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Individual Mycobacterium tuberculosis universal stress protein homologues are dispensable in vitro.

Hingley-Wilson SM, Lougheed KE, Ferguson K, Leiva S, Williams HD - Tuberculosis (Edinb) (2010)

Bottom Line: However, proteomic and transcriptomic analyses have shown that a number of usp genes are significantly upregulated under hypoxic conditions and in response to nitric oxide and carbon monoxide, as well as during M. tuberculosis infection of macrophage cell lines.Six of these USPs are part of the DosR regulon and this, along with their expression pattern and the phenotypes of usp mutants in other bacterial species, suggests a potential role in the persistence and/or intracellular survival of Mtb.The possibility remains that these USPs are functionally redundant in Mtb.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.

ABSTRACT
Mycobacterium tuberculosis has 10 universal stress proteins, whose function is unknown. However, proteomic and transcriptomic analyses have shown that a number of usp genes are significantly upregulated under hypoxic conditions and in response to nitric oxide and carbon monoxide, as well as during M. tuberculosis infection of macrophage cell lines. Six of these USPs are part of the DosR regulon and this, along with their expression pattern and the phenotypes of usp mutants in other bacterial species, suggests a potential role in the persistence and/or intracellular survival of Mtb. Knock-out mutants of individual usp genes encoding the USPs Rv1996, Rv2005c, Rv2026c and Rv2028c were generated and their growth and survival under hypoxic and other stress conditions examined. Although the majority of usp genes are highly induced in hypoxic conditions, mutation did not affect the long term survival of Mtb under these conditions, or in response to a range of stress conditions chosen to represent the environmental onslaughts experienced by the bacillus during an infection, nor during infection of mouse and human - derived macrophage cell lines. The possibility remains that these USPs are functionally redundant in Mtb.

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The M. tuberculosis usp mutants exhibited no survival defect in response to a range of stress conditions. A number of other stress conditions were also tested (see Table 1), but no survival phenotype was observed when comparing the usp mutants to the wildtype H37Rv. As examples, the results for A) low pH and B) Nitrosative stress (5 mM GSNO) are shown. Error bars represent the standard deviations of 3 independent cultures.
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fig4: The M. tuberculosis usp mutants exhibited no survival defect in response to a range of stress conditions. A number of other stress conditions were also tested (see Table 1), but no survival phenotype was observed when comparing the usp mutants to the wildtype H37Rv. As examples, the results for A) low pH and B) Nitrosative stress (5 mM GSNO) are shown. Error bars represent the standard deviations of 3 independent cultures.

Mentions: Mining of publically available Mtb microarray data identified a range of stress conditions that lead to the upregulation of one or more USPs (Table 1). Multiple studies have shown that 6 usp genes are upregulated by low oxygen and NO in a DosR dependent manner; 7 usp genes are upregulated by H2O2 and by DNA damaging agents UV light and mitomycin C, which is interesting in the context of the importance of a number of USPs from E. coli having a putative role in DNA protection.50,51 Therefore, these conditions together with others (Table 1), chosen to represent the predicted environmental conditions experienced in the disease state, were used to screen the usp mutants and complemented strains for survival defects compared to wildtype. The screens were performed in 24-well plates and CFU platings used to determine the survival of the cultures following the stress challenge. In all cases the survival of the usp mutants was found to be no different from that of the wildtype. None of the stress agents tested yielded a phenotype for any of the mutants. A representative selection of the results is shown in Figure 4.


Individual Mycobacterium tuberculosis universal stress protein homologues are dispensable in vitro.

Hingley-Wilson SM, Lougheed KE, Ferguson K, Leiva S, Williams HD - Tuberculosis (Edinb) (2010)

The M. tuberculosis usp mutants exhibited no survival defect in response to a range of stress conditions. A number of other stress conditions were also tested (see Table 1), but no survival phenotype was observed when comparing the usp mutants to the wildtype H37Rv. As examples, the results for A) low pH and B) Nitrosative stress (5 mM GSNO) are shown. Error bars represent the standard deviations of 3 independent cultures.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2914252&req=5

fig4: The M. tuberculosis usp mutants exhibited no survival defect in response to a range of stress conditions. A number of other stress conditions were also tested (see Table 1), but no survival phenotype was observed when comparing the usp mutants to the wildtype H37Rv. As examples, the results for A) low pH and B) Nitrosative stress (5 mM GSNO) are shown. Error bars represent the standard deviations of 3 independent cultures.
Mentions: Mining of publically available Mtb microarray data identified a range of stress conditions that lead to the upregulation of one or more USPs (Table 1). Multiple studies have shown that 6 usp genes are upregulated by low oxygen and NO in a DosR dependent manner; 7 usp genes are upregulated by H2O2 and by DNA damaging agents UV light and mitomycin C, which is interesting in the context of the importance of a number of USPs from E. coli having a putative role in DNA protection.50,51 Therefore, these conditions together with others (Table 1), chosen to represent the predicted environmental conditions experienced in the disease state, were used to screen the usp mutants and complemented strains for survival defects compared to wildtype. The screens were performed in 24-well plates and CFU platings used to determine the survival of the cultures following the stress challenge. In all cases the survival of the usp mutants was found to be no different from that of the wildtype. None of the stress agents tested yielded a phenotype for any of the mutants. A representative selection of the results is shown in Figure 4.

Bottom Line: However, proteomic and transcriptomic analyses have shown that a number of usp genes are significantly upregulated under hypoxic conditions and in response to nitric oxide and carbon monoxide, as well as during M. tuberculosis infection of macrophage cell lines.Six of these USPs are part of the DosR regulon and this, along with their expression pattern and the phenotypes of usp mutants in other bacterial species, suggests a potential role in the persistence and/or intracellular survival of Mtb.The possibility remains that these USPs are functionally redundant in Mtb.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.

ABSTRACT
Mycobacterium tuberculosis has 10 universal stress proteins, whose function is unknown. However, proteomic and transcriptomic analyses have shown that a number of usp genes are significantly upregulated under hypoxic conditions and in response to nitric oxide and carbon monoxide, as well as during M. tuberculosis infection of macrophage cell lines. Six of these USPs are part of the DosR regulon and this, along with their expression pattern and the phenotypes of usp mutants in other bacterial species, suggests a potential role in the persistence and/or intracellular survival of Mtb. Knock-out mutants of individual usp genes encoding the USPs Rv1996, Rv2005c, Rv2026c and Rv2028c were generated and their growth and survival under hypoxic and other stress conditions examined. Although the majority of usp genes are highly induced in hypoxic conditions, mutation did not affect the long term survival of Mtb under these conditions, or in response to a range of stress conditions chosen to represent the environmental onslaughts experienced by the bacillus during an infection, nor during infection of mouse and human - derived macrophage cell lines. The possibility remains that these USPs are functionally redundant in Mtb.

Show MeSH
Related in: MedlinePlus