Temporal Global Changes in Gene Expression during Temperature Transition in Yersinia pestis

Abstract

DNA microarrays encompassing the entire genome of Yersinia pestis were used to characterize global regulatory changes during steady-state vegetative growth occurring after shift from 26 to 37°C in the presence and absence of Ca 2؉ . Transcriptional profiles revealed that 51, 4, and 13 respective genes and open reading frames (ORFs) on pCD, pPCP, and pMT were thermoinduced and that the majority of these genes carried by pCD were downregulated by Ca 2؉ . In contrast, Ca 2؉ had little effect on chromosomal genes and ORFs, of which 235 were thermally upregulated and 274 were thermally downregulated. The primary consequence of these regulatory events is profligate catabolism of numerous metabolites available in the mammalian host.Bubonic plague caused by Yersinia pestis is generally recognized as the most devastating acute infectious disease experienced by mankind. It is therefore of interest that this organism has evolved within the last 10,000 years from Yersinia pseudotuberculosis (1), known to cause chronic enteropathogenic disease. Despite their very close resemblance, plague bacilli have both lost central genes of intermediary metabolism retained in its predecessor and acquired unique genes by lateral transfer (7). For example, even though early studies showed that Y. pestis possesses functional Embden-Meyerhof (28) and Entner-Doudoroff (20) pathways plus a complete tricarboxylic acid (TCA) cycle (13, 27), the species-specific absence of detectable glucose 6-phosphate dehydrogenase (Zwf) prevents use of hexose via the pentose-phosphate pathway (21). Similarly, loss of aspartase (AspA) activity in Y. pestis but not Y. pseudotuberculosis prevents complete catabolism of L-glutamic acid, which undergoes conversion and excretion as L-aspartate (12). In addition, Y. pestis possesses additional species-specific mutations that cause nutritional requirements at 26°C, prevent utilization of potential metabolites, and eliminate host cell invasins and adhesins (7); these events are now characterized by genomic sequencing (11, 23). The nature of nutritional requirements at 37°C is more complex and, as noted below, dependent upon plasmid profile, the presence or absence of Ca 2ϩ , Na ϩ , dicarboxylic amino acids, and regulatory functions addressed in this report.Established functions unique to Y. pestis are encoded by species-specific ϳ10-kb pPCP and ϳ100-kb pMT. The former encodes plasminogen activator (Pla) required for tissue invasion from dermal sites infected by fleabite whereas the structural genes for anti-phagocytic capsular fraction 1 (Caf1) and murine toxin (MT), required for survival in the flea, reside on pMT (7,25). Plague bacilli and the enteropathogenic yersiniae share a ϳ70-kb plasmid (pCD in Y. pestis) encoding a type III protein secretion system (TTSS) that delivers cytotoxins termed Yops to the cytosol of professional and nonprofessional phagocytes (8) and excretes soluble LcrV (V antigen), which inhibits generation of proinflammatory cytokines by upregulating interleukin-10 (6). These functions provide th...

Current Trends in Plague Research: From Genomics to Virulence

“…14 A few groups have used whole-genome DNA microarray analysis to investigate transcriptional regulation upon the upshift of growth temperature from 26ºC to 37ºC in a chemically defined medium with or without 2.5 mM CaCl. 13,14 Genes which were upregulated quickly after the shift to 37ºC may be valid Y. pestis virulence factor candidates, since early changes in transcriptional expression due to temperature shift probably reflect adaptation to the host rather than changes solely integral to the onset of bacteriostasis. Transcriptional profiles reported by Motin et al 13 revealed thermal induction of 51, 4 and 13 genes or open reading frames on pCD1, pPCP and pMT, respectively.…”

Practical applications of structural genomics technologies for mutagen research

“…We specifically targeted proteins encoded by genes implicated in virulence for which there was little or no functional annotation. Expression array experiments with Y. pestis, the etiological agent of bubonic plague, identified a large number of genes that are upregulated in host-mimetic conditions [43]. More than 30% of the implicated genes were annotated as putative or conserved hypothetical, here we will discuss our efforts to characterize one protein, whose gene was annotated as hypothetical conserved protein.…”

“…The gene with locus tag YPO0407 is upregulated in host-mimetic conditions [43] and was annotated as a hypothetical conserved protein. Starting with only the gene expression data and the annotated sequence, we targeted the protein encoded by YPO0407 for expression and structure determination.…”

Regulation of Yersina pestis Virulence by AI-2 Mediated Quorum Sensing

“…[2] Furthermore, Y. pestis gene expression array studies carried out at LLNL have established a correlation between expression of known virulence factors and genes involved in processing of the AI-2 quorum sensing signal. [6] Scope This was a basic research project that was intended to provide new insights into bacterial intercellular communication and how it is used to regulate virulence in Y. pestis. It is known that many bacteria use intercellular signaling molecules to orchestrate gene expression and cellular function.…”