Mycobacterial Stationary Phase Induced by Low Oxygen Tension: Cell Wall Thickening and Localization of the 16-Kilodalton α-Crystallin Homolog

Cunningham, Adam F.; Spreadbury, Claire L.

doi:10.1128/jb.180.4.801-808.1998

Cited by 328 publications

(171 citation statements)

References 45 publications

(45 reference statements)

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“…In previous in vivo studies, over-expression of HSP 16.3 at the end of log-phase growth in M. tuberculosis resulted in an enhanced resistance to autolysis [5]. Our results showing a protective effect of MTB HSP 16.3 against thermal killing in E. coli are consistent with previous studies on the importance of MTB HSP 16.3 expression in M. tuberculosis [5][6][7]. Although the role of MTB HSP 16.3 is not completely understood, these experiments suggest that MTB HSP 16.3 may provide protection against cell death in M. tuberculosis.…”

Section: Discussionsupporting

confidence: 92%

Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP 16.3 and human αB‐crystallin

Valdez¹,

Clark

et al. 2002

European Journal of Biochemistry

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Mycobacterium tuberculosis heat shock protein 16.3 (MTB HSP 16.3) accumulates as the dominant protein in the latent stationary phase of tuberculosis infection. MTB HSP 16.3 displays several characteristics of small heat shock proteins (sHsps): its expression is increased in response to stress, it protects against protein aggregation in vitro, and it contains the core Ôa-crystallinÕ domain found in all sHsps. In this study we characterized the chaperone activity of recombinant MTB HSP 16.3 in several different assays and compared the results to those obtained with recombinant human aB-crystallin, a well characterized member of the sHsp family. Recombinant MTB HSP 16.3 was expressed in Escherichia coli and purified to apparent homogeneity. Similar to aB-crystallin, MTB HSP16.3 suppressed citrate synthase aggregation and in the presence of 3.5 mM ATP the chaperone activity was enhanced by twofold. ATP stabilized MTB HSP 16.3 against proteolysis by chymotrypsin, and no effect was observed with ATPcS, a nonhydrolyzable analog of ATP. Increased expression of MTB HSP 16.3 resulted in protection against thermal killing in E. coli at 48°C. While the sequence similarity between human aB-crystallin and MTB HSP 16.3 is only 18%, these results suggest that the functional similarities between these proteins containing the core Ôa-crystallinÕ domain are much closer.Keywords: ATP; human aB-crystallin; molecular chaperone; Mycobacterium tuberculosis HSP 16.3; small heat shock proteins.One-third of the world's population is infected with latent inactive tuberculosis and active tuberculosis is the leading cause of death due to an infectious disease [1]. Each year, new infections occur in 54 million people; 6.8 million people develop clinical disease, and 2.4 million cases result in death [2]. There is still limited knowledge of the molecular pathogenesis of the latent stage of this organism [3]. Individuals who have been infected with Mycobacterium tuberculosis can harbor stable dormant bacilli for decades before developing an active infection later in life [4]. Recent reports indicate an important role for M. tuberculosis (MTB) heat shock protein (HSP) 16.3 in the survival of MTB during prolonged periods of infection [5][6][7]. It was shown that MTB HSP 16.3, initially described as the immunodominant 14-or 16-kDa antigen [8][9][10][11], was a major component in tuberculosis infection in humans and played an important role in enhancing protein stability and survival [5]. Eighty-five percent of patients with active tuberculosis showed a positive reaction to this antigen, suggesting that this protein expressed in vivo had a key role in MTB infection [11,12]. The 14K antigen was later renamed MTB HSP 16.3 [13]. MTB HSP 16.3 accumulates to become the dominant protein in the latent stationary phase of M. tuberculosis infection [7]. Over-expression of HSP 16.3 in log phase growth of M. tuberculosis slowed the growth rate and protected against stationary phase autolysis in vitro [7]. MTB HSP 16.3 has been characterized as a membrane asso...

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Section: Discussionsupporting

confidence: 92%

Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP 16.3 and human αB‐crystallin

Valdez¹,

Clark

et al. 2002

European Journal of Biochemistry

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“…Both genes are not present in M. smegmatis [9,10]. Furthermore, a thickening of the cell wall was described for anaerobic M. tuberculosis but not for anaerobic M. smegmatis culture [11]. We propose two interpretations of the discrepancies between the similarities in the physiological dormancy response we have demonstrated and the di¡erences at the molecular and morphological level between the two mycobacteria identi¢ed to date.…”

Section: Discussionmentioning

confidence: 67%

“…The demonstrated physiological similarities between M. smegmatis and M. tuberculosis are intriguing in the light of the recently started molecular analysis of anaerobic dormant M. tuberculosis [9^12]. Two genes were proposed to play a role in the dormancy response: the sigma factor sigF [9] and the chaperon alpha crystallin [10,11]. Both genes are not present in M. smegmatis [9,10].…”

Section: Discussionmentioning

confidence: 99%

Oxygen depletion induced dormancy in Mycobacterium smegmatis

Dick¹

1998

FEMS Microbiology Letters

112

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We report here that the physiological behaviour of the fastgrowing saprophytic Mycobacterium smegmatis under in vitro oxygen-depletion and reactivation conditions is strikingly similar to the characteristics shown by the slowgrowing pathogenic M. tuberculosis. M. smegmatis died rapidly when shifted abruptly from aerobic to anaerobic conditions. In contrast to the lethal shock of abrupt oxygen depletion, the slow depletion through a selfgenerated oxygen gradient permitted an adaptation to a persistent state which showed increased resistance against the bactericidal effects of anaerobiosis. The anaerobic persistent culture did not synthesise DNA and showed synchronised division upon reactivation in oxygen rich medium, indicating that the persistent bacilli are uniformly arrested at a defined stage of the cell cycle. Upon reactivation the persistent culture started synthesising DNA only after the first cell division, suggesting that the persistent cells contain two chromosomes. Furthermore, the persistent culture developed sensitivity to metronidazole and resistance against ofloxacin. These results suggest that M. smegmatis might be useful as a fastgrowing non-pathogenic model for comparative molecular analyses of mycobacterial dormancy. z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

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“…To verify the results obtained by microarray analysis (Table 3) Hutter and Dick, 1999;hspX, Yuan et al, 1996;Cunningham and Spreadbury, 1998), the two-component system Rv 3132c and Rv 3133c (Sherman et al, 2001) or heterologous organisms (the five members of the Usp family; Nyström and Neidhardt, 1994;Diez et al, 2000;Gustavsson et al, 2002) have provided evidence suggesting that some of these genes may play a role in mycobacterial persistence and/or in resistance against RNI toxicity (see below). In addition, two genes (Rv 2627c and Rv 3131) were also studied exhibiting a high degree of RNI inducibility that encode conserved hypothetical proteins of unknown functions.…”

Section: Validation Of the Microarray Gene Profiling System By Real-tmentioning

confidence: 96%

The effects of reactive nitrogen intermediates on gene expression inMycobacterium tuberculosis

Ohno¹,

Zhu²,

Mohan³

et al. 2003

Cellular Microbiology

180

161

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SummaryNitric oxide (NO) and related reactive nitrogen intermediates (RNI) are effective antimycobacterial agents and signal-transducing molecules. The present study uses microarray analysis to examine the effects of RNI on Mycobacterium tuberculosis gene expression. A common set of 53 genes was regulated by two chemically distinct nitric oxide donors. For a subset of the RNI-inducible genes, evidence exists suggesting that they may play a role in promoting survival of the tubercle bacillus in the host. Results obtained from studies based on a murine experimental tuberculosis model involving nos2 -deficient mice suggest that RNI could regulate M. tuberculosis gene expression in vivo . Finally, there is a remarkable overlap between the RNI-inducible regulon and that previously reported to be regulated by hypoxia; and both reactive nitrogen species and anaerobicity upregulate the expression of one and the same putative twocomponent regulatory response system. Together, the results of this study provide evidence suggesting that (i) RNI play a role in regulating M. tuberculosis gene expression in vivo ; (ii) the reactive nitrogen species upregulate genes that may be conducive to the survival of the tubercle bacillus in the infected host; and (iii) RNI and hypoxia may regulate mycobacterial gene expression via overlapping signal transduction pathways.

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Mycobacterial Stationary Phase Induced by Low Oxygen Tension: Cell Wall Thickening and Localization of the 16-Kilodalton α-Crystallin Homolog

Cited by 328 publications

References 45 publications

Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP 16.3 and human αB‐crystallin

Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP 16.3 and human αB‐crystallin

Oxygen depletion induced dormancy in Mycobacterium smegmatis

The effects of reactive nitrogen intermediates on gene expression inMycobacterium tuberculosis

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