1<br />
Centre for Bacterial Cell Biology, Newcastle <strong>University</strong>, Framlington Place, Newcastle upon<br />
Tyne NE2 4HH, United Kingdom, 2<br />
Institute for Cell and Molecular Biosciences, Newcastle <strong>University</strong>, Framlington Place,<br />
Newcastle upon Tyne NE2 4HH, United Kingdom 3<br />
Flagellar assembly proceeds in a sequential manner, beginning at the base and<br />
concluding with the filament. A critical aspect <strong>of</strong> assembly is that gene expression is coupled to<br />
assembly. When cells transition from a nonflagellated to a flagellated state, gene expression is<br />
sequential, reflecting the manner in which the flagellum is made. A key mechanism for<br />
establishing this temporal hierarchy is the σ 28 -FlgM checkpoint, which couples the expression <strong>of</strong><br />
late flagellar (Pclass3) genes to the completion <strong>of</strong> the hook-basal body. In this work, we<br />
investigated the role <strong>of</strong> FliZ in coupling middle flagellar (Pclass2) gene expression to assembly<br />
in Salmonella enterica serovar Typhimurium (Salmonella). We also demonstrate that significant<br />
cross talk exists between different secretion systems in Salmonella with FliZ as the cross talk<br />
element. Specifically, we show that FliZ is also an activator <strong>of</strong> Salmonella Pathogenicity Island-1<br />
(SPI1) encoded virulence genes and the fim, lpf, std, saf, bcf, stb, stc, stf, and sth loci encoded<br />
fimbriae in Salmonella. We demonstrate that FliZ is an FlhD4C2-dependent activator <strong>of</strong><br />
Pclass2/middle gene expression. Our results suggest that FliZ regulates the concentration <strong>of</strong><br />
FlhD4C2 posttranslationally which leads to faster induction <strong>of</strong> Pclass2/middle genes. We also<br />
demonstrate that FliZ functions independently <strong>of</strong> the flagellum-specific sigma factor σ 28 and the<br />
filament-cap chaperone/ FlhD4C2 inhibitor FliT. We correlate our gene expression experiments<br />
by discussing the role <strong>of</strong> FliZ in flagellar biosynthesis during swimming and swarming motility.<br />
FliZ was found to effect SPI1 activity levels in a HilD dependent posttranslational manner and its<br />
effect on type I fimbriae gene expression was found to be FimZ dependent.<br />
110