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Duława-Kobeluszczyk J, Strzałka A, Tracz M, Bartyńska M, Pawlikiewicz K, Łebkowski T, Wróbel S, Szymczak J, Zarek A, Małecki T, Jakimowicz D, Szafran MJ. The activity of CobB1 protein deacetylase contributes to nucleoid compaction in Streptomyces venezuelae spores by increasing HupS affinity for DNA. Nucleic Acids Res 2024; 52:7112-7128. [PMID: 38783097 PMCID: PMC11229371 DOI: 10.1093/nar/gkae418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
Streptomyces are soil bacteria with complex life cycle. During sporulation Streptomyces linear chromosomes become highly compacted so that the genetic material fits within limited spore volume. The key players in this process are nucleoid-associated proteins (NAPs). Among them, HU (heat unstable) proteins are the most abundant NAPs in the cell and the most conserved in bacteria. HupS, one of the two HU homologues encoded by the Streptomyces genome, is the best-studied spore-associated NAP. In contrast to other HU homologues, HupS contains a long, C-terminal domain that is extremely rich in lysine repeats (LR domain) similar to eukaryotic histone H2B and mycobacterial HupB protein. Here, we have investigated, whether lysine residues in HupS are posttranslationally modified by reversible lysine acetylation. We have confirmed that Streptomyces venezuelae HupS is acetylated in vivo. We showed that HupS binding to DNA in vitro is controlled by the acetylation. Moreover, we identified that CobB1, one of two Sir2 homologues in Streptomyces, controls HupS acetylation levels in vivo. We demonstrate that the elimination of CobB1 increases HupS mobility, reduces chromosome compaction in spores, and affects spores maturation. Thus, our studies indicate that HupS acetylation affects its function by diminishing DNA binding and disturbing chromosome organization.
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Affiliation(s)
| | | | - Michał Tracz
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | | | | | - Tomasz Łebkowski
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | - Sara Wróbel
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | - Justyna Szymczak
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | - Anna Zarek
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | - Tomasz Małecki
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
| | | | - Marcin J Szafran
- Faculty of Biotechnology, University of Wrocław, 50-383 Wrocław, Poland
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2
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Santoshi M, Tare P, Nagaraja V. Nucleoid-associated proteins of mycobacteria come with a distinctive flavor. Mol Microbiol 2024. [PMID: 38922783 DOI: 10.1111/mmi.15287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024]
Abstract
In every bacterium, nucleoid-associated proteins (NAPs) play crucial roles in chromosome organization, replication, repair, gene expression, and other DNA transactions. Their central role in controlling the chromatin dynamics and transcription has been well-appreciated in several well-studied organisms. Here, we review the diversity, distribution, structure, and function of NAPs from the genus Mycobacterium. We highlight the progress made in our understanding of the effects of these proteins on various processes and in responding to environmental stimuli and stress of mycobacteria in their free-living as well as during distinctive intracellular lifestyles. We project them as potential drug targets and discuss future studies to bridge the information gap with NAPs from well-studied systems.
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Affiliation(s)
- Meghna Santoshi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Priyanka Tare
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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3
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Nishiyama A, Shimizu M, Narita T, Kodera N, Ozeki Y, Yokoyama A, Mayanagi K, Yamaguchi T, Hakamata M, Shaban A, Tateishi Y, Ito K, Matsumoto S. Dynamic action of an intrinsically disordered protein in DNA compaction that induces mycobacterial dormancy. Nucleic Acids Res 2024; 52:816-830. [PMID: 38048321 PMCID: PMC10810275 DOI: 10.1093/nar/gkad1149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 10/17/2023] [Accepted: 11/23/2023] [Indexed: 12/06/2023] Open
Abstract
Mycobacteria are the major human pathogens with the capacity to become dormant persisters. Mycobacterial DNA-binding protein 1 (MDP1), an abundant histone-like protein in dormant mycobacteria, induces dormancy phenotypes, e.g. chromosome compaction and growth suppression. For these functions, the polycationic intrinsically disordered region (IDR) is essential. However, the disordered property of IDR stands in the way of clarifying the molecular mechanism. Here we clarified the molecular and structural mechanism of DNA compaction by MDP1. Using high-speed atomic force microscopy, we observed that monomeric MDP1 bundles two adjacent DNA duplexes side-by-side via IDR. Combined with coarse-grained molecular dynamics simulation, we revealed the novel dynamic DNA cross-linking model of MDP1 in which a stretched IDR cross-links two DNA duplexes like double-sided tape. IDR is able to hijack HU function, resulting in the induction of strong mycobacterial growth arrest. This IDR-mediated reversible DNA cross-linking is a reasonable model for MDP1 suppression of the genomic function in the resuscitable non-replicating dormant mycobacteria.
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Affiliation(s)
- Akihito Nishiyama
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Masahiro Shimizu
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
- Division of Quantum Beam Material Science, Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2 Asashiro-Nishi, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - Tomoyuki Narita
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
| | - Noriyuki Kodera
- Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuriko Ozeki
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Akira Yokoyama
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Kouta Mayanagi
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takehiro Yamaguchi
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Pharmacology, Osaka Metropolitan University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan
| | - Mariko Hakamata
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Department of Respiratory Medicine and Infectious Disease, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Amina Kaboso Shaban
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Yoshitaka Tateishi
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
| | - Kosuke Ito
- Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Sohkichi Matsumoto
- Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata 951-8510, Japan
- Laboratory of Tuberculosis, Institute of Tropical Disease, Universitas Airlangga, Kampus C Jl. Mulyorejo, Surabaya, East Java 60115, Indonesia
- Division of Research Aids, Hokkaido University Institute for Vaccine Research & Development, Kita 20, Nishi 10, Kita-ku, Sapporo, 001-0020, Japan
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4
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Keshavam CC, Naz S, Gupta A, Sanyal P, Kochar M, Gangwal A, Sangwan N, Kumar N, Tyagi E, Goel S, Singh NK, Sowpati DT, Khare G, Ganguli M, Raze D, Locht C, Basu-Modak S, Gupta M, Nandicoori VK, Singh Y. The heparin-binding hemagglutinin protein of Mycobacterium tuberculosis is a nucleoid-associated protein. J Biol Chem 2023; 299:105364. [PMID: 37865319 PMCID: PMC10665949 DOI: 10.1016/j.jbc.2023.105364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/23/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) regulate multiple cellular processes such as gene expression, virulence, and dormancy throughout bacterial species. NAPs help in the survival and adaptation of Mycobacterium tuberculosis (Mtb) within the host. Fourteen NAPs have been identified in Escherichia coli; however, only seven NAPs are documented in Mtb. Given its complex lifestyle, it is reasonable to assume that Mtb would encode for more NAPs. Using bioinformatics tools and biochemical experiments, we have identified the heparin-binding hemagglutinin (HbhA) protein of Mtb as a novel sequence-independent DNA-binding protein which has previously been characterized as an adhesion molecule required for extrapulmonary dissemination. Deleting the carboxy-terminal domain of HbhA resulted in a complete loss of its DNA-binding activity. Atomic force microscopy showed HbhA-mediated architectural modulations in the DNA, which may play a regulatory role in transcription and genome organization. Our results showed that HbhA colocalizes with the nucleoid region of Mtb. Transcriptomics analyses of a hbhA KO strain revealed that it regulates the expression of ∼36% of total and ∼29% of essential genes. Deletion of hbhA resulted in the upregulation of ∼73% of all differentially expressed genes, belonging to multiple pathways suggesting it to be a global repressor. The results show that HbhA is a nonessential NAP regulating gene expression globally and acting as a plausible transcriptional repressor.
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Affiliation(s)
| | - Saba Naz
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Aanchal Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Priyadarshini Sanyal
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India
| | - Manisha Kochar
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Nitika Sangwan
- Department of Zoology, University of Delhi, Delhi, India
| | - Nishant Kumar
- Department of Zoology, University of Delhi, Delhi, India
| | - Ekta Tyagi
- Department of Zoology, University of Delhi, Delhi, India
| | - Simran Goel
- Department of Zoology, University of Delhi, Delhi, India
| | | | | | - Garima Khare
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Munia Ganguli
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Dominique Raze
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | - Camille Locht
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | | | - Meetu Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India.
| | - Vinay Kumar Nandicoori
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India; National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India.
| | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, India; Delhi School of Public Health, Institution of Eminence, University of Delhi, Delhi, India.
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5
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Hołówka J, Łebkowski T, Feddersen H, Giacomelli G, Drużka K, Makowski Ł, Trojanowski D, Broda N, Bramkamp M, Zakrzewska-Czerwińska J. Mycobacterial IHF is a highly dynamic nucleoid-associated protein that assists HupB in organizing chromatin. Front Microbiol 2023; 14:1146406. [PMID: 36960278 PMCID: PMC10028186 DOI: 10.3389/fmicb.2023.1146406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/20/2023] [Indexed: 03/09/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) crucially contribute to organizing bacterial chromatin and regulating gene expression. Among the most highly expressed NAPs are the HU and integration host factor (IHF) proteins, whose functional homologues, HupB and mycobacterial integration host factor (mIHF), are found in mycobacteria. Despite their importance for the pathogenicity and/or survival of tubercle bacilli, the role of these proteins in mycobacterial chromosome organization remains unknown. Here, we used various approaches, including super-resolution microscopy, to perform a comprehensive analysis of the roles of HupB and mIHF in chromosome organization. We report that HupB is a structural agent that maintains chromosome integrity on a local scale, and that the lack of this protein alters chromosome morphology. In contrast, mIHF is a highly dynamic protein that binds DNA only transiently, exhibits susceptibility to the chromosomal DNA topology changes and whose depletion leads to the growth arrest of tubercle bacilli. Additionally, we have shown that depletion of Mycobacterium smegmatis integration host factor (msIHF) leads to chromosome shrinkage and replication inhibition.
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Affiliation(s)
- Joanna Hołówka
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
- *Correspondence: Joanna Hołówka,
| | - Tomasz Łebkowski
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
| | - Helge Feddersen
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
| | - Giacomo Giacomelli
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
| | - Karolina Drużka
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
| | - Łukasz Makowski
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
| | - Damian Trojanowski
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
| | - Natalia Broda
- Department of Molecular Microbiology, University of Wrocław, Wrocław, Poland
| | - Marc Bramkamp
- Institute for General Microbiology, Christian-Albrechts-University, Kiel, Germany
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6
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Ohara Y, Ozeki Y, Tateishi Y, Mashima T, Arisaka F, Tsunaka Y, Fujiwara Y, Nishiyama A, Yoshida Y, Kitadokoro K, Kobayashi H, Kaneko Y, Nakagawa I, Maekura R, Yamamoto S, Katahira M, Matsumoto S. Significance of a histone-like protein with its native structure for the diagnosis of asymptomatic tuberculosis. PLoS One 2018; 13:e0204160. [PMID: 30359374 PMCID: PMC6201868 DOI: 10.1371/journal.pone.0204160] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 09/03/2018] [Indexed: 12/15/2022] Open
Abstract
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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Affiliation(s)
- Yukiko Ohara
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
- Department of Microbiology, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan
- * E-mail: (YOh); (YOz); (SM)
| | - Yuriko Ozeki
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
- * E-mail: (YOh); (YOz); (SM)
| | - Yoshitaka Tateishi
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Tsukasa Mashima
- Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, Japan
| | - Fumio Arisaka
- College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan
| | - Yasuo Tsunaka
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Japan
| | - Yoshie Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, Japan
| | - Akihito Nishiyama
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Yutaka Yoshida
- Department of Structural Pathology, Institute of Nephrology, Graduate School of Medicine, Niigata University, Niigata, Japan
| | - Kengo Kitadokoro
- Graduate School of Science and Technology, Department of Biomolecular Engineering, Kyoto Institute of Technology, Matsugasakigosyokaido-cho, Sakyo-ku, Kyoto, Japan
| | - Haruka Kobayashi
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Yukihiro Kaneko
- Department of Bacteriology and Virology, Osaka-City University Graduate School of Medicine, Osaka, Japan
| | - Ichiro Nakagawa
- Department of Microbiology, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan
| | - Ryoji Maekura
- Department of Respiratory Medicine, National Hospital Organization Toneyama National Hospital, 5-1-1 Toneyama, Toyonaka, Osaka, Japan
- Graduate School of Health Care Sciences, Jikei Institute, Osaka, Japan
| | - Saburo Yamamoto
- Central Laboratory, Japan BCG Laboratory, Kiyose-shi, Tokyo, Japan
| | - Masato Katahira
- Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, Japan
| | - Sohkichi Matsumoto
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
- * E-mail: (YOh); (YOz); (SM)
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7
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Kalra P, Mishra SK, Kaur S, Kumar A, Prasad HK, Sharma TK, Tyagi JS. G-Quadruplex-Forming DNA Aptamers Inhibit the DNA-Binding Function of HupB and Mycobacterium tuberculosis Entry into Host Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2018; 13:99-109. [PMID: 30245472 PMCID: PMC6148841 DOI: 10.1016/j.omtn.2018.08.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 01/26/2023]
Abstract
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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Affiliation(s)
- Priya Kalra
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Subodh Kumar Mishra
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Madhya Pradesh 453552, India
| | - Surinder Kaur
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India
| | - Amit Kumar
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Madhya Pradesh 453552, India
| | | | - Tarun Kumar Sharma
- Centre for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, Haryana 121001, India.
| | - Jaya Sivaswami Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, Delhi 110029, India; Centre for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, Haryana 121001, India.
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8
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C-terminal intrinsically disordered region-dependent organization of the mycobacterial genome by a histone-like protein. Sci Rep 2018; 8:8197. [PMID: 29844400 PMCID: PMC5974015 DOI: 10.1038/s41598-018-26463-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/11/2018] [Indexed: 11/23/2022] Open
Abstract
The architecture of the genome influences the functions of DNA from bacteria to eukaryotes. Intrinsically disordered regions (IDR) of eukaryotic histones have pivotal roles in various processes of gene expression. IDR is rare in bacteria, but interestingly, mycobacteria produce a unique histone-like protein, MDP1 that contains a long C-terminal IDR. Here we analyzed the role of IDR in MDP1 function. By employing Mycobacterium smegmatis that inducibly expresses MDP1 or its IDR-deficient mutant, we observed that MDP1 induces IDR-dependent DNA compaction. MDP1-IDR is also responsible for the induction of growth arrest and tolerance to isoniazid, a front line tuberculosis drug that kills growing but not growth-retardated mycobacteria. We demonstrated that MDP1-deficiency and conditional knock out of MDP1 cause spreading of the M. smegmatis genome in the stationary phase. This study thus demonstrates for the first time a C-terminal region-dependent organization of the genome architecture by MDP1, implying the significance of IDR in the function of bacterial histone-like protein.
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9
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The Origin of Chromosomal Replication Is Asymmetrically Positioned on the Mycobacterial Nucleoid, and the Timing of Its Firing Depends on HupB. J Bacteriol 2018. [PMID: 29531181 DOI: 10.1128/jb.00044-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The bacterial chromosome undergoes dynamic changes in response to ongoing cellular processes and adaptation to environmental conditions. Among the many proteins involved in maintaining this dynamism, the most abundant is the nucleoid-associated protein (NAP) HU. In mycobacteria, the HU homolog, HupB, possesses an additional C-terminal domain that resembles that of eukaryotic histones H1/H5. Recently, we demonstrated that the highly abundant HupB protein occupies the entirety of the Mycobacterium smegmatis chromosome and that the HupB-binding sites exhibit a bias from the origin (oriC) to the terminus (ter). In this study, we used HupB fused with enhanced green fluorescent protein (EGFP) to perform the first analysis of chromosome dynamics and to track the oriC and replication machinery directly on the chromosome during the mycobacterial cell cycle. We show that the chromosome is located in an off-center position that reflects the unequal division and growth of mycobacterial cells. Moreover, unlike the situation in E. coli, the sister oriC regions of M. smegmatis move asymmetrically along the mycobacterial nucleoid. Interestingly, in this slow-growing organism, the initiation of the next round of replication precedes the physical separation of sister chromosomes. Finally, we show that HupB is involved in the precise timing of replication initiation.IMPORTANCE Although our view of mycobacterial nucleoid organization has evolved considerably over time, we still know little about the dynamics of the mycobacterial nucleoid during the cell cycle. HupB is a highly abundant mycobacterial nucleoid-associated protein (NAP) with an indispensable histone-like tail. It was previously suggested as a potential target for antibiotic therapy against tuberculosis. Here, we fused HupB with enhanced green fluorescent protein (EGFP) to study the dynamics of the mycobacterial chromosome in real time and to monitor the replication process directly on the chromosome. Our results reveal that, unlike the situation in Escherichia coli, the nucleoid of an apically growing mycobacterium is positioned asymmetrically within the cell throughout the cell cycle. We show that HupB is involved in controlling the timing of replication initiation. Since tuberculosis remains a serious health problem, studies concerning mycobacterial cell biology are of great importance.
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10
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Kriel NL, Gallant J, van Wyk N, van Helden P, Sampson SL, Warren RM, Williams MJ. Mycobacterial nucleoid associated proteins: An added dimension in gene regulation. Tuberculosis (Edinb) 2018. [DOI: 10.1016/j.tube.2017.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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Abstract
In bacteria, chromosomal DNA must be efficiently compacted to fit inside the small cell compartment while remaining available for the proteins involved in replication, segregation, and transcription. Among the nucleoid-associated proteins (NAPs) responsible for maintaining this highly organized and yet dynamic chromosome structure, the HU protein is one of the most conserved and highly abundant. HupB, a homologue of HU, was recently identified in mycobacteria. This intriguing mycobacterial NAP is composed of two domains: an N-terminal domain that resembles bacterial HU, and a long and distinctive C-terminal domain that contains several PAKK/KAAK motifs, which are characteristic of the H1/H5 family of eukaryotic histones. In this study, we analyzed the in vivo binding of HupB on the chromosome scale. By using PALM (photoactivated localization microscopy) and ChIP-Seq (chromatin immunoprecipitation followed by deep sequencing), we observed that the C-terminal domain is indispensable for the association of HupB with the nucleoid. Strikingly, the in vivo binding of HupB displayed a bias from the origin (oriC) to the terminus (ter) of the mycobacterial chromosome (numbers of binding sites decreased toward ter). We hypothesized that this binding mode reflects a role for HupB in organizing newly replicated oriC regions. Thus, HupB may be involved in coordinating replication with chromosome segregation.IMPORTANCE We currently know little about the organization of the mycobacterial chromosome and its dynamics during the cell cycle. Among the mycobacterial nucleoid-associated proteins (NAPs) responsible for chromosome organization and dynamics, HupB is one of the most intriguing. It contains a long and distinctive C-terminal domain that harbors several PAKK/KAAK motifs, which are characteristic of the eukaryotic histone H1/H5 proteins. The HupB protein is also known to be crucial for the survival of tubercle bacilli during infection. Here, we provide in vivo experimental evidence showing that the C-terminal domain of HupB is crucial for its DNA binding. Our results suggest that HupB may be involved in organizing newly replicated regions and could help coordinate chromosome replication with segregation. Given that tuberculosis (TB) remains a serious worldwide health problem (10.4 million new TB cases were diagnosed in 2015, according to WHO) and new multidrug-resistant Mycobacterium tuberculosis strains are continually emerging, further studies of the biological function of HupB are needed to determine if this protein could be a prospect for novel antimicrobial drug development.
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Defining the Functionally Important Domain and Amino Acid Residues in Mycobacterium tuberculosis Integration Host Factor for Genome Stability, DNA Binding, and Integrative Recombination. J Bacteriol 2017; 199:JB.00357-17. [PMID: 28696279 DOI: 10.1128/jb.00357-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/25/2017] [Indexed: 11/20/2022] Open
Abstract
The integration host factor of Mycobacterium tuberculosis (mIHF) consists of a single polypeptide chain, the product of the ihf gene. We previously revealed that mIHF is a novel member of a new class of nucleoid-associated proteins that have important roles in DNA damage response, nucleoid compaction, and integrative recombination. The mIHF contains a region of 86 amino acids at its N terminus, absent from both α- and β-subunits of Escherichia coli IHF. However, the functional significance of an extra 86-amino-acid region in the full-length protein remains unknown. Here, we report the structure/function relationship of the DNA-binding and integrative recombination-stimulating activity of mIHF. Deletion mutagenesis showed that an extra 86-amino-acid region at the N terminus is dispensable; the C-terminal region possesses the sequences essential for its known biological functions, including the ability to suppress the sensitivity of E. coli ΔihfA and ΔihfB cells to DNA-damaging agents, DNA binding, DNA multimerization-circularization, and stimulation of phage L5 integrase-catalyzed integrative recombination. Single and double alanine substitutions at positions Arg170 and Arg171, located at the mIHF DNA-binding site, abrogated its capacity to suppress the sensitivity of E. coli ΔihfA and ΔihfB cells to DNA-damaging agents. The variants encoded by these mutant alleles failed to bind DNA and stimulate integrative recombination. Interestingly, the DNA-binding activity of the mIHF-R173A variant remained largely unaffected; however, it was unable to stimulate integrative recombination, thus revealing a separation-of-function allele of mIHF. The functional and structural characterization of this separation-of-function allele of mIHF could reveal previously unknown functions of IHF.IMPORTANCE The integration host factor of Mycobacterium tuberculosis is a novel nucleoid-associated protein. mIHF plays a vital role in DNA damage response, nucleoid compaction, and integrative recombination. Intriguingly, mIHF contains an extra 86-amino-acid region at its N terminus, absent from both α- and β-subunits of Escherichia coli IHF, whose functional significance is unknown. Furthermore, a triad of arginine residues located at the mIHF-DNA interface have been implicated in a range of its functions. Here, we reveal the roles of N- and C-terminal regions of mIHF and the individual residues in the Arg triad for their ability to provide protection in vivo against DNA damage, bind DNA, and stimulate integrase-catalyzed site-specific recombination.
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13
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Liu Z, Gao Y, Yang H, Bao H, Qin L, Zhu C, Chen Y, Hu Z. Impact of Hypoxia on Drug Resistance and Growth Characteristics of Mycobacterium tuberculosis Clinical Isolates. PLoS One 2016; 11:e0166052. [PMID: 27835653 PMCID: PMC5106006 DOI: 10.1371/journal.pone.0166052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/11/2016] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis (MTB) is a specific aerobic bacterium, but can survive under hypoxic conditions, such as those in lung cheese necrosis, granulomas, or macrophages. It is not clear whether the drug sensitivity and growth characteristics of MTB under hypoxic conditions are different from those under aerobic conditions. In this study, we examined the drug resistance and growth characteristics of MTB clinical isolates by a large sample of in vitro drug susceptibility tests, using an automatic growth instrument. Under hypoxic conditions, variance in drug resistance was observed in nearly one-third of the MTB strains and was defined as MTB strains with changed drug sensitivity (MTB-CDS). Among these strains, resistance in a considerable proportion of clinical strains was significantly increased, and some strains emerged as multi-drug resistant. Growth test results revealed a high growth rate and large survival number in macrophages under hypoxia in MTB-CDS. According to the results of fluorescence quantitative PCR, the expression of some genes, including RegX3 (involving RIF resistance), Rv0194 (efflux pump gene), four genes related to transcription regulation (KstR, DosR, Rv0081 and WhiB3) and gene related to translation regulation (DATIN), were upregulated significantly under hypoxic conditions compared to that under aerobic conditions (p < 0.05). Thus, we concluded that some MTB clinical isolates can survive under hypoxic conditions and their resistance could change. As for poor clinical outcomes in patients, based on routine drug susceptibility testing, drug susceptibility tests for tuberculosis under hypoxic conditions should also be recommended. However, the detailed mechanisms of the effect of hypoxia on drug sensitivity and growth characteristics of MTB clinical isolates still requires further study.
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Affiliation(s)
- Zhonghua Liu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yulu Gao
- Department of Laboratory Medicine, Kunshan Hospital Affiliated to Nanjing University of Traditional Chinese Medicine, Kunshan, China
| | - Hua Yang
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haiyang Bao
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lianhua Qin
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Changtai Zhu
- Department of Transfusion, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- * E-mail: (CTZ); (YWC); (ZYH)
| | - Yawen Chen
- Department of Nursing, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- * E-mail: (CTZ); (YWC); (ZYH)
| | - Zhongyi Hu
- Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
- * E-mail: (CTZ); (YWC); (ZYH)
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14
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Bouthier de la Tour C, Blanchard L, Dulermo R, Ludanyi M, Devigne A, Armengaud J, Sommer S, de Groot A. The abundant and essential HU proteins in Deinococcus deserti and Deinococcus radiodurans are translated from leaderless mRNA. MICROBIOLOGY-SGM 2015; 161:2410-22. [PMID: 26385459 DOI: 10.1099/mic.0.000186] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
HU proteins have an important architectural role in nucleoid organization in bacteria. Compared with HU of many bacteria, HU proteins from Deinococcus species possess an N-terminal lysine-rich extension similar to the eukaryotic histone H1 C-terminal domain involved in DNA compaction. The single HU gene in Deinococcus radiodurans, encoding DrHU, is required for nucleoid compaction and cell viability. Deinococcus deserti contains three expressed HU genes, encoding DdHU1, DdHU2 and DdHU3. Here, we show that either DdHU1 or DdHU2 is essential in D. deserti. DdHU1 and DdHU2, but not DdHU3, can substitute for DrHU in D. radiodurans, indicating that DdHU3 may have a non-essential function different from DdHU1, DdHU2 and DrHU. Interestingly, the highly abundant DrHU and DdHU1 proteins, and also the less expressed DdHU2, are translated in Deinococcus from leaderless mRNAs, which lack a 5'-untranslated region and, hence, the Shine-Dalgarno sequence. Unexpectedly, cloning the DrHU or DdHU1 gene under control of a strong promoter in an expression plasmid, which results in leadered transcripts, strongly reduced the DrHU and DdHU1 protein level in D. radiodurans compared with that obtained from the natural leaderless gene. We also show that the start codon position for DrHU and DdHU1 should be reannotated, resulting in proteins that are 15 and 4 aa residues shorter than initially reported. The expression level and start codon correction were crucial for functional characterization of HU in Deinococcus.
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Affiliation(s)
- Claire Bouthier de la Tour
- 1Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France
| | - Laurence Blanchard
- 2CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 3CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France
| | - Rémi Dulermo
- 1Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France 3CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France 5CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem, F-13108 Saint-Paul-lez-Durance, France
| | - Monika Ludanyi
- 2CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 3CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 4Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France
| | - Alice Devigne
- 1Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France
| | - Jean Armengaud
- 6CEA-Marcoule, DSV/IBITEC-S/SPI/Li2D, Laboratory 'Innovative technologies for Detection and Diagnostic', BP 17171, F-30207 Bagnols-sur-Cèze, France
| | - Suzanne Sommer
- 1Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Bâtiment 409, F-91405 Orsay, France
| | - Arjan de Groot
- 3CNRS, UMR 7265 Biol Veget & Microbiol Environ, F-13108 Saint-Paul-lez-Durance, France 2CEA, DSV, IBEB, Lab Bioenerget Cellulaire, F-13108 Saint-Paul-lez-Durance, France 4Aix-Marseille Université, F-13108 Saint-Paul-lez-Durance, France
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15
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Suvorova IA, Korostelev YD, Gelfand MS. GntR Family of Bacterial Transcription Factors and Their DNA Binding Motifs: Structure, Positioning and Co-Evolution. PLoS One 2015; 10:e0132618. [PMID: 26151451 PMCID: PMC4494728 DOI: 10.1371/journal.pone.0132618] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/16/2015] [Indexed: 12/03/2022] Open
Abstract
The GntR family of transcription factors (TFs) is a large group of proteins present in diverse bacteria and regulating various biological processes. Here we use the comparative genomics approach to reconstruct regulons and identify binding motifs of regulators from three subfamilies of the GntR family, FadR, HutC, and YtrA. Using these data, we attempt to predict DNA-protein contacts by analyzing correlations between binding motifs in DNA and amino acid sequences of TFs. We identify pairs of positions with high correlation between amino acids and nucleotides for FadR, HutC, and YtrA subfamilies and show that the most predicted DNA-protein interactions are quite similar in all subfamilies and conform well to the experimentally identified contacts formed by FadR from E. coli and AraR from B. subtilis. The most frequent predicted contacts in the analyzed subfamilies are Arg-G, Asn-A, Asp-C. We also analyze the divergon structure and preferred site positions relative to regulated genes in the FadR and HutC subfamilies. A single site in a divergon usually regulates both operons and is approximately in the middle of the intergenic area. Double sites are either involved in the co-operative regulation of both operons and then are in the center of the intergenic area, or each site in the pair independently regulates its own operon and tends to be near it. We also identify additional candidate TF-binding boxes near palindromic binding sites of TFs from the FadR, HutC, and YtrA subfamilies, which may play role in the binding of additional TF-subunits.
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Affiliation(s)
- Inna A. Suvorova
- Research and Training Center on Bioinformatics, Institute for Information Transmission Problems RAS (The Kharkevich Institute), Moscow, Russia
- * E-mail:
| | - Yuri D. Korostelev
- Research and Training Center on Bioinformatics, Institute for Information Transmission Problems RAS (The Kharkevich Institute), Moscow, Russia
| | - Mikhail S. Gelfand
- Research and Training Center on Bioinformatics, Institute for Information Transmission Problems RAS (The Kharkevich Institute), Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
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16
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Sharadamma N, Harshavardhana Y, Ravishankar A, Anand P, Chandra N, Muniyappa K. Molecular Dissection of Mycobacterium tuberculosis Integration Host Factor Reveals Novel Insights into the Mode of DNA Binding and Nucleoid Compaction. Biochemistry 2015; 54:4142-60. [DOI: 10.1021/acs.biochem.5b00447] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Apoorva Ravishankar
- Department of
Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Praveen Anand
- Department of
Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Nagasuma Chandra
- Department of
Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - K. Muniyappa
- Department of
Biochemistry, Indian Institute of Science, Bangalore 560012, India
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17
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Knapp GS, Lyubetskaya A, Peterson MW, Gomes ALC, Ma Z, Galagan JE, McDonough KA. Role of intragenic binding of cAMP responsive protein (CRP) in regulation of the succinate dehydrogenase genes Rv0249c-Rv0247c in TB complex mycobacteria. Nucleic Acids Res 2015; 43:5377-93. [PMID: 25940627 PMCID: PMC4477654 DOI: 10.1093/nar/gkv420] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/19/2015] [Indexed: 11/14/2022] Open
Abstract
Bacterial pathogens adapt to changing environments within their hosts, and the signaling molecule adenosine 3', 5'-cyclic monophosphate (cAMP) facilitates this process. In this study, we characterized in vivo DNA binding and gene regulation by the cAMP-responsive protein CRP in M. bovis BCG as a model for tuberculosis (TB)-complex bacteria. Chromatin immunoprecipitation followed by deep-sequencing (ChIP-seq) showed that CRP associates with ∼900 DNA binding regions, most of which occur within genes. The most highly enriched binding region was upstream of a putative copper transporter gene (ctpB), and crp-deleted bacteria showed increased sensitivity to copper toxicity. Detailed mutational analysis of four CRP binding sites upstream of the virulence-associated Rv0249c-Rv0247c succinate dehydrogenase genes demonstrated that CRP directly regulates Rv0249c-Rv0247c expression from two promoters, one of which requires sequences intragenic to Rv0250c for maximum expression. The high percentage of intragenic CRP binding sites and our demonstration that these intragenic DNA sequences significantly contribute to biologically relevant gene expression greatly expand the genome space that must be considered for gene regulatory analyses in mycobacteria. These findings also have practical implications for an important bacterial pathogen in which identification of mutations that affect expression of drug target-related genes is widely used for rapid drug resistance screening.
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Affiliation(s)
- Gwendowlyn S Knapp
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| | - Anna Lyubetskaya
- Bioinformatics Program, Boston University, Boston, MA 02215, USA
| | | | | | - Zhuo Ma
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| | - James E Galagan
- Bioinformatics Program, Boston University, Boston, MA 02215, USA Department of Biomedical Engineering, Boston, MA 02215, USA Department of Microbiology, Boston University, Boston, MA 02215, USA
| | - Kathleen A McDonough
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12201, USA
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18
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Sharadamma N, Harshavardhana Y, Ravishankar A, Anand P, Chandra N, Muniyappa K. Molecular dissection of Mycobacterium tuberculosis integration host factor reveals novel insights into the mode of DNA binding and nucleoid compaction. J Biol Chem 2014; 289:34325-40. [PMID: 25324543 DOI: 10.1074/jbc.m114.608596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The annotated whole-genome sequence of Mycobacterium tuberculosis revealed that Rv1388 (Mtihf) is likely to encode for a putative 20-kDa integration host factor (mIHF). However, very little is known about the functional properties of mIHF or the organization of the mycobacterial nucleoid. Molecular modeling of the mIHF three-dimensional structure, based on the cocrystal structure of Streptomyces coelicolor IHF duplex DNA, a bona fide relative of mIHF, revealed the presence of Arg-170, Arg-171, and Arg-173, which might be involved in DNA binding, and a conserved proline (Pro-150) in the tight turn. The phenotypic sensitivity of Escherichia coli ΔihfA and ΔihfB strains to UV and methyl methanesulfonate could be complemented with the wild-type Mtihf but not its alleles bearing mutations in the DNA-binding residues. Protein-DNA interaction assays revealed that wild-type mIHF, but not its DNA-binding variants, binds with high affinity to fragments containing attB and attP sites and curved DNA. Strikingly, the functionally important amino acid residues of mIHF and the mechanism(s) underlying its binding to DNA, DNA bending, and site-specific recombination are fundamentally different from that of E. coli IHFαβ. Furthermore, we reveal novel insights into IHF-mediated DNA compaction depending on the placement of its preferred binding sites; mIHF promotes DNA compaction into nucleoid-like or higher order filamentous structures. We therefore propose that mIHF is a distinct member of a subfamily of proteins that serve as essential cofactors in site-specific recombination and nucleoid organization and that these findings represent a significant advance in our understanding of the role(s) of nucleoid-associated proteins.
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Affiliation(s)
| | | | - Apoorva Ravishankar
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Praveen Anand
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Nagasuma Chandra
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - K Muniyappa
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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19
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Pandey SD, Choudhury M, Sritharan M. Transcriptional regulation of Mycobacterium tuberculosis hupB gene expression. MICROBIOLOGY-SGM 2014; 160:1637-1647. [PMID: 24858079 DOI: 10.1099/mic.0.079640-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The influence of iron levels on the transcription of the hupB gene in Mycobacterium tuberculosis is the focus of this study. Studies in our laboratory showed HupB to be co-expressed with the two siderophores in low-iron organisms. Mycobactin biosynthesis is repressed by the IdeR-Fe(2+) complex that binds the IdeR box in the mbtB promoter. Recently, we demonstrated the positive regulatory effect of HupB on mycobactin biosynthesis by demonstrating its binding to a 10 bp HupB box in the mbtB promoter. Earlier, we observed that HupB, expressed maximally in low-iron media (0.02 µg Fe ml(-1); 0.36 µM Fe) was still detectable at 8 µg Fe ml(-1) (144 µM Fe) when the siderophores were absent and complete repression was seen only at 12 µg Fe ml(-1) (216 µM Fe). In this study, we observed elevated levels of hupB transcripts in iron-limited organisms. IdeR, and not FurA, functioned as the iron regulator, by binding to two IdeR boxes in the hupB promoter. Interestingly, the 10 bp HupB box, first reported in the mbtB promoter, was identified in the hupB promoter. Using DNA footprinting and electrophoretic mobility shift assays, we demonstrated the functionality of the HupB box and the two IdeR boxes. The high hupB transcript levels expressed by the organism and the in vitro protein-DNA interaction studies led us to hypothesize the sequence of events occurring in response to changes in the intracellular iron concentration, emphasizing the roles played by IdeR and HupB in iron homeostasis.
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Affiliation(s)
- Satya Deo Pandey
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
| | - Mitali Choudhury
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
| | - Manjula Sritharan
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao Road, Gachibowli, Hyderabad 500046, India
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20
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HupB, a nucleoid-associated protein of Mycobacterium tuberculosis, is modified by serine/threonine protein kinases in vivo. J Bacteriol 2014; 196:2646-57. [PMID: 24816602 DOI: 10.1128/jb.01625-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HU, a widely conserved bacterial histone-like protein, regulates many genes, including those involved in stress response and virulence. Whereas ample data are available on HU-DNA communication, the knowledge on how HU perceives a signal and transmit it to DNA remains limited. In this study, we identify HupB, the HU homolog of the human pathogen Mycobacterium tuberculosis, as a component of serine/threonine protein kinase (STPK) signaling. HupB is extracted in its native state from the exponentially growing cells of M. tuberculosis H37Ra and is shown to be phosphorylated on both serine and threonine residues. The STPKs capable of modifying HupB are determined in vitro and the residues modified by the STPKs are identified for both in vivo and the in vitro proteins through mass spectrometry. Of the identified phosphosites, Thr(65) and Thr(74) in the DNA-embracing β-strand of the N-terminal domain of HupB (N-HupB) are shown to be crucial for its interaction with DNA. In addition, Arg(55) is also identified as an important residue for N-HupB-DNA interaction. N-HupB is shown to have a diminished interaction with DNA after phosphorylation. Furthermore, hupB is shown to be maximally expressed during the stationary phase in M. tuberculosis H37Ra, while HupB kinases were found to be constitutively expressed (PknE and PknF) or most abundant during the exponential phase (PknB). In conclusion, HupB, a DNA-binding protein, with an ability to modulate chromatin structure is proposed to work in a growth-phase-dependent manner through its phosphorylation carried out by the mycobacterial STPKs.
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