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Genome-wide screen for temperature-regulated genes of the obligate intracellular bacterium, Rickettsia typhi.

Dreher-Lesnick SM, Ceraul SM, Rahman MS, Azad AF - BMC Microbiol. (2008)

Bottom Line: A large number of differentially expressed genes are still poorly characterized, and either have no known function or are not in the COG database.The microarray results were validated with quantitative real time RT-PCR.Further characterization of the identified genes may provide new insights into the ability of R. typhi to successfully transition between its mammalian and arthropod hosts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology and Immunology, University of Maryland, 660 W, Redwood Street, Room HH324B, Baltimore, MD 21201, USA. sdreh001@umaryland.edu

ABSTRACT

Background: The ability of rickettsiae to survive in multiple eukaryotic host environments provides a good model for studying pathogen-host molecular interactions. Rickettsia typhi, the etiologic agent of murine typhus, is a strictly intracellular gram negative alpha-proteobacterium, which is transmitted to humans by its arthropod vector, the oriental rat flea, Xenopsylla cheopis. Thus, R. typhi must cycle between mammalian and flea hosts, two drastically different environments. We hypothesize that temperature plays a role in regulating host-specific gene expression, allowing R. typhi to survive in mammalian and arthropod hosts. In this study, we used Affymetrix microarrays to screen for temperature-induced genes upon a temperature shift from 37 degrees C to 25 degrees C, mimicking the two different host temperatures in vitro.

Results: Temperature-responsive genes belonged to multiple functional categories including among others, transcription, translation, posttranslational modification/protein turnover/chaperones and intracellular trafficking and secretion. A large number of differentially expressed genes are still poorly characterized, and either have no known function or are not in the COG database. The microarray results were validated with quantitative real time RT-PCR.

Conclusion: This microarray screen identified various genes that were differentially expressed upon a shift in temperature from 37 degrees C to 25 degrees C. Further characterization of the identified genes may provide new insights into the ability of R. typhi to successfully transition between its mammalian and arthropod hosts.

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Differentially expressed R. typhi genes not present on the array. R. typhi genes not present on the array were screened using real time qRT-PCR, and fold change was calculated.
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Figure 3: Differentially expressed R. typhi genes not present on the array. R. typhi genes not present on the array were screened using real time qRT-PCR, and fold change was calculated.

Mentions: We screened 13 R. typhi genes that were not present on the R. prowazekii GeneChip for differential gene expression upon a temperature shift using real time qRT-PCR. Of these, only 3 genes were differentially expressed (Figure 3). Interestingly, another type IV secretory component, virb3, was found to be upregulated, a pattern that is also observed in the arrays (Table 2).


Genome-wide screen for temperature-regulated genes of the obligate intracellular bacterium, Rickettsia typhi.

Dreher-Lesnick SM, Ceraul SM, Rahman MS, Azad AF - BMC Microbiol. (2008)

Differentially expressed R. typhi genes not present on the array. R. typhi genes not present on the array were screened using real time qRT-PCR, and fold change was calculated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2335108&req=5

Figure 3: Differentially expressed R. typhi genes not present on the array. R. typhi genes not present on the array were screened using real time qRT-PCR, and fold change was calculated.
Mentions: We screened 13 R. typhi genes that were not present on the R. prowazekii GeneChip for differential gene expression upon a temperature shift using real time qRT-PCR. Of these, only 3 genes were differentially expressed (Figure 3). Interestingly, another type IV secretory component, virb3, was found to be upregulated, a pattern that is also observed in the arrays (Table 2).

Bottom Line: A large number of differentially expressed genes are still poorly characterized, and either have no known function or are not in the COG database.The microarray results were validated with quantitative real time RT-PCR.Further characterization of the identified genes may provide new insights into the ability of R. typhi to successfully transition between its mammalian and arthropod hosts.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology and Immunology, University of Maryland, 660 W, Redwood Street, Room HH324B, Baltimore, MD 21201, USA. sdreh001@umaryland.edu

ABSTRACT

Background: The ability of rickettsiae to survive in multiple eukaryotic host environments provides a good model for studying pathogen-host molecular interactions. Rickettsia typhi, the etiologic agent of murine typhus, is a strictly intracellular gram negative alpha-proteobacterium, which is transmitted to humans by its arthropod vector, the oriental rat flea, Xenopsylla cheopis. Thus, R. typhi must cycle between mammalian and flea hosts, two drastically different environments. We hypothesize that temperature plays a role in regulating host-specific gene expression, allowing R. typhi to survive in mammalian and arthropod hosts. In this study, we used Affymetrix microarrays to screen for temperature-induced genes upon a temperature shift from 37 degrees C to 25 degrees C, mimicking the two different host temperatures in vitro.

Results: Temperature-responsive genes belonged to multiple functional categories including among others, transcription, translation, posttranslational modification/protein turnover/chaperones and intracellular trafficking and secretion. A large number of differentially expressed genes are still poorly characterized, and either have no known function or are not in the COG database. The microarray results were validated with quantitative real time RT-PCR.

Conclusion: This microarray screen identified various genes that were differentially expressed upon a shift in temperature from 37 degrees C to 25 degrees C. Further characterization of the identified genes may provide new insights into the ability of R. typhi to successfully transition between its mammalian and arthropod hosts.

Show MeSH
Related in: MedlinePlus