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Transcriptional profiling of Bacillus anthracis Sterne (34F2) during iron starvation.

Carlson PE, Carr KA, Janes BK, Anderson EC, Hanna PC - PLoS ONE (2009)

Bottom Line: Two genes encoding putative internalin proteins were chosen for further study.This attenuation was amplified in a double mutant strain.These data define the transcriptional changes induced during growth in low iron conditions and illustrate the potential of this dataset in the identification of putative virulence determinants for future study.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

ABSTRACT
Lack of available iron is one of many environmental challenges that a bacterium encounters during infection and adaptation to iron starvation is important for the pathogen to efficiently replicate within the host. Here we define the transcriptional response of B. anthracis Sterne (34F(2)) to iron depleted conditions. Genome-wide transcript analysis showed that B. anthracis undergoes considerable changes in gene expression during growth in iron-depleted media, including the regulation of known and candidate virulence factors. Two genes encoding putative internalin proteins were chosen for further study. Deletion of either gene (GBAA0552 or GBAA1340) resulted in attenuation in a murine model of infection. This attenuation was amplified in a double mutant strain. These data define the transcriptional changes induced during growth in low iron conditions and illustrate the potential of this dataset in the identification of putative virulence determinants for future study.

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Related in: MedlinePlus

Changes in B. anthracis gene expression induced by iron starvation over time.Hierarchical clustering of genes identified as statistically significant by J5 test across two independent microarray experiments. Fluorescence intensities were normalized as described in the methods. Normalized intensity values from two experiments were input into Gene Pattern together and clustered using the Pearson correlation. Genes clustered into four groups, induced with a peak at three hours (A), induced at three and four hours (B), induced at four hours (C), and repressed (D). Data shown are normalized intensity values over time for samples grown in IDM only.
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pone-0006988-g002: Changes in B. anthracis gene expression induced by iron starvation over time.Hierarchical clustering of genes identified as statistically significant by J5 test across two independent microarray experiments. Fluorescence intensities were normalized as described in the methods. Normalized intensity values from two experiments were input into Gene Pattern together and clustered using the Pearson correlation. Genes clustered into four groups, induced with a peak at three hours (A), induced at three and four hours (B), induced at four hours (C), and repressed (D). Data shown are normalized intensity values over time for samples grown in IDM only.

Mentions: Those genes exhibiting significantly altered expression following four hours of growth in IDM were put into Gene Pattern [19] for hierarchical clustering (Figure 2). Figure 2A shows a clustering of log2 transformed normalized intensity values of all gene found to be significantly changed at four hours. Data for the entire timecourse in IDM are shown for these genes to illustrate the observed changes over time in this medium. The clustered data demonstrate a clear pattern of transcriptional regulation over time. Cluster A represents a small subset of genes that appear to peak at three hours, although their expression remains significantly higher at four hours (compared to IRM). Cluster B represent genes that peak at three hours and remain highly expressed through the end of the experiment while cluster C represents genes with a peak in expression at four hours. Finally, cluster D consists of those genes exhibiting a decrease in expression during iron starvation.


Transcriptional profiling of Bacillus anthracis Sterne (34F2) during iron starvation.

Carlson PE, Carr KA, Janes BK, Anderson EC, Hanna PC - PLoS ONE (2009)

Changes in B. anthracis gene expression induced by iron starvation over time.Hierarchical clustering of genes identified as statistically significant by J5 test across two independent microarray experiments. Fluorescence intensities were normalized as described in the methods. Normalized intensity values from two experiments were input into Gene Pattern together and clustered using the Pearson correlation. Genes clustered into four groups, induced with a peak at three hours (A), induced at three and four hours (B), induced at four hours (C), and repressed (D). Data shown are normalized intensity values over time for samples grown in IDM only.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2742718&req=5

pone-0006988-g002: Changes in B. anthracis gene expression induced by iron starvation over time.Hierarchical clustering of genes identified as statistically significant by J5 test across two independent microarray experiments. Fluorescence intensities were normalized as described in the methods. Normalized intensity values from two experiments were input into Gene Pattern together and clustered using the Pearson correlation. Genes clustered into four groups, induced with a peak at three hours (A), induced at three and four hours (B), induced at four hours (C), and repressed (D). Data shown are normalized intensity values over time for samples grown in IDM only.
Mentions: Those genes exhibiting significantly altered expression following four hours of growth in IDM were put into Gene Pattern [19] for hierarchical clustering (Figure 2). Figure 2A shows a clustering of log2 transformed normalized intensity values of all gene found to be significantly changed at four hours. Data for the entire timecourse in IDM are shown for these genes to illustrate the observed changes over time in this medium. The clustered data demonstrate a clear pattern of transcriptional regulation over time. Cluster A represents a small subset of genes that appear to peak at three hours, although their expression remains significantly higher at four hours (compared to IRM). Cluster B represent genes that peak at three hours and remain highly expressed through the end of the experiment while cluster C represents genes with a peak in expression at four hours. Finally, cluster D consists of those genes exhibiting a decrease in expression during iron starvation.

Bottom Line: Two genes encoding putative internalin proteins were chosen for further study.This attenuation was amplified in a double mutant strain.These data define the transcriptional changes induced during growth in low iron conditions and illustrate the potential of this dataset in the identification of putative virulence determinants for future study.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

ABSTRACT
Lack of available iron is one of many environmental challenges that a bacterium encounters during infection and adaptation to iron starvation is important for the pathogen to efficiently replicate within the host. Here we define the transcriptional response of B. anthracis Sterne (34F(2)) to iron depleted conditions. Genome-wide transcript analysis showed that B. anthracis undergoes considerable changes in gene expression during growth in iron-depleted media, including the regulation of known and candidate virulence factors. Two genes encoding putative internalin proteins were chosen for further study. Deletion of either gene (GBAA0552 or GBAA1340) resulted in attenuation in a murine model of infection. This attenuation was amplified in a double mutant strain. These data define the transcriptional changes induced during growth in low iron conditions and illustrate the potential of this dataset in the identification of putative virulence determinants for future study.

Show MeSH
Related in: MedlinePlus