Proteomic analysis of a ferric uptake regulator mutant of Helicobacter pylori: Regulation of Helicobacter pylori gene expression by ferric uptake regulator and iron

Abstract

The ferric uptake regulator (Fur) protein is a Fe(2+)-dependent transcriptional repressor that binds to the Fur-box of bacterial promoters and down-regulates gene expression. In this study, to investigate global gene regulation by Fur in response to iron in Helicobacter pylori, a causative agent of human gastric diseases, we compared the proteome profiles of the H. pylori strain 26695 and its isogenic fur mutant grown under iron-rich and iron-depleted conditions. In total, 93 protein spots were found to be up- or down-regulated by more than 2-fold by either a fur mutation or iron-depletion. From these, 39 spots were identified by matrix-assisted laser desorption/ionization time of flight analysis to be 29 different proteins of diverse functions, including energy metabolism, transcription and translation, detoxification, biosynthesis of amino acids and nucleotides and production of the cell envelope. Expression of six proteins was found to be higher in the fur mutant than in the wild-type bacteria, indicating Fur-mediated repression. Eleven proteins were activated by Fur; five responded to iron and the others were not iron-responsive. The remaining 12 proteins were not under Fur-regulation but responded to iron in a positive or negative manner. Seven different types of gene regulation via Fur and iron were identified. These findings demonstrate that the H. pylori Fur protein functions as a classical transcriptional repressor but can also function as an activator, providing evidence for the presence of Fur-mediated positive regulation in H. pylori.

Characterization of Key Helicobacter pylori Regulators Identifies a Role for ArsRS in Biofilm Formation

“…Examination of these transcriptome studies en masse demonstrates the vast and overlapping nature of the Fur, NikR, and ArsRS regulons. Furthermore, evidence suggests that these regulators affect expression of each other; nikR and arsR are part of the Fur regulon (23,24), whereas NikR appears to regulate fur (20,25). Given the overlapping nature of these regulatory cascades, it is likely not surprising that the role of each of these factors appears to be expanded compared to what is seen in other bacteria.…”

Differential Proteomics of Helicobacter pylori Associated with Autoimmune Atrophic Gastritis

“…The protein was reported in HP proteome by several works (31,43,60), as well as in the proteomes of some gastric disease-associated HP strains (32). The important role of flagellin A in both bacterial motility and virulence is well documented (61).…”

Small Heat Shock Protein Hsp17.8 Functions as an AKR2A Cofactor in the Targeting of Chloroplast Outer Membrane Proteins in Arabidopsis

“…Isoelectric focusing and two-dimensional SDS-PAGE were performed as described previously (Lee et al, 2004a). Protein samples were applied to 23-cm immobilized pH gradient strips (nonlinear, pH gradient 4-10; Genomine).…”