Transcriptional regulation of Mycobacterium tuberculosis hupB gene expression

Pandey, Satya Deo; Choudhury, Mitali; Sritharan, Manjula

doi:10.1099/mic.0.079640-0

Cited by 18 publications

(18 citation statements)

References 25 publications

(56 reference statements)

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“…tuberculosis [ 2 , 12 ]. The expression of MDP1 can be triggered by an iron deficiency[ 13 , 14 ], which mimics intracellular environments. These reports suggest that individuals with asymptomatic tuberculosis have substantial levels of MDP1 expression.…”

Section: Introductionmentioning

confidence: 99%

Significance of a histone-like protein with its native structure for the diagnosis of asymptomatic tuberculosis

Ohara¹,

Ozeki²,

Tateishi³

et al. 2018

PLoS ONE

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Tuberculosis causes the highest mortality among all single infections. Asymptomatic tuberculosis, afflicting one third of the global human population, is the major source as 5–10% of asymptomatic cases develop active tuberculosis during their lifetime. Thus it is one of important issues to develop diagnostic tools for accurately detecting asymptomatic infection. Mycobacterial DNA-binding protein 1 (MDP1) is a major protein in persistent Mycobacterium tuberculosis and has potential for diagnostic use in detecting asymptomatic infection. However, a previous ELISA-based study revealed a specificity problem; IgGs against MDP1 were detected in both M. tuberculosis-infected and uninfected individuals. Although the tertiary structures of an antigen are known to influence antibody recognition, the MDP1 structural details have not yet been investigated. The N-terminal half of MDP1, homologous to bacterial histone-like protein HU, is predicted to be responsible for DNA-binding, while the C-terminal half is assumed as totally intrinsically disordered regions. To clarify the relationship between the MDP1 tertiary structure and IgG recognition, we refined the purification method, which allow us to obtain a recombinant protein with the predicted structure. Furthermore, we showed that an IgG-ELISA using MDP1 purified by our refined method is indeed useful in the detection of asymptomatic tuberculosis.

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Section: Introductionmentioning

confidence: 99%

Significance of a histone-like protein with its native structure for the diagnosis of asymptomatic tuberculosis

Ohara¹,

Ozeki²,

Tateishi³

et al. 2018

PLoS ONE

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“…Although, mycobacterial HupB protein shows strong interaction with various forms of DNA (linear, repair, replication intermediates, etc.) in a sequence-independent manner, 5 , 40 it specifically displays superior binding affinity to an ∼10-bp DNA motif designated as “HupB-box.” 41 We observed significantly reduced interaction between HupB and narK2 promoter DNA (5′-biotinylated), in presence of increasing amounts of unlabeled HupB-4T and HupB-13T aptamers ( Figure 5 A). This observation appeared at first to be somewhat counterintuitive, considering that the aptamer-binding site likely mapped in the CTD of HupB, whereas NTD of HupB was assigned the dsDNA-binding function.…”

Section: Resultsmentioning

confidence: 81%

G-Quadruplex-Forming DNA Aptamers Inhibit the DNA-Binding Function of HupB and Mycobacterium tuberculosis Entry into Host Cells

Kalra

Mishra

Kaur

et al. 2018

Molecular Therapy - Nucleic Acids

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The entry and survival of Mycobacterium tuberculosis (Mtb) within host cells is orchestrated partly by an essential histone-like protein HupB (Rv2986c). Despite being an essential drug target, the lack of structural information has impeded the development of inhibitors targeting the indispensable and multifunctional C-terminal domain (CTD) of HupB. To bypass the requirement for structural information in the classical drug discovery route, we generated a panel of DNA aptamers against HupB protein through systemic evolution of ligands by exponential (SELEX) enrichment. Two G-quadruplex-forming high-affinity aptamers (HupB-4T and HupB-13T) were identified, each of which bound two distinct sites on full-length HupB, with an estimated KD of ∼1.72 μM and ∼0.17 μM, respectively, for the high-affinity sites. While HupB-4T robustly inhibited DNA-binding activity of HupB in vitro, both the aptamers recognized surface-located HupB and significantly blocked Mtb entry into THP-1 monocytic cells (p < 0.0001). In summary, DNA aptamers generated in this study block DNA-binding activity of HupB, inhibit virulent Mtb infection in host cells, and demonstrate aptamers to be inhibitors of HupB functions. This study also illustrates the utility of SELEX in developing inhibitors against essential targets for whom structural information is not available.

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“…The association of HupB with iron metabolism in M. tuberculosis was first demonstrated by Yeruva and coworkers, who identified the protein as a 28-kDa cell wall-associated protein in organisms (14) grown in iron-limiting medium (0.02 g Fe ml Ϫ1 ; 0.36 M Fe). Under high-iron conditions, hupB transcription is repressed by the IdeR-Fe 2ϩ complex, as seen from its interaction with the two IdeR boxes located at positions Ϫ5 and Ϫ127 upstream of hupB (43).…”

Section: Transcriptional Regulation Of Mycobactin Biosynthesis: Role mentioning

confidence: 99%

Iron Homeostasis in Mycobacterium tuberculosis: Mechanistic Insights into Siderophore-Mediated Iron Uptake

2016

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Mycobacterium tuberculosis requires iron for normal growth but faces a limitation of the metal ion due to its low solubility at biological pH and the withholding of iron by the mammalian host. The pathogen expresses the Fe 3؉ -specific siderophores mycobactin and carboxymycobactin to chelate the metal ion from insoluble iron and the host proteins transferrin, lactoferrin, and ferritin. Siderophore-mediated iron uptake is essential for the survival of M. tuberculosis, as knockout mutants, which were defective in siderophore synthesis or uptake, failed to survive in low-iron medium and inside macrophages. But as excess iron is toxic due to its catalytic role in the generation of free radicals, regulation of iron uptake is necessary to maintain optimal levels of intracellular iron. The focus of this review is to present a comprehensive overview of iron homeostasis in M. tuberculosis that is discussed in the context of mycobactin biosynthesis, transport of iron across the mycobacterial cell envelope, and storage of excess iron. The clinical significance of the serum iron status and the expression of the iron-regulated protein HupB in tuberculosis (TB) patients is presented here, highlighting the potential of HupB as a marker, notably in extrapulmonary TB cases.

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Transcriptional regulation of Mycobacterium tuberculosis hupB gene expression

Cited by 18 publications

References 25 publications

Significance of a histone-like protein with its native structure for the diagnosis of asymptomatic tuberculosis

Significance of a histone-like protein with its native structure for the diagnosis of asymptomatic tuberculosis

G-Quadruplex-Forming DNA Aptamers Inhibit the DNA-Binding Function of HupB and Mycobacterium tuberculosis Entry into Host Cells

Iron Homeostasis in Mycobacterium tuberculosis: Mechanistic Insights into Siderophore-Mediated Iron Uptake

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