Characterization of the Fur Regulon in Pseudomonas syringae pv. tomato DC3000

Abstract

The plant pathogen Pseudomonas syringae pv. tomato DC3000 (DC3000) is found in a wide variety of environments and must monitor and respond to various environmental signals such as the availability of iron, an essential element for bacterial growth. An important regulator of iron homeostasis is Fur (ferric uptake regulator), and here we present the first study of the Fur regulon in DC3000. Using chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-seq), 312 chromosomal regions were highly enriched by coimmunoprecipitation with a C-terminally tagged Fur protein. Integration of these data with previous microarray and global transcriptome analyses allowed us to expand the putative DC3000 Fur regulon to include genes both repressed and activated in the presence of bioavailable iron. Using nonradioactive DNase I footprinting, we confirmed Fur binding in 41 regions, including upstream of 11 iron-repressed genes and the iron-activated genes encoding two bacterioferritins (PSPTO_0653 and PSPTO_4160), a ParA protein (PSPTO_0855), and a two-component system (TCS) (PSPTO_3382 to PSPTO_3380).

Fur-Mediated Global Regulatory Circuits in Pathogenic Neisseria Species

“…Recently, global analyses of iron-and/or Fur-responsive transcriptomes of diverse bacterial pathogens, such as H. pylori, Pseudomonas syringae, Vibrio cholerae, Yersinia pestis, Haemophilus influenzae, S. enterica serovar Typhimurium, and Listeria monocytogenes, have revealed a number of novel regulatory roles for Fur (12,20,40,56,68,94,101,102,107). First, Fur has been demonstrated to repress transcription even in the absence of iron, a process termed apo-Fur regulation (13) (Fig.…”

Fur-Mediated Activation of Gene Transcription in the Human Pathogen Neisseria gonorrhoeae

“…Fur is also able to repress transcription without the presence of a ferrous cofactor in a process termed apo-Fur-mediated regulation (17,23,24). In addition to apo-Furmediated repression, a subset of genes has been found to be upregulated under iron-replete conditions, suggesting that Fur can also function as a transcriptional activator (10,14,23,30,32).…”

The Iron Stimulon and Fur Regulon of Geobacter sulfurreducens and Their Role in Energy Metabolism

“…Genes previously found to be involved in iron homeostasis in other bacteria, such as Feo iron transporters and Fur, were found to be downregulated (31,32). Uptake of iron in its Fe(II) form has been shown to be dependent on a variety of transport systems (33).…”