Changes in Bacillus anthracis CodY regulation under host-specific environmental factor deprived conditions

Abstract

BackgroundHost-specific environmental factors induce changes in Bacillus anthracis gene transcription during infection. A global transcription regulator, CodY, plays a pivotal role in regulating central metabolism, biosynthesis, and virulence in B. anthracis. In this study, we utilized RNA-sequencing to assess changes in the transcriptional patterns of CodY-regulated B. anthracis genes in response to three conditions of environmental starvation: iron, CO2, or glucose deprivation. In addition, we performed chromatin immunoprecipitation on newly identified CodY-mediated genes.ResultsEnvironmental deprivation induced transcriptional changes in CodY-regulated genes in both wild-type and codY null strains, and both CodY-specific and environment-specific patterns were observed. In the iron-depleted condition, overexpression of iron homeostasis genes was observed independent of codY deletion; however, transcription of siderophore and amino acid biosynthesis genes was CodY dependent. Although CodY has a significant regulatory role in central metabolism and the carbon overflow pathway, metabolism-associated genes exhibited CodY-independent expression patterns under glucose starvation. Genes that were differentially expressed in response to CO2 availability showed CodY-dependent regulation, though their maximal expression did require a supply of CO2/bicarbonate.ConclusionsWe speculate that CodY regulates the expression of environmental-responsive genes in a hierarchical manner and is likely associated with other transcription regulators that are specific for a particular environmental change.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3004-8) contains supplementary material, which is available to authorized users.

CodY, ComA, DegU and Spo0A Controlling Lipopeptides Biosynthesis in Bacillus amyloliquefaciens fmbJ

“…As a global negative regulator, CodY is usually a transcriptional repressor of its target genes, which binds to the promoter of these genes or directly to genes to block the binding of RNA polymerase (Kim, Jung, & Chai, 2016). From Fig.…”

Soil Bacterial Function Associated With Stylo (Legume) and Bahiagrass (Grass) Is Affected More Strongly by Soil Chemical Property Than by Bacterial Community Composition

“…In this context, it is not surprising that the bacterial community composition was more closely related (higher correlation coefficient) with functional gene abundance than with soil enzyme activity. Although functional genes are inherent to bacterial taxa, their transcription and translation are greatly regulated by environmental conditions (Schreiber et al, 2007; Kim et al, 2016; Hockenberry et al, 2017). Taking nitrate respiration as example, a serial of functional genes ( nar , nir ) are regulated by anaerobic condition and nitrate presence via transcription network in Pseudomonas aeruginosa (Schreiber et al, 2007).…”

Heme catabolism in the causative agent of anthrax

“…These include a 2.39‐fold increase in early macrophage infections and a ~ twofold increase when either of the thiol‐stress response regulators Spx1A or Spx2A were overexpressed (Dixon et al , ; Bergman et al , ). The largest change we found was again from the Kim et al study where hmoB was downregulated 6.6‐fold in Δ codY strains in aeriated Ristroph media lacking bicarbonate/CO 2 (Kim et al , ). The increase transcription observed in macrophages does correlate with our observation that loss of this gene makes bacilli more susceptible to macrophage‐based killing.…”

“…Activation of hmoA by Spx, which is in turn repressed by PerR, would fit with the model proposed by Chandrangsu and Helmann in B. subtilis . Both IsdG and HmoA appear to be regulated by the global virulence regulator CodY, which is not surprising considering CodY has been implicated in heme iron acquisition before (Château et al , ; Kim et al , ). In studies done by Kim et al neither hmoA nor isdG showed increased expression under iron‐starved conditions unless codY was deleted (Kim et al , ).…”

“…Both IsdG and HmoA appear to be regulated by the global virulence regulator CodY, which is not surprising considering CodY has been implicated in heme iron acquisition before (Château et al , ; Kim et al , ). In studies done by Kim et al neither hmoA nor isdG showed increased expression under iron‐starved conditions unless codY was deleted (Kim et al , ). However, this distinction may be purely semantic since HmoA and IsdG appear to be completely redundant in a mouse model of infection, showing no significant defect in virulence if either one is present.…”