<named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence

ABSTRACT To survive a dynamic host environment, Mycobacterium tuberculosis must endure a series of challenges, from reactive oxygen and nitrogen stress to drastic shifts in oxygen availability. The mycobacterial Lsr2 protein has been implicated in reactive oxygen defense via direct protection of DNA...

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Autores principales: I. L. Bartek, L. K. Woolhiser, A. D. Baughn, R. J. Basaraba, W. R. Jacobs, A. J. Lenaerts, M. I. Voskuil
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Publicado: American Society for Microbiology 2014
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spelling oai:doaj.org-article:cf4ae209d7c846c69c8c3d6c7abac1422021-11-15T15:47:38Z<named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence10.1128/mBio.01106-142150-7511https://doaj.org/article/cf4ae209d7c846c69c8c3d6c7abac1422014-07-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01106-14https://doaj.org/toc/2150-7511ABSTRACT To survive a dynamic host environment, Mycobacterium tuberculosis must endure a series of challenges, from reactive oxygen and nitrogen stress to drastic shifts in oxygen availability. The mycobacterial Lsr2 protein has been implicated in reactive oxygen defense via direct protection of DNA. To examine the role of Lsr2 in pathogenesis and physiology of M. tuberculosis, we generated a strain deleted for lsr2. Analysis of the M. tuberculosis Δlsr2 strain demonstrated that Lsr2 is not required for DNA protection, as this strain was equally susceptible as the wild type to DNA-damaging agents. The lsr2 mutant did display severe growth defects under normoxic and hyperoxic conditions, but it was not required for growth under low-oxygen conditions. However, it was also required for adaptation to anaerobiosis. The defect in anaerobic adaptation led to a marked decrease in viability during anaerobiosis, as well as a lag in recovery from it. Gene expression profiling of the Δlsr2 mutant under aerobic and anaerobic conditions in conjunction with published DNA binding-site data indicates that Lsr2 is a global transcriptional regulator controlling adaptation to changing oxygen levels. The Δlsr2 strain was capable of establishing an early infection in the BALB/c mouse model; however, it was severely defective in persisting in the lungs and caused no discernible lung pathology. These findings demonstrate M. tuberculosis Lsr2 is a global transcriptional regulator required for control of genes involved in adaptation to extremes in oxygen availability and is required for persistent infection. IMPORTANCE M. tuberculosis causes nearly two million deaths per year and infects nearly one-third of the world population. The success of this aerobic pathogen is due in part to its ability to successfully adapt to constantly changing oxygen availability throughout the infectious cycle, from the high oxygen tension during aerosol transmission to anaerobiosis within necrotic lesions. An understanding of how M. tuberculosis copes with these changes in oxygen tension is critical for its eventual eradication. Using a mutation in lsr2, we demonstrate that the Lsr2 protein present in all mycobacteria is a global transcriptional regulator in control of genes required for adaptation to changes in oxygen levels. M. tuberculosis lacking lsr2 was unable to adapt to both high and very low levels of oxygen and was defective in long-term anaerobic survival. Lsr2 was also required for disease pathology and for chronic infection in a mouse model of TB.I. L. BartekL. K. WoolhiserA. D. BaughnR. J. BasarabaW. R. JacobsA. J. LenaertsM. I. VoskuilAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 5, Iss 3 (2014)
institution DOAJ
collection DOAJ
language EN
topic Microbiology
QR1-502
spellingShingle Microbiology
QR1-502
I. L. Bartek
L. K. Woolhiser
A. D. Baughn
R. J. Basaraba
W. R. Jacobs
A. J. Lenaerts
M. I. Voskuil
<named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
description ABSTRACT To survive a dynamic host environment, Mycobacterium tuberculosis must endure a series of challenges, from reactive oxygen and nitrogen stress to drastic shifts in oxygen availability. The mycobacterial Lsr2 protein has been implicated in reactive oxygen defense via direct protection of DNA. To examine the role of Lsr2 in pathogenesis and physiology of M. tuberculosis, we generated a strain deleted for lsr2. Analysis of the M. tuberculosis Δlsr2 strain demonstrated that Lsr2 is not required for DNA protection, as this strain was equally susceptible as the wild type to DNA-damaging agents. The lsr2 mutant did display severe growth defects under normoxic and hyperoxic conditions, but it was not required for growth under low-oxygen conditions. However, it was also required for adaptation to anaerobiosis. The defect in anaerobic adaptation led to a marked decrease in viability during anaerobiosis, as well as a lag in recovery from it. Gene expression profiling of the Δlsr2 mutant under aerobic and anaerobic conditions in conjunction with published DNA binding-site data indicates that Lsr2 is a global transcriptional regulator controlling adaptation to changing oxygen levels. The Δlsr2 strain was capable of establishing an early infection in the BALB/c mouse model; however, it was severely defective in persisting in the lungs and caused no discernible lung pathology. These findings demonstrate M. tuberculosis Lsr2 is a global transcriptional regulator required for control of genes involved in adaptation to extremes in oxygen availability and is required for persistent infection. IMPORTANCE M. tuberculosis causes nearly two million deaths per year and infects nearly one-third of the world population. The success of this aerobic pathogen is due in part to its ability to successfully adapt to constantly changing oxygen availability throughout the infectious cycle, from the high oxygen tension during aerosol transmission to anaerobiosis within necrotic lesions. An understanding of how M. tuberculosis copes with these changes in oxygen tension is critical for its eventual eradication. Using a mutation in lsr2, we demonstrate that the Lsr2 protein present in all mycobacteria is a global transcriptional regulator in control of genes required for adaptation to changes in oxygen levels. M. tuberculosis lacking lsr2 was unable to adapt to both high and very low levels of oxygen and was defective in long-term anaerobic survival. Lsr2 was also required for disease pathology and for chronic infection in a mouse model of TB.
format article
author I. L. Bartek
L. K. Woolhiser
A. D. Baughn
R. J. Basaraba
W. R. Jacobs
A. J. Lenaerts
M. I. Voskuil
author_facet I. L. Bartek
L. K. Woolhiser
A. D. Baughn
R. J. Basaraba
W. R. Jacobs
A. J. Lenaerts
M. I. Voskuil
author_sort I. L. Bartek
title <named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
title_short <named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
title_full <named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
title_fullStr <named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
title_full_unstemmed <named-content content-type="genus-species">Mycobacterium tuberculosis</named-content> Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence
title_sort <named-content content-type="genus-species">mycobacterium tuberculosis</named-content> lsr2 is a global transcriptional regulator required for adaptation to changing oxygen levels and virulence
publisher American Society for Microbiology
publishDate 2014
url https://doaj.org/article/cf4ae209d7c846c69c8c3d6c7abac142
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