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Jiang Q, Hu R, Liu F, Huang F, Zhang L, Zhang H. Characterization of a Novel Oxidative Stress Responsive Transcription Regulator in Mycobacterium bovis. Biomedicines 2024; 12:1872. [PMID: 39200336 PMCID: PMC11351531 DOI: 10.3390/biomedicines12081872] [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: 07/28/2024] [Accepted: 08/14/2024] [Indexed: 09/02/2024] Open
Abstract
The antioxidant defense is critical for the survival of intracellular pathogens such as Mycobacterium tuberculosis complex (MTBC) species, including Mycobacterium bovis, which are often exposed to an oxidative environment caused by reactive oxygen species (ROS) in hosts. However, the signaling pathway in mycobacteria for sensing and responding to oxidative stress remains largely unclear. In this study, we characterize a TetR-type transcription regulator BCG_3893c, designated AotM, as a novel redox sensor in Mycobacterium bovis that increases mycobacterial tolerance to oxidative stress. AotM is required for the growth of M. bovis in the presence of 1 mM hydrogen peroxide. Loss of the aotM gene leads to altered transcriptional profiles with 352 genes significantly up-regulated and 25 genes significantly down-regulated. AotM recognizes a 14-bp palindrome sequence motif and negatively regulates the expression of a FAD-dependent oxidoreductase encoded by bcg_3892c. Overexpression of BCG_3892c increases intracellular ROS production and reduces the growth of M. bovis. In summary, we propose that AotM enhances the mycobacterial resistance against oxidative stress probably by inhibiting intracellular ROS production. Our findings reveal a novel underlying regulatory mechanism behind mycobacterial oxidative stress adaptation.
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Affiliation(s)
- Qiang Jiang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Rong Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Feng Liu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Feng Huang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Lei Zhang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Hua Zhang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
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Zhu C, Wei WP, An JN, Hu JL, Gao CH, Yang M. SdrR, a LysR-type regulator, responds to the mycobacterial antioxidant defense. J Biochem 2024; 176:43-54. [PMID: 38444151 DOI: 10.1093/jb/mvae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/26/2024] [Accepted: 02/27/2024] [Indexed: 03/07/2024] Open
Abstract
Protection against oxidative stress is a vital defense mechanism for Mycobacterium tuberculosis within the host. However, few transcription factors that control bacterial antioxidant defense are known. Here, we present evidence that SdrR, encoded by the MSMEG_5712 (Ms5712) gene, functions as an oxidative stress response regulator in Mycobacterium smegmatis. SdrR recognizes an 11-bp motif sequence in the operon's upstream regulatory region and negatively regulates the expression of short-chain dehydrogenases/reductases (SDR). Overexpressing sdrR inhibited SDR expression, which rendered the strain oxidative more stress-sensitive. Conversely, sdrR knockout alleviates SDR repression, which increases its oxidative stress tolerance. Thus, SdrR responds to oxidative stress by negatively regulating sdr expression. Therefore, this study elucidated an underlying regulatory mechanism behind mycobacterial oxidative stress adaptation.
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Affiliation(s)
- Chen Zhu
- School of Basic Medicine, Guizhou University of Traditional Chinese Medicine, Guiyang, 550025, China
| | - Wen-Ping Wei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jing-Ning An
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jia-Ling Hu
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chun-Hui Gao
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Min Yang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
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Wang C, Yang J, Xu Z, Lv L, Chen S, Hong M, Liu JH. Promoter regulatory mode evolution enhances the high multidrug resistance of tmexCD1-toprJ1. mBio 2024; 15:e0021824. [PMID: 38564664 PMCID: PMC11077950 DOI: 10.1128/mbio.00218-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/10/2024] [Indexed: 04/04/2024] Open
Abstract
Antibiotic resistance could rapidly emerge from acquiring the mobile antibiotic resistance genes, which are commonly evolved from an intrinsic gene. The emergence of the plasmid-borne mobilized efflux pump gene cluster tmexCD1-toprJ1 renders the last-resort antibiotic tigecycline ineffective, although its evolutionary mechanism remains unclear. In this study, we investigate the regulatory mechanisms of the progenitor NfxB-MexCD-OprJ, a chromosomally encoded operon that does not mediate antibiotic resistance in the wild-type version, and its homologs, TNfxB1-TMexCD1-TOprJ1 mediating high-level tigecycline resistance, and TNfxB3-TMexCD3-TOprJ1. Mechanistic studies demonstrated that in nfxB-mexCD-oprJ, MexCD expression was under a weaker promoter, PmexC and inhibited by a strong repressor NfxB. For tmexCD1-toprJ1, TMexCD1 was highly expressed owing to the presence of a strong promoter, PtmexC1, and an inactive suppressor, TNfxB1, with a T39R mutation that rendered it unable to bind to promoter DNA. In tnfxB3-tmexCD3-toprJ1b, TMexCD3 expression was intermediate because of the local regulator TNfxB3, which binds to two inverted repeat sequences of PtmexC. Additionally, TNfxB3 exhibited lower protein expression and weaker DNA binding affinity than its ancestor NfxB, together with their promoter activities difference explaining the different expression levels of tmexCD-toprJ homologs. Distinct fitness burdens on these homologs-carrying bacteria were observed due to the corresponding expression level, which might be associated with their global prevalence. In summary, our data depict the mechanisms underlying the evolution and dissemination of an important mobile antibiotic resistance gene from an intrinsic chromosomal gene.IMPORTANCEAs antibiotic resistance seriously challenges global health, tigecycline is one of the few effective drugs in the pipeline against infections caused by multidrug-resistant pathogens. Our previous work identified a novel tigecycline resistance efflux pump gene cluster tmexCD1-toprJ1 in animals and humans, together with its various variants, a rising clinical concern. Herein, this study focused on how the local regulation modes of tmexCD1-toprJ1 evolved to a highly expressed efflux pump. Through comparative analysis between three tnfxB-tmexCD-toprJ homologs and their progenitor nfxB-mexCD-oprJ, modes, we demonstrated the evolutionary dynamics from a chromosomal silent gene to an active state. We found the de-repression of the local regulator and an increase of the promoter activity work together to promote a high production of drug efflux machines and enhance multidrug resistance. Our findings revealed that TMexCD1-TOprJ1 adopts a distinct evolutionary path to achieve higher multidrug resistance, urgently needing tight surveillance.
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Affiliation(s)
- Chengzhen Wang
- State Key Laboratory for Animal Disease Control and Prevention, Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou, Guangdong, China
| | - Jun Yang
- State Key Laboratory for Animal Disease Control and Prevention, Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou, Guangdong, China
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Luchao Lv
- State Key Laboratory for Animal Disease Control and Prevention, Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou, Guangdong, China
| | - Sheng Chen
- State Key Lab of Chemical Biology and Drug Discovery and the Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Mei Hong
- College of Life Sciences, South China Agricultural University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Guangzhou, China
| | - Jian-Hua Liu
- State Key Laboratory for Animal Disease Control and Prevention, Guangdong Laboratory for Lingnan Modern Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Zoonosis of Ministry of Agricultural and Rural Affairs, National Risk Assessment Laboratory for Antimicrobial Resistant of Microorganisms in Animals, Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, Guangzhou, Guangdong, China
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Li Y, Wei Y, Guo X, Li X, Lu L, Hu L, He Z. Insertion sequence transposition activates antimycobacteriophage immunity through an lsr2-silenced lipid metabolism gene island. MLIFE 2024; 3:87-100. [PMID: 38827510 PMCID: PMC11139207 DOI: 10.1002/mlf2.12106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/16/2024] [Accepted: 01/26/2024] [Indexed: 06/04/2024]
Abstract
Insertion sequences (ISs) exist widely in bacterial genomes, but their roles in the evolution of bacterial antiphage defense remain to be clarified. Here, we report that, under the pressure of phage infection, the IS1096 transposition of Mycobacterium smegmatis into the lsr2 gene can occur at high frequencies, which endows the mutant mycobacterium with a broad-spectrum antiphage ability. Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related genes. The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium, thus defending against phage infection. Strikingly, a phage that has evolved mutations in two tail-filament genes can re-escape from the lsr2 inactivation-triggered host defense. This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by IS transposition and provided insight into the natural evolution of bacterial antiphage defense.
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Affiliation(s)
- Yakun Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Yuyun Wei
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Xiao Guo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Xiaohui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Lining Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Lihua Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
| | - Zheng‐Guo He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and TechnologyGuangxi UniversityNanningChina
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Ling X, Liu X, Wang K, Guo M, Ou Y, Li D, Xiang Y, Zheng J, Hu L, Zhang H, Li W. Lsr2 acts as a cyclic di-GMP receptor that promotes keto-mycolic acid synthesis and biofilm formation in mycobacteria. Nat Commun 2024; 15:695. [PMID: 38267428 PMCID: PMC10808224 DOI: 10.1038/s41467-024-44774-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 01/03/2024] [Indexed: 01/26/2024] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a second messenger that promotes biofilm formation in several bacterial species, but the mechanisms are often unclear. Here, we report that c-di-GMP promotes biofilm formation in mycobacteria in a manner dependent on the nucleoid-associated protein Lsr2. We show that c-di-GMP specifically binds to Lsr2 at a ratio of 1:1. Lsr2 upregulates the expression of HadD, a (3R)-hydroxyacyl-ACP dehydratase, thus promoting the synthesis of keto-mycolic acid and biofilm formation. Thus, Lsr2 acts as a c-di-GMP receptor that links the second messenger's function to lipid synthesis and biofilm formation in mycobacteria.
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Affiliation(s)
- Xiaocui Ling
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Xiao Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Kun Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Minhao Guo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Yanzhe Ou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Danting Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Yulin Xiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Jiachen Zheng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Lihua Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Hongyun Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, 530004, China.
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6
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Li X, Long X, Chen L, Guo X, Lu L, Hu L, He ZG. Mycobacterial phage TM4 requires a eukaryotic-like Ser/Thr protein kinase to silence and escape anti-phage immunity. Cell Host Microbe 2023; 31:1469-1480.e4. [PMID: 37567169 DOI: 10.1016/j.chom.2023.07.005] [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: 01/23/2023] [Revised: 05/15/2023] [Accepted: 07/14/2023] [Indexed: 08/13/2023]
Abstract
In eukaryotic cells, serine/threonine protein kinases (StpKs) play important roles in limiting viral infections. StpKs are commonly activated upon infections, inhibiting the expression of genes central for viral replication. Here, we report that a eukaryotic-like StpK7 encoded by MSMEG_1200 in M. smegmatis is required for mycobacteriophage TM4 to escape bacterial defense. stpK7 is located within a gene island, MSMEG_1191-MSMEG_1200, containing multiple anti-phage genes resembling the BREX (bacteriophage exclusion) phage-resistance system. StpK7 negatively regulates the expression of this gene island. Following phage TM4 infection, StpK7 is induced, directly phosphorylating the transcriptional regulator MSMEG_1198 and inhibiting its positive regulatory activity, thus reducing the expression of multiple downstream genes in the BREX-like gene island. Further analysis showed that genes within this anti-phage island critically regulate mycobacterial lipid hemostasis and phage adsorption. Collectively, this work characterizes a regulatory network driven by StpK7, which is utilized by phage TM4 to escape from the host defense against mycobacteria.
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Affiliation(s)
- Xiaohui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Xiating Long
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Liu Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Xiao Guo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Lining Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Lihua Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Zheng-Guo He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
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Wang H, Wang X, Tang Q, Wang L, Mei C, Shao Y, Xu Y, Lu Z, Zhong W. Regulation Mechanism of Nicotine Catabolism in Sphingomonas melonis TY by a Dual Role Transcriptional Regulator NdpR. Appl Environ Microbiol 2023; 89:e0032423. [PMID: 37071026 PMCID: PMC10231238 DOI: 10.1128/aem.00324-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 03/25/2023] [Indexed: 04/19/2023] Open
Abstract
A gene cluster ndp, responsible for nicotine degradation via a variant of the pyridine and pyrrolidine pathways, was previously identified in Sphingomonas melonis TY, but the regulation mechanism remains unknown. The gene ndpR within the cluster was predicted to encode a TetR family transcriptional regulator. Deletion of ndpR resulted in a notably shorter lag phase, higher maximum turbidity, and faster substrate degradation when cultivated in the presence of nicotine. Real-time quantitative PCR and promoter activity analysis in wild-type TY and TYΔndpR strains revealed that genes in the ndp cluster were negatively regulated by NdpR. However, complementation of ndpR to TYΔndpR did not restore transcription repression, but, instead, the complemented strain showed better growth than TYΔndpR. Promoter activity analysis indicates that NdpR also functions as an activator in the transcription regulation of ndpHFEGD. Further analysis through electrophoretic mobility shift assay and DNase I footprinting assay revealed that NdpR binds five DNA sequences within ndp and that NdpR has no autoregulation. These binding motifs overlap with the -35 or -10 box or are located distal upstream of the corresponding transcriptional start site. Multiple sequence alignment of these five NdpR-binding DNA sequences found a conserved motif, with two of the binding sequences being partially palindromic. 2,5-Dihydroxypyridine acted as a ligand of NdpR, preventing NdpR from binding to the promoter region of ndpASAL, ndpTB, and ndpHFEGD. This study revealed that NdpR binds to three promoters in the ndp cluster and is a dual-role transcriptional regulator in nicotine metabolism. IMPORTANCE Gene regulation is critical for microorganisms in the environment in which they may encounter various kinds of organic pollutants. Our study revealed that transcription of ndpASAL, ndpTB, and ndpHFEGD is negatively regulated by NdpR, and NdpR also exhibits a positive regulatory effect on PndpHFEGD. Furthermore, 2,5-dihydroxypyridine was identified as the effector molecular for NdpR and can both prevent the binding of free NdpR to the promoter and release NdpR from the promoters, which is different from previously reported NicR2. Additionally, NdpR was found to have both negative and positive transcription regulatory effects on the same target, PndpHFEGD, while only one binding site was identified, which is notably different from the previously reported TetR family regulators. Moreover, NdpR was revealed to be a global transcriptional regulator. This study provides new insight into the complex gene expression regulation of the TetR family.
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Affiliation(s)
- Haixia Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xiaoyu Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Qi Tang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Lvjing Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Chengyu Mei
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yunhai Shao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Ying Xu
- Department of Microbial Sciences, State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhenmei Lu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Weihong Zhong
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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Dupuy P, Ghosh S, Fay A, Adefisayo O, Gupta R, Shuman S, Glickman MS. Roles for mycobacterial DinB2 in frameshift and substitution mutagenesis. eLife 2023; 12:e83094. [PMID: 37141254 PMCID: PMC10159617 DOI: 10.7554/elife.83094] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 04/18/2023] [Indexed: 05/05/2023] Open
Abstract
Translesion synthesis by translesion polymerases is a conserved mechanism of DNA damage tolerance. In bacteria, DinB enzymes are the widely distributed promutagenic translesion polymerases. The role of DinBs in mycobacterial mutagenesis was unclear until recent studies revealed a role for mycobacterial DinB1 in substitution and frameshift mutagenesis, overlapping with that of translesion polymerase DnaE2. Mycobacterium smegmatis encodes two additional DinBs (DinB2 and DinB3) and Mycobacterium tuberculosis encodes DinB2, but the roles of these polymerases in mycobacterial damage tolerance and mutagenesis is unknown. The biochemical properties of DinB2, including facile utilization of ribonucleotides and 8-oxo-guanine, suggest that DinB2 could be a promutagenic polymerase. Here, we examine the effects of DinB2 and DinB3 overexpression in mycobacterial cells. We demonstrate that DinB2 can drive diverse substitution mutations conferring antibiotic resistance. DinB2 induces frameshift mutations in homopolymeric sequences, both in vitro and in vivo. DinB2 switches from less to more mutagenic in the presence of manganese in vitro. This study indicates that DinB2 may contribute to mycobacterial mutagenesis and antibiotic resistance acquisition in combination with DinB1 and DnaE2.
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Affiliation(s)
- Pierre Dupuy
- Immunology Program, Sloan Kettering InstituteNew YorkUnited States
| | - Shreya Ghosh
- Molecular Biology Program, Sloan Kettering InstituteNew YorkUnited States
| | - Allison Fay
- Immunology Program, Sloan Kettering InstituteNew YorkUnited States
| | - Oyindamola Adefisayo
- Immunology Program, Sloan Kettering InstituteNew YorkUnited States
- Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate SchoolNew YorkUnited States
| | - Richa Gupta
- Immunology Program, Sloan Kettering InstituteNew YorkUnited States
| | - Stewart Shuman
- Molecular Biology Program, Sloan Kettering InstituteNew YorkUnited States
| | - Michael S Glickman
- Immunology Program, Sloan Kettering InstituteNew YorkUnited States
- Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate SchoolNew YorkUnited States
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Wang K, Cui X, Ling X, Chen J, Zheng J, Xiang Y, Li W. D-Xylose Blocks the Broad Negative Regulation of XylR on Lipid Metabolism and Affects Multiple Physiological Characteristics in Mycobacteria. Int J Mol Sci 2023; 24:ijms24087086. [PMID: 37108247 PMCID: PMC10138657 DOI: 10.3390/ijms24087086] [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: 03/17/2023] [Revised: 04/01/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
D-xylose is the most abundant fermentable pentose, which usually represents an architectural component of the bacterial cell wall. However, its regulatory function and the involved signaling pathway in bacteria remain largely unclear. Here, we show that D-xylose can act as a signaling molecule to regulate the lipid metabolism and affect multiple physiological characteristics in mycobacteria. D-xylose directly interacts with XylR and inhibits its DNA-binding ability, thus blocking XylR-mediated repression. The xylose inhibitor, XylR, plays a global regulatory role and affects the expression of 166 mycobacterial genes that are involved in lipid synthesis and metabolism. Furthermore, we show that the xylose-dependent gene regulation of XylR affects the multiple physiological characteristics of Mycobacterium smegmatis, including bacterial size, colony phenotype, biofilm formation, cell aggregation, and antibiotic resistance. Finally, we found that XylR inhibited the survival of Mycobacterium bovis BCG in the host. Our findings provide novel insights into the molecular mechanism of lipid metabolism regulation and its correlation with bacterial physiological phenotypes.
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Affiliation(s)
- Kun Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Xujie Cui
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Xiaocui Ling
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Jiarui Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Jiachen Zheng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Yuling Xiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China
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10
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Wei W, Jiang X, Zhang L, Yan Y, Yan J, Xu L, Gao CH, Yang M. Regulation of CRISPR-Associated Genes by Rv1776c (CasR) in Mycobacterium tuberculosis. Biomolecules 2023; 13:biom13020400. [PMID: 36830769 PMCID: PMC9953421 DOI: 10.3390/biom13020400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/07/2023] [Accepted: 02/18/2023] [Indexed: 02/23/2023] Open
Abstract
The CRISPR-Cas system is an adaptive immune system for many bacteria and archaea to defend against foreign nucleic acid invasion, and this system is conserved in the genome of M. tuberculosis (Mtb). Although the CRISPR-Cas system-mediated immune defense mechanism has been revealed in Mtb, the regulation of cas gene expression is poorly understood. In this study, we identified a transcription factor, CasR (CRISPR-associated protein repressor, encoded by Rv1776c), and it could bind to the upstream DNA sequence of the CRISPR-Cas gene cluster and regulate the expression of cas genes. EMSA and ChIP assays confirmed that CasR could interact with the upstream sequence of the csm6 promoter, both in vivo and in vitro. Furthermore, DNA footprinting assay revealed that CasR recognized a 20 bp palindromic sequence motif and negatively regulated the expression of csm6. In conclusion, our research elucidates the regulatory effect of CasR on the expression of CRISPR-associated genes in mycobacteria, thus providing insight into gene expression regulation of the CRISPR-Cas system.
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Affiliation(s)
- Wenping Wei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaofang Jiang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Li Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yunjun Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Correspondence: (Y.Y.); (M.Y.)
| | - Jinyong Yan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Li Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Chun-Hui Gao
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Min Yang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Correspondence: (Y.Y.); (M.Y.)
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11
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Wei W, Qiao J, Jiang X, Cai L, Hu X, He J, Chen M, Yang M, Cui T. Dehydroquinate Synthase Directly Binds to Streptomycin and Regulates Susceptibility of Mycobacterium bovis to Streptomycin in a Non-canonical Mode. Front Microbiol 2022; 13:818881. [PMID: 35516432 PMCID: PMC9063660 DOI: 10.3389/fmicb.2022.818881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/22/2022] [Indexed: 12/02/2022] Open
Abstract
Antimicrobial resistance (AMR) represents one of the main challenges in Tuberculosis (TB) treatment. Investigating the genes involved in AMR and the underlying mechanisms holds promise for developing alternative treatment strategies. The results indicate that dehydroquinate synthase (DHQS) regulates the susceptibility of Mycobacterium bovis BCG to first-line anti-TB drug streptomycin. Perturbation of the expression of aroB encoding DHQS affects the susceptibility of M. bovis BCG to streptomycin. Purified DHQS impairs in vitro antibacterial activity of streptomycin, but did not hydrolyze or modify streptomycin. DHQS directly binds to streptomycin while retaining its own catalytic activity. Computationally modeled structure analysis of DHQS–streptomycin complex reveals that DHQS binds to streptomycin without disturbing native substrate binding. In addition, streptomycin treatment significantly induces the expression of DHQS, thus resulting in DHQS-mediated susceptibility. Our findings uncover the additional function of DHQS in AMR and provide an insight into a non-canonical resistance mechanism by which protein hijacks antibiotic to reduce the interaction between antibiotic and its target with normal protein function retained.
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Affiliation(s)
- Wenping Wei
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Junjie Qiao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaofang Jiang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Luxia Cai
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaomin Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jin He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Min Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Min Yang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Min Yang,
| | - Tao Cui
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, China
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
- Tao Cui,
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12
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Li X, Chen F, Liu X, Xiao J, Andongma BT, Tang Q, Cao X, Chou SH, Galperin MY, He J. Clp protease and antisense RNA jointly regulate the global regulator CarD to mediate mycobacterial starvation response. eLife 2022; 11:73347. [PMID: 35080493 PMCID: PMC8820732 DOI: 10.7554/elife.73347] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/25/2022] [Indexed: 12/02/2022] Open
Abstract
Under starvation conditions, bacteria tend to slow down their translation rate by reducing rRNA synthesis, but the way they accomplish that may vary in different bacteria. In Mycobacterium species, transcription of rRNA is activated by the RNA polymerase (RNAP) accessory transcription factor CarD, which interacts directly with RNAP to stabilize the RNAP-promoter open complex formed on rRNA genes. The functions of CarD have been extensively studied, but the mechanisms that control its expression remain obscure. Here, we report that the level of CarD was tightly regulated when mycobacterial cells switched from nutrient-rich to nutrient-deprived conditions. At the translational level, an antisense RNA of carD (AscarD) was induced in a SigF-dependent manner to bind with carD mRNA and inhibit CarD translation, while at the post-translational level, the residual intracellular CarD was quickly degraded by the Clp protease. AscarD thus worked synergistically with Clp protease to decrease the CarD level to help mycobacterial cells cope with the nutritional stress. Altogether, our work elucidates the regulation mode of CarD and delineates a new mechanism for the mycobacterial starvation response, which is important for the adaptation and persistence of mycobacterial pathogens in the host environment.
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Affiliation(s)
- Xinfeng Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fang Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaoyu Liu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jinfeng Xiao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Binda T Andongma
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qing Tang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaojian Cao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, United States
| | - Jin He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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13
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Yan S, Zhen J, Li Y, Huang Y, Ai X, Li Y, Stojkoska A, Huang X, Ruan C, Li J, Fan L, Xie J. Mycobacterium Lrp/AsnC family transcriptional factor modulates the arginase pathway as both a sensor and a transcriptional repressor. J Genet Genomics 2021; 48:1020-1031. [PMID: 34696992 DOI: 10.1016/j.jgg.2021.06.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 12/26/2022]
Abstract
L-Arginine is the precursor of nitric oxide (NO), a host immune effector against intracellular pathogens including Mycobacterium tuberculosis (M. tb). Pathogens including M. tb have evolved various strategies targeting arginine to block the production of NO for better survival and proliferation. However, L-arginine metabolism and regulation in Mycobacterium are poorly understood. Here, we report the identification of M. smegmatis MSMEG_1415 (homolog of M. tb Rv2324) as an arginine-responsive transcriptional factor regulating the arginase pathway. In the absence of L-arginine, MSMEG_1415 acts as a repressor to inhibit the transcription of the roc (for arginine, ornithine catabolism) gene cluster, thereby switching off the arginase pathway. Treatment with L-arginine relieves the transcriptional inhibition of MSMEG_1415 on the roc gene cluster to activate the arginase pathway. Moreover, the L-arginine-MSMEG_1415 complex activates the transcription of the roc gene cluster by recognizing and binding a 15-bp palindrome motif, thereby preventing the excess accumulation of L-arginine in M. smegmatis. Physiologically, MSMEG_1415 confers mycobacteria resistance to starvation and fluoroquinolones exposure, suggestive of its important role in M. smegmatis persistence. The results uncover a unique regulatory mechanism of arginine metabolism in mycobacteria and identify M. tb Rv2324 as an attractive candidate target for the design of drugs against tuberculosis.
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Affiliation(s)
- Shuangquan Yan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Junfeng Zhen
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yuzhu Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yu Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xuefeng Ai
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yue Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Andrea Stojkoska
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xue Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Cao Ruan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jiang Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Lin Fan
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai Key Laboratory of Tuberculosis, Shanghai 200433, China.
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China.
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14
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Yang M, Jia SH, Tao HL, Zhu C, Jia WZ, Hu LH, Gao CH. Cd(II)-binding transcriptional regulator interacts with isoniazid and regulates drug susceptibility in mycobacteria. J Biochem 2021; 169:43-53. [PMID: 32706888 DOI: 10.1093/jb/mvaa086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 07/16/2020] [Indexed: 02/03/2023] Open
Abstract
It is urgent to understand the regulatory mechanism of drug resistance in widespread bacterial pathogens. In Mycobacterium tuberculosis, several transcriptional regulators have been found to play essential roles in regulating its drug resistance. In this study, we found that an ArsR family transcription regulator encoded by Rv2642 (CdiR) responds to isoniazid (INH), a widely used anti-tuberculosis (TB) drug. CdiR negatively regulates self and adjacent genes, including arsC (arsenic-transport integral membrane protein ArsC). CdiR directly interacts with INH and Cd(II). The binding of INH and Cd(II) both reduce its DNA-binding activity. Disrupting cdiR increased the drug susceptibility to INH, whereas overexpressing cdiR decreased the susceptibility. Strikingly, overexpressing arsC increased the drug susceptibility as well as cdiR. Additionally, both changes in cdiR and arsC expression caused sensitivity to other drugs such as rifamycin and ethambutol, where the minimal inhibitory concentrations in the cdiR deletion strain were equal to those of the arsC-overexpressing strain, suggesting that the function of CdiR in regulating drug resistance primarily depends on arsC. Furthermore, we found that Cd(II) enhances bacterial resistance to INH in a CdiR-dependent manner. As a conclusion, CdiR has a critical role in directing the interplay between Cd(II) metal ions and drug susceptibility in mycobacteria.
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Affiliation(s)
- Min Yang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shi-Hua Jia
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui-Ling Tao
- International Agricultural Institute, Yunnan Academy of Agricultural Sciences, Kunming 650224, China
| | - Chen Zhu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wan-Zhong Jia
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Li-Hua Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chun-Hui Gao
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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15
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Chen J, Zhang A, Xiang Z, Lu M, Huang P, Gong T, Pan Y, Lin Y, Zhou X, Li Y. EpsR Negatively Regulates Streptococcus mutans Exopolysaccharide Synthesis. J Dent Res 2021; 100:968-976. [PMID: 33749354 DOI: 10.1177/00220345211000668] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans is considered the primary etiological agent of human dental caries. Glucosyltransferases (Gtfs) from S. mutans play important roles in the formation of biofilm matrix and the development of cariogenic oral biofilm. Therefore, Gtfs are considered an important target to prevent the development of dental caries. However, the role of transcription factors in regulating gtf expression is not yet clear. Here, we identify a MarR (multiple antibiotic resistance regulator) family transcription factor named EpsR (exopolysaccharide synthesis regulator), which negatively regulates gtfB expression and exopolysaccharide (EPS) production in S. mutans. The epsR in-frame deletion strain grew slowly, aggregated more easily in the presence of dextran, and displayed different colony morphology and biofilm structure. Notably, epsR deletion resulted in altered 3-dimensional biofilm architecture, increased water-insoluble EPS production, and upregulated GtfB protein content and activity. In addition, global gene expression profiling revealed differences in the expression levels of 69 genes in which gtfB was markedly upregulated. The conserved DNA motif for EpsR binding was determined by electrophoretic mobility shift assay and DNase I footprinting assays. Moreover, analysis of β-galactosidase activity suggested that EpsR acted as a repressor and inhibited gtfB expression. Taken together, our findings indicate that EpsR is an important transcription factor that regulates gtfB expression and EPS production in S. mutans. These results add new aspects to the complexity of regulating the expression of genes involved in the cariogenicity of S. mutans, which might lead to novel strategies to prevent the formation of cariogenic biofilm that may favor diseases.
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Affiliation(s)
- J Chen
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - A Zhang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Z Xiang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - M Lu
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P Huang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T Gong
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Pan
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Lin
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Zhou
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Li
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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16
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Li X, Chen L, Liao J, Hui J, Li W, He ZG. A novel stress-inducible CmtR-ESX3-Zn 2+ regulatory pathway essential for survival of Mycobacterium bovis under oxidative stress. J Biol Chem 2020; 295:17083-17099. [PMID: 33033071 PMCID: PMC7863910 DOI: 10.1074/jbc.ra120.013017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 09/28/2020] [Indexed: 11/06/2022] Open
Abstract
Reactive oxygen species (ROS) are an unavoidable host environmental cue for intracellular pathogens such as Mycobacterium tuberculosis and Mycobacterium bovis; however, the signaling pathway in mycobacteria for sensing and responding to environmental stress remains largely unclear. Here, we characterize a novel CmtR-Zur-ESX3-Zn2+ regulatory pathway in M. bovis that aids mycobacterial survival under oxidative stress. We demonstrate that CmtR functions as a novel redox sensor and that its expression can be significantly induced under H2O2 stress. CmtR can physically interact with the negative regulator Zur and de-represses the expression of the esx-3 operon, which leads to Zn2+ accumulation and promotion of reactive oxygen species detoxication in mycobacterial cells. Zn2+ can also act as an effector molecule of the CmtR regulator, using which the latter can de-repress its own expression for further inducing bacterial antioxidant adaptation. Consistently, CmtR can induce the expression of EsxH, a component of esx-3 operon involved in Zn2+ transportation that has been reported earlier, and inhibit phagosome maturation in macrophages. Lastly, CmtR significantly contributes to bacterial survival in macrophages and in the lungs of infected mice. Our findings reveal the existence of an antioxidant regulatory pathway in mycobacteria and provide novel information on stress-triggered gene regulation and its association with host-pathogen interaction.
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Affiliation(s)
- Xiaohui Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Liu Chen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jingjing Liao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiechen Hui
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Zheng-Guo He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, China.
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17
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Xu H, Su Z, Li W, Deng Y, He ZG. MmbR, a master transcription regulator that controls fatty acid β-oxidation genes in Mycolicibacterium smegmatis. Environ Microbiol 2020; 23:1096-1114. [PMID: 32985741 DOI: 10.1111/1462-2920.15249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/23/2020] [Indexed: 11/29/2022]
Abstract
An unusually high lipid content and a complex lipid profile are the most distinctive features of the mycobacterial cell envelope. However, our understanding of the regulatory mechanism underlying mycobacterial lipid metabolism is limited, and the major regulators responsible for lipid homeostasis remain to be characterized. Here, we identified MmbR as a novel master regulator that is essential for maintaining lipid homeostasis in Mycolicibacterium smegmatis. We found that MmbR controls fatty acid β-oxidation and modulates biofilm formation in Mycolicibacterium smegmatis. Although MmbR possesses the properties of nucleoid-associated proteins, it acts as a TetR-like transcription factor, directly regulating and intensively repressing the expression of a group of core genes involved in fatty acid β-oxidation. Furthermore, both long-chain acyl-Coenzyme A and fatty acids appear to regulate the signal molecules modulated by MmbR. The deletion of mmbR led to a significant reduction in intracellular fatty acid content and a decrease in the relative lipid composition of the biofilm. The lack of mmbR led to morphological changes in the mycobacterial colony, defects in biofilm formation and enhanced sensitivity to anti-tuberculosis drugs. Our study is the first to establish a link between the transcriptional regulation of fatty acid β-oxidation genes and lipid homeostasis in mycobacteria.
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Affiliation(s)
- Hui Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhi Su
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Weihui Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yimin Deng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zheng-Guo He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning, China
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18
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Yang M, Zhang L, Tao HL, Sun YC, Lou ZZ, Jia WZ, Hu LH, Gao CH. OxiR specifically responds to isoniazid and regulates isoniazid susceptibility in mycobacteria. FEMS Microbiol Lett 2020; 366:5498298. [PMID: 31125044 DOI: 10.1093/femsle/fnz109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 05/23/2019] [Indexed: 02/06/2023] Open
Abstract
The bacteria drug resistance is not only associated with the gain of drug resistance gene but also relied on the adaptation of bacterial cells to antibiotics by transcriptional regulation. However, only a few transcription factors that regulate drug resistance have been characterized in mycobacteria. In this study, a TetR family transcriptional factor (OxiR), encoded by Rv0067c in Mycobacterium tuberculosis, was found to be an isoniazid (INH) resistance regulator. Comparing with the wild-type strain, the oxiR overexpressing strain is four times resistant to INH, whereas the oxiR knockout strain is eight times sensitive to INH. However, the rifamycin and ethambutol resistance were not influenced by oxiR. OxiR can bind to self-promoter at a 66 bp imperfect palindromic motifs. Interestingly, OxiR directly binds to INH, and thereby alleviate the self-repression. Furthermore, OxiR negatively regulated an oxidoreductase encoded by Rv0068. And the susceptibility of the Rv0068-overexpressing and oxiR knockout strains to all the three above-mentioned anti-tuberculosis drugs was equivalent, suggesting that the effect of oxiR to INH susceptibility is attributed to the derepression of Rv0068. In conclusion, we showed that OxiR can specifically modulate INH susceptibility by regulating an oxidoreductase encoding gene, both of which have not been associated with drug-resistance previously.
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Affiliation(s)
- Min Yang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Road, Hongshan District, Wuhan, China (430070)
| | - Li Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Road, Hongshan District, Wuhan, China (430070)
| | - Hui-Ling Tao
- International Agricultural Institute, Yunnan Academy of Agricultural Sciences, No. 2338, Beijing China Road, Panlong District, Kunming, China (650000)
| | - Yuan-Chao Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Road, Hongshan District, Wuhan, China (430070)
| | - Zhong-Zi Lou
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1, Xujiaping, Chengguan District, Lanzhou, China (730046)
| | - Wan-Zhong Jia
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1, Xujiaping, Chengguan District, Lanzhou, China (730046)
| | - Li-Hua Hu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Road, Hongshan District, Wuhan, China (430070)
| | - Chun-Hui Gao
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, No. 1, Shizishan Road, Hongshan District, Wuhan, China (430070)
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19
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Hu J, Jin K, He ZG, Zhang H. Citrate lyase CitE in Mycobacterium tuberculosis contributes to mycobacterial survival under hypoxic conditions. PLoS One 2020; 15:e0230786. [PMID: 32302313 PMCID: PMC7164622 DOI: 10.1371/journal.pone.0230786] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 03/08/2020] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium tuberculosis is the causative agent of tuberculosis and has evolved an ability to survive in hostile host environments. M. tuberculosis is thought to utilize the rTCA cycle to sustain its latent growth during infection, but the enzymatic characteristics and physiological function for the key citrate lyase of the rTCA cycle, MtbCitE, in the important pathogen remain unclear. In this study, we investigated the function of MtbCitE based on its structural properties and sequence comparisons with other bacterial citrate lyase subunits. We showed that several amino acid residues were important for the citrate cleavage activity of MtbCitE. Strikingly, the citrate cleavage activity of MtbCitE was inhibited by ATP, indicating that energy metabolism might couple with the regulation of MtbCitE activity, which differed from other CitEs. More interestingly, deletion of citE from Mycobacterium bovis BCG decreased the mycobacterial survival rate under hypoxic conditions, whereas complementation with citE restored the phenotype to wild-type levels. Consistently, three key rTCA cycle enzymes were positively regulated under hypoxic conditions in mycobacteria. Therefore, we characterized a unique citrate lyase MtbCitE from M. tuberculosis and found that the CitE protein significantly contributed to mycobacterial survival under hypoxic conditions.
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Affiliation(s)
- Jialing Hu
- College of Life Science and Technology, National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Kaixi Jin
- College of Life Science and Technology, National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zheng-Guo He
- College of Life Science and Technology, National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Hua Zhang
- College of Life Science and Technology, National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- * E-mail:
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20
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Gao R, Wei W, Hassan BH, Li J, Deng J, Feng Y. A single regulator NrtR controls bacterial NAD + homeostasis via its acetylation. eLife 2019; 8:51603. [PMID: 31596237 PMCID: PMC6800001 DOI: 10.7554/elife.51603] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/04/2019] [Indexed: 12/27/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an indispensable cofactor in all domains of life, and its homeostasis must be regulated tightly. Here we report that a Nudix-related transcriptional factor, designated MsNrtR (MSMEG_3198), controls the de novo pathway of NAD+biosynthesis in M. smegmatis, a non-tuberculosis Mycobacterium. The integrated evidence in vitro and in vivo confirms that MsNrtR is an auto-repressor, which negatively controls the de novo NAD+biosynthetic pathway. Binding of MsNrtR cognate DNA is finely mapped, and can be disrupted by an ADP-ribose intermediate. Unexpectedly, we discover that the acetylation of MsNrtR at Lysine 134 participates in the homeostasis of intra-cellular NAD+ level in M. smegmatis. Furthermore, we demonstrate that NrtR acetylation proceeds via the non-enzymatic acetyl-phosphate (AcP) route rather than by the enzymatic Pat/CobB pathway. In addition, the acetylation also occurs on the paralogs of NrtR in the Gram-positive bacterium Streptococcus and the Gram-negative bacterium Vibrio, suggesting that these proteins have a common mechanism of post-translational modification in the context of NAD+ homeostasis. Together, these findings provide a first paradigm for the recruitment of acetylated NrtR to regulate bacterial central NAD+ metabolism.
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Affiliation(s)
- Rongsui Gao
- Department of Pathogen Biology & Microbiology, and Department General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenhui Wei
- Department of Pathogen Biology & Microbiology, and Department General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | | | - Jun Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jiaoyu Deng
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Youjun Feng
- Department of Pathogen Biology & Microbiology, and Department General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,College of Animal Sciences, Zhejiang University, Hangzhou, China
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21
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Gao CH, Wei WP, Tao HL, Cai LK, Jia WZ, Hu L, Yang M. Cross-talk between the three furA orthologs in Mycobacterium smegmatis and the contribution to isoniazid resistance. J Biochem 2019; 166:237-243. [PMID: 30993320 DOI: 10.1093/jb/mvz030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/10/2019] [Indexed: 01/18/2023] Open
Abstract
The ferric uptake regulator A (FurA) plays an essential role in responding to oxidative stress in mycobacteria. The genome of Mycobacterium smegmatis harbours three FurA orthologs; however, the potential cross-talk and contribution to drug resistance of different furA operon remain underdetermined. In this study, we characterized the cross-regulation and effect in drug resistance of these orthologs from M. smegmatis. Cross-binding of FurA protein to furA promoter was observed. The binding of FurA1 to furA3p and FurA2 to furA1p or furA3p is even more pronounced than their self-binding. The three FurA proteins are all functional at repressing the expression of the peroxidase enzyme katG1/katG2 in vivo. When overexpressing any of the furA orthologs in M. smegmatis, the bacteria become more resistant to isoniazid (INH). This pattern is consistent with that in Mycobacterium bovis. However, the knockdown of furA does not affect the INH sensitivity. This is the first report of cross-talk and contribution to drug resistance of all three furA orthologs in M. smegmatis.
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Affiliation(s)
- Chun-Hui Gao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
| | - Wen-Ping Wei
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
| | - Hui-Ling Tao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
| | - Li-Kai Cai
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
| | - Wan-Zhong Jia
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, No. 1, Xujiaping, Chengguan District, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Lihua Hu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
| | - Min Yang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, China
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22
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Li W, Hu L, Xie Z, Xu H, Li M, Cui T, He ZG. Cyclic di-GMP integrates functionally divergent transcription factors into a regulation pathway for antioxidant defense. Nucleic Acids Res 2019; 46:7270-7283. [PMID: 29982829 PMCID: PMC6101608 DOI: 10.1093/nar/gky611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/27/2018] [Indexed: 11/14/2022] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a global signaling molecule that modulates diverse cellular processes through its downstream receptors. However, no study has fully clarified the mechanisms by which c-di-GMP organizes functionally divergent regulators to drive the gene expression for coping with environmental stress. Here, we reported that c-di-GMP can integrate two functionally opposite receptor transcription factors, namely, LtmA and HpoR, into a pathway to regulate the antioxidant processes in Mycobacterium smegmatis. In contrast to HpoR, LtmA is an activator that positively regulates the expression of redox gene clusters and the mycobacterial H2O2 resistance. LtmA can physically interact with HpoR. A high level of c-di-GMP stimulates the positive regulation of LtmA and boosts the physical interaction between the two regulators, further enhancing the DNA-binding ability of LtmA and reducing the inhibitory activity of HpoR. Therefore, upon exposure to oxidative stress, c-di-GMP can orchestrate functionally divergent transcription factors to trigger antioxidant defense in mycobacteria. This finding presents a noteworthy example of how a bacterium remodels its transcriptional network via c-di-GMP in response to environmental stress.
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Affiliation(s)
- Weihui Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiwei Xie
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui Xu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meng Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Tao Cui
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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23
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Cordycepin kills Mycobacterium tuberculosis through hijacking the bacterial adenosine kinase. PLoS One 2019; 14:e0218449. [PMID: 31199855 PMCID: PMC6568415 DOI: 10.1371/journal.pone.0218449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 06/03/2019] [Indexed: 11/20/2022] Open
Abstract
Cordycepin is an efficient component of Cordyceps spp, a traditional Chinese medicine widely used for healthcare in China, and has been recently acted as a strong anticancer agent for clinic. However, whether and how it may play a role in combating tuberculosis, caused by Mycobacterium tuberculosis, remains unknown. Here we report that cordycepin can kill Mycobacterium by hijacking the bacterial adenosine kinase (AdoK), a purine salvage enzyme responsible for the phosphorylation of adenosine (Ado) to adenosine monophosphate (AMP). We show that cordycepin is a poor AdoK substrate but it competitively inhibits the catalytic activity of AdoK for adenosine phosphorylation. Cordycepin does not affect the activity of the human adenosine kinase (hAdoK), whereas hAdoK phosphorylates cordycepin to produce a new monophosphate derivative. Co-use of cordycepin and deoxycoformycin, an inhibitor of adenosine deaminase (ADD), more efficiently kills M. bovis and M. tuberculosis. The add-deleted mycobacterium is more sensitive to cordycepin. This study characterized cordycepin as a new mycobactericidal compound and also uncovered a potential anti-mycobacterial mechanism.
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24
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Liu Y, Xie Z, Zhou X, Li W, Zhang H, He ZG. NapM enhances the survival of Mycobacterium tuberculosis under stress and in macrophages. Commun Biol 2019; 2:65. [PMID: 30793043 PMCID: PMC6377630 DOI: 10.1038/s42003-019-0314-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 01/18/2019] [Indexed: 11/09/2022] Open
Abstract
Hostile environmental cues cause Mycobacterium tuberculosis to enter a state of slow growth for survival. However, the underlying regulatory mechanism remains unclear. DnaA is essential for DNA replication initiation and represents an efficient target for growth regulation in bacteria. Here, we show that the nucleoid-associated protein NapM is a DnaA antagonist, protecting M. tuberculosis from stress-mediated killing. NapM can be induced by diverse stressful signals. It binds to DnaA to inhibit both its DNA replication origin-binding and ATP hydrolysis activity. As a DnaA antagonist, NapM inhibits the mycobacterial DNA synthesis in vitro and in vivo in M. tuberculosis. Furthermore, we show that NapM contributes to the survival of M. tuberculosis under stress and within macrophages during infection. Our findings provide a previously unidentified mechanism of mycobacterial survival under stress and also suggest NapM as a potential drug target for tuberculosis control.
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Affiliation(s)
- Yu Liu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhiwei Xie
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiling Zhou
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Weihui Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hua Zhang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Zheng-Guo He
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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25
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Shur KV, Bekker OB, Zaichikova MV, Maslov DA, Akimova NI, Zakharevich NV, Chekalina MS, Danilenko VN. Genetic Aspects of Drug Resistance and Virulence in Mycobacterium tuberculosis. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418120141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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26
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Zhu C, Liu Y, Hu L, Yang M, He ZG. Molecular mechanism of the synergistic activity of ethambutol and isoniazid against Mycobacterium tuberculosis. J Biol Chem 2018; 293:16741-16750. [PMID: 30185616 DOI: 10.1074/jbc.ra118.002693] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/26/2018] [Indexed: 11/06/2022] Open
Abstract
Isoniazid (INH) and ethambutol (EMB) are two major first-line drugs for managing tuberculosis (TB), caused by the microbe Mycobacterium tuberculosis Although co-use of these two drugs is common in clinical practice, the mechanism for the potential synergistic interplay between them remains unclear. Here, we present first evidence that INH and EMB act synergistically through a transcriptional repressor of the inhA gene, the target gene of INH encoding an enoyl-acyl carrier protein reductase of the fatty acid synthase type II system required for bacterial cell wall integrity. We report that EMB binds a hypothetical transcription factor encoded by the Rv0273c gene, designated here as EtbR. Using DNA footprinting, we found that EtbR specifically recognizes a motif sequence in the upstream region of the inhA gene. Using isothermal titration calorimetry and surface plasmon resonance assays, we observed that EMB binds EtbR in a 1:1 ratio and thereby stimulates its DNA-binding activity. When a nonlethal dose of EMB was delivered in combination with INH, EMB increased the INH susceptibility of cultured M. tuberculosis cells. In summary, EMB induces EtbR-mediated repression of inhA and thereby enhances the mycobactericidal effect of INH. Our findings uncover a molecular mechanism for the synergistic activity of two important anti-TB drugs.
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Affiliation(s)
- Chen Zhu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu Liu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Min Yang
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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27
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Efflux pump inhibition by 11H-pyrido[2,1-b]quinazolin-11-one analogues in mycobacteria. Bioorg Med Chem 2018; 26:4942-4951. [DOI: 10.1016/j.bmc.2018.08.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/09/2018] [Accepted: 08/27/2018] [Indexed: 11/21/2022]
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28
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Characterization of a novel regulatory pathway for mannitol metabolism and its coordination with biofilm formation in Mycobacterium smegmatis. J Genet Genomics 2018; 45:477-488. [DOI: 10.1016/j.jgg.2018.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/26/2018] [Indexed: 01/03/2023]
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29
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Wei W, Zhang Y, Gao R, Li J, Xu Y, Wang S, Ji Q, Feng Y. Crystal structure and acetylation of BioQ suggests a novel regulatory switch for biotin biosynthesis in Mycobacterium smegmatis. Mol Microbiol 2018; 109:642-662. [PMID: 29995988 DOI: 10.1111/mmi.14066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2018] [Indexed: 12/24/2022]
Abstract
Biotin (vitamin B7), a sulfur-containing fatty acid derivative, is a nutritional virulence factor in certain mycobacterial species. Tight regulation of biotin biosynthesis is important because production of biotin is an energetically expensive process requiring 15-20 equivalents of ATP. The Escherichia coli bifunctional BirA is a prototypical biotin regulatory system. In contrast, mycobacterial BirA is an unusual biotin protein ligase without DNA-binding domain. Recently, we established a novel two-protein paradigm of BioQ-BirA. However, structural and molecular mechanism for BioQ is poorly understood. Here, we report crystal structure of the M. smegmatis BioQ at 1.9 Å resolution. Structure-guided functional mapping defined a seven residues-requiring motif for DNA-binding activity. Western blot and MALDI-TOF MS allowed us to unexpectedly discover that the K47 acetylation activates crosstalking of BioQ to its cognate DNA. More intriguingly, excess of biotin augments the acetylation status of BioQ in M. smegmatis. It seems likely that BioQ acetylation proceeds via a non-enzymatic mechanism. Mutation of this acetylation site K47 in BioQ significantly impairs its regulatory role in vivo. This explains in part (if not all) why BioQ has no detectable requirement of the presumable bio-5'-AMP effecter, which is a well-known ligand for the paradigm E. coli BirA regulator system. Unlike the scenario seen with E. coli carrying a single biotinylated protein, AccB, genome-wide search and Streptavidin blot revealed that no less than seven proteins require the rare post-translational modification, biotinylation in M. smegmatis, validating its physiological demand for biotin at relatively high level. Taken together, our finding defines a novel biotin regulatory machinery by BioQ, posing a possibility that development of new antibiotics targets biotin, the limited nutritional virulence factor in certain pathogenic mycobacterial species.
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Affiliation(s)
- Wenhui Wei
- Department of Medical Microbiology & Parasitology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Yifei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Rongsui Gao
- Department of Medical Microbiology & Parasitology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Jun Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310014, China
| | - Yongchang Xu
- Department of Medical Microbiology & Parasitology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Shihua Wang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Youjun Feng
- Department of Medical Microbiology & Parasitology and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.,Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, School of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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30
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Li W, Li M, Hu L, Zhu J, Xie Z, Chen J, He ZG. HpoR, a novel c-di-GMP effective transcription factor, links the second messenger's regulatory function to the mycobacterial antioxidant defense. Nucleic Acids Res 2018; 46:3595-3611. [PMID: 29490073 PMCID: PMC5909442 DOI: 10.1093/nar/gky146] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 01/06/2023] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a global signaling molecule that widely modulates diverse cellular processes. However, whether or not the c-di-GMP signal participates in regulation of bacterial antioxidant defense is unclear, and the involved regulators remain to be explored. In this study, we characterized HpoR as a novel c-di-GMP effective transcription factor and found a link between the c-di-GMP signal and the antioxidant regulation in Mycobacterium smegmatis. H2O2 stress induces c-di-GMP accumulation in M. smegmatis. High level of c-di-GMP triggers expression of a redox gene cluster, designated as hpoR operon, which is required for the mycobacterial H2O2 resistance. HpoR acts as an inhibitor of the hpoR operon and recognizes a 12-bp motif sequence within the upstream regulatory region of the operon. c-di-GMP specifically binds with HpoR at a ratio of 1:1. Low concentrations of c-di-GMP stimulate the DNA-binding activity of HpoR, whereas high concentrations of the signal molecule inhibit the activity. Strikingly, high level of c-di-GMP de-represses the intracellular association of HpoR with the regulatory region of the hpoR operon in M. smegmatis and enhances the mycobacterial H2O2 resistance. Therefore, we report a novel c-di-GMP effective regulator in mycobacteria, which extends the second messenger's function to bacterial antioxidant defense.
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Affiliation(s)
- Weihui Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meng Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingpeng Zhu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiwei Xie
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jiarui Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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31
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Li X, Mei H, Chen F, Tang Q, Yu Z, Cao X, Andongma BT, Chou SH, He J. Transcriptome Landscape of Mycobacterium smegmatis. Front Microbiol 2017; 8:2505. [PMID: 29326668 PMCID: PMC5741613 DOI: 10.3389/fmicb.2017.02505] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 12/01/2017] [Indexed: 11/13/2022] Open
Abstract
The non-pathogenic bacterium Mycobacterium smegmatis mc2155 has been widely used as a model organism in mycobacterial research, yet a detailed study about its transcription landscape remains to be established. Here we report the transcriptome, expression profiles and transcriptional structures through growth-phase-dependent RNA sequencing (RNA-seq) as well as other related experiments. We found: (1) 2,139 transcriptional start sites (TSSs) in the genome-wide scale, of which eight samples were randomly selected and further verified by 5′-RACE; (2) 2,233 independent monocistronic or polycistronic mRNAs in the transcriptome within the operon/sub-operon structures which are classified into five groups; (3) 47.50% (1016/2139) genes were transcribed into leaderless mRNAs, with the TSSs of 41.3% (883/2139) mRNAs overlapping with the first base of the annotated start codon. Initial amino acids of MSMEG_4921 and MSMEG_6422 proteins were identified by Edman degradation, indicating the presence of distinctive widespread leaderless features in M. smegmatis mc2155. (4) 150 genes with potentially wrong structural annotation, of which 124 proposed genes have been corrected; (5) eight highly active promoters, with their activities further determined by β-galactosidase assays. These data integrated the transcriptional landscape to genome information of model organism mc2155 and lay a solid foundation for further works in Mycobacterium.
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Affiliation(s)
- Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Han Mei
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fang Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qing Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhaoqing Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaojian Cao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Binda T Andongma
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- Institute of Biochemistry and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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32
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33
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Ali MK, Li X, Tang Q, Liu X, Chen F, Xiao J, Ali M, Chou SH, He J. Regulation of Inducible Potassium Transporter KdpFABC by the KdpD/KdpE Two-Component System in Mycobacterium smegmatis. Front Microbiol 2017; 8:570. [PMID: 28484428 PMCID: PMC5401905 DOI: 10.3389/fmicb.2017.00570] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/20/2017] [Indexed: 12/28/2022] Open
Abstract
Kdp-ATPase is an inducible high affinity potassium uptake system that is widely distributed in bacteria, and is generally regulated by the KdpD/KdpE two-component system (TCS). In this study, conducted on Mycobacterium smegmatis, the kdpFABC (encoding Kdp-ATPase) expression was found to be affected by low concentration of K+, high concentrations of Na+, and/or [Formula: see text] of the medium. The KdpE was found to be a transcriptional regulator that bound to a specific 22-bp sequence in the promoter region of kdpFABC operon to positively regulate kdpFABC expression. The KdpE binding motif was highly conserved in the promoters of kdpFABC among the mycobacterial species. 5'-RACE data indicated a transcriptional start site (TSS) of the kdpFABC operon within the coding sequence of MSMEG_5391, which comprised a 120-bp long 5'-UTR and an open reading frame of the 87-bp kdpF gene. The kdpE deletion resulted in altered growth rate under normal and low K+ conditions. Furthermore, under K+ limiting conditions, a single transcript (kdpFABCDE) spanning kdpFABC and kdpDE operons was observed. This study provided the first insight into the regulation of kdpFABC operon by the KdpD/KdpE TCS in M. smegmatis.
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Affiliation(s)
- Maria K Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Qing Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Xiaoyu Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Fang Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Jinfeng Xiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China.,Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan
| | - Shan-Ho Chou
- Institute of Biochemistry and NCHU Agricultural Biotechnology Center, National Chung Hsing UniversityTaichung, Taiwan
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural UniversityWuhan, China
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Padiadpu J, Baloni P, Anand K, Munshi M, Thakur C, Mohan A, Singh A, Chandra N. Identifying and Tackling Emergent Vulnerability in Drug-Resistant Mycobacteria. ACS Infect Dis 2016; 2:592-607. [PMID: 27759382 DOI: 10.1021/acsinfecdis.6b00004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The global mechanisms and associated molecular alterations that occur in drug-resistant mycobacteria are poorly understood. To address this, we obtain genomics data and then construct a genome-scale response network in isoniazid-resistant Mycobacterium smegmatis and apply a network-mining algorithm. Through this, we decipher global alterations in an unbiased manner and identify emergent vulnerabilities in resistant bacilli, of which redox response was prominent. Using phenotypic profiling, we find that resistant bacilli exhibit collateral sensitivity to several compounds that block antioxidant responses. We find that nanogram/milliliter concentrations of ebselen, vancomycin, and phenylarsine oxide, in combination with isoniazid, are highly effective against Mycobacterium tuberculosis H37Rv and three clinical drug-resistant strains. Dynamic measurements of cytoplasmic redox potential revealed a surprisingly diminished capacity of clinical drug-resistant strains to counteract oxidative stress, providing a mechanistic basis for efficient and synergistic mycobactericidal activity of the drug combinations. Ebselen and vancomycin appear to be promising repurposable drugs.
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Affiliation(s)
- Jyothi Padiadpu
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Priyanka Baloni
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Kushi Anand
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - MohamedHusen Munshi
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Chandrani Thakur
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Abhilash Mohan
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Amit Singh
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Nagasuma Chandra
- Department of Biochemistry, ‡Supercomputer Education and Research Centre, #Molecular Biophysics Unit, ΔMicrobiology and
Cellular Biology, and ⊥Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
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Novel TetR family transcriptional factor regulates expression of multiple transport-related genes and affects rifampicin resistance in Mycobacterium smegmatis. Sci Rep 2016; 6:27489. [PMID: 27271013 PMCID: PMC4895335 DOI: 10.1038/srep27489] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 05/17/2016] [Indexed: 02/08/2023] Open
Abstract
Transport-related genes significantly affect bacterial antibiotic resistance. However, the effects of these genes and their regulation of bacterial drug resistance in several mycobacterial species, including the fast-growing Mycobacterium smegmatis, the pathogen M. tuberculosis and M. avium have not been clearly characterized. We identified Ms4022 (MSMEG_4022) as a novel TetR family regulator that activates the expression of seven transport-related genes and affects drug resistance in M. smegmatis. Overexpression of Ms4022 inhibited M. smegmatis growth and enhanced mycobacterial resistance to the anti-tuberculosis drug rifampicin (RIF). By contrast, the Ms4022-deleted mycobacterial strain has shown sensitive to RIF. Ms4022 recognized three 19 bp non-palindromic motifs containing a 9 bp conserved region at their 5' end and it directly regulated seven transport-related genes, which affects mycobacterial resistance to RIF. Overexpression of three of seven transport-related genes (Ms1448, Ms1613, and Ms5278) inhibited the growth of M. smegmatis. This study improves our understanding of the function of mycobacterial transport-related genes and their regulation of bacterial drug resistance.
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Liu Y, Wang H, Cui T, Zhou X, Jia Y, Zhang H, He ZG. NapM, a new nucleoid-associated protein, broadly regulates gene expression and affects mycobacterial resistance to anti-tuberculosis drugs. Mol Microbiol 2016; 101:167-81. [DOI: 10.1111/mmi.13383] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Yu Liu
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
| | - Hongyang Wang
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
| | - Tao Cui
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
| | - Xiling Zhou
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
| | - Yanxia Jia
- Division of Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
| | - Hua Zhang
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, Department of Biological Science, College of Life Science and Technology, Huazhong Agricultural University; Wuhan 430070 China
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Abstract
Discontinuity of both strands of the chromosome is a lethal event in all living organisms because it compromises chromosome replication. As such, a diversity of DNA repair systems has evolved to repair double-strand DNA breaks (DSBs). In part, this diversity of DSB repair systems has evolved to repair breaks that arise in diverse physiologic circumstances or sequence contexts, including cellular states of nonreplication or breaks that arise between repeats. Mycobacteria elaborate a set of three genetically distinct DNA repair pathways: homologous recombination, nonhomologous end joining, and single-strand annealing. As such, mycobacterial DSB repair diverges substantially from the standard model of prokaryotic DSB repair and represents an attractive new model system. In addition, the presence in mycobacteria of a DSB repair system that can repair DSBs in nonreplicating cells (nonhomologous end joining) or when DSBs arise between repeats (single-strand annealing) has clear potential relevance to Mycobacterium tuberculosis pathogenesis, although the exact role of these systems in M. tuberculosis pathogenesis is still being elucidated. In this article we will review the genetics of mycobacterial DSB repair systems, focusing on recent insights.
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Hu J, Zhao L, Yang M. A GntR family transcription factor positively regulates mycobacterial isoniazid resistance by controlling the expression of a putative permease. BMC Microbiol 2015; 15:214. [PMID: 26474554 PMCID: PMC4609117 DOI: 10.1186/s12866-015-0556-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 10/08/2015] [Indexed: 01/13/2023] Open
Abstract
Background Bacteria use transcriptional regulation to respond to environmental stresses. Specifically, exposure to antibacterial drugs is deemed to be an atypical stress, and altering transcriptional regulation in response to such stress can increase bacterial drug resistance. However, only a few transcription factors that regulate drug resistance have been reported. Results In the present study, a GntR family transcription factor, encoded by the MSMEG_0535 (Ms0535) gene, was shown to be an isoniazid (INH) resistance regulator in Mycobacterium smegmatis. When the Ms0535 gene was overexpressed, cells showed a significant increase in INH resistance. First, the interaction between Ms0535 and its own promoter was determined, and a conserved 26-bp palindromic DNA binding motif was identified using electrophoretic mobility shift and DNaseI footprinting assays. Second, quantitative reverse transcription-PCR assays showed that Ms0535 acted as a transcriptional activator, and positively regulated its own expression, as well as that of a permease encoded by the MSMEG_0534 (Ms0534) gene. Similar to the case for the Ms0535 gene, a recombinant Ms0534-overexpressing strain also exhibited increased INH resistance compared with the wild-type strain. Furthermore, we showed that Ms0535 and Ms0534 deletion strains were more sensitive to INH than the wild-type strain. Interestingly, overexpressing Ms0534 in the Ms0535 deletion strain enhanced its INH resistance. In contrast, the Ms0534 deletion strain was still sensitive to INH even when Ms0535 was overexpressed. These findings suggest that Ms0534 is an effector protein that affects INH resistance in M. smegmatis. Conclusions In summary, the GntR transcriptional regulator Ms0535 positively regulates INH resistance by transcriptionally regulating the expression of the Ms0534 permease in M. smegmatis. These results improve our understanding of the role of transcriptional regulation in INH drug resistance in mycobacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0556-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jialing Hu
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Lei Zhao
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Min Yang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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Yang M, Gao CH, Hu J, Zhao L, Huang Q, He ZG. InbR, a TetR family regulator, binds with isoniazid and influences multidrug resistance in Mycobacterium bovis BCG. Sci Rep 2015; 5:13969. [PMID: 26353937 PMCID: PMC4564863 DOI: 10.1038/srep13969] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/12/2015] [Indexed: 02/03/2023] Open
Abstract
Isoniazid (INH), an anti-tuberculosis (TB) drug, has been widely used for nearly 60 years. However, the pathway through which Mycobacterium tuberculosis responds INH remain largely unclear. In this study, we characterized a novel transcriptional factor, InbR, which is encoded by Rv0275c and belongs to the TetR family, that is directly responsive to INH. Disrupting inbR made mycobacteria more sensitive to INH, whereas overexpressing inbR decreased bacterial susceptibility to the drug. InbR could bind specifically to the upstream region of its own operon at two inverted repeats and act as an auto-repressor. Furthermore, InbR directly bind with INH, and the binding reduced InbR’s DNA-binding ability. Interestingly, susceptibilities were also changed by InbR for other anti-TB drugs, such as rifampin, implying that InbR may play a role in multi-drug resistance. Additionally, microarray analyses revealed a portion genes of the inbR regulon have similar expression patterns in inbR-overexpressing strain and INH-treated wild type strain, suggesting that these genes, for example iniBAC, may be responsible to the drug resistance of inbR-overexpressing strain. The regulation of these genes by InbR were further assessed by ChIP-seq assay. InbR may regulate multiple drug resistance of mycobacteria through the regulation of these genes.
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Affiliation(s)
- Min Yang
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chun-Hui Gao
- School of Life Sciences and CAS Key Laboratory of Innate Immunity and Chronic Disease, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Jialing Hu
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lei Zhao
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Tang Q, Luo Y, Zheng C, Yin K, Ali MK, Li X, He J. Functional Analysis of a c-di-AMP-specific Phosphodiesterase MsPDE from Mycobacterium smegmatis. Int J Biol Sci 2015; 11:813-24. [PMID: 26078723 PMCID: PMC4466462 DOI: 10.7150/ijbs.11797] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/04/2015] [Indexed: 12/21/2022] Open
Abstract
Cyclic di‑AMP (c-di-AMP) is a second signaling molecule involved in the regulation of bacterial physiological processes and interaction between pathogen and host. However, the regulatory network mediated by c-di-AMP in Mycobacterium remains obscure. In M. smegmatis, a diadenylate cyclase (DAC) was reported recently, but there is still no investigation on c-di-AMP phosphodiesterase (PDE). Here, we provide a systematic study on signaling mechanism of c-di-AMP PDE in M. smegmatis. Based on our enzymatic analysis, MsPDE (MSMEG_2630), which contained a DHH-DHHA1 domain, displayed a 200-fold higher hydrolytic efficiency (kcat/Km) to c-di-AMP than to c-di-GMP. MsPDE was capable of converting c-di-AMP to pApA and AMP, and hydrolyzing pApA to AMP. Site-directed mutations in DHH and DHHA1 revealed that DHH domain was critical for the phosphodiesterase activity. To explore the regulatory role of c-di-AMP in vivo, we constructed the mspde mutant (Δmspde) and found that deficiency of MsPDE significantly enhanced intracellular C12-C20 fatty acid accumulation. Deficiency of DAC in many bacteria results in cell death. However, we acquired the M. smegmatis strain with DAC gene disrupted (ΔmsdisA) by homologous recombination approach. Deletion of msdisA reduced bacterial C12-C20 fatty acids production but scarcely affected bacterial survival. We also provided evidences that superfluous c-di-AMP in M. smegmatis could lead to abnormal colonial morphology. Collectively, our results indicate that MsPDE is a functional c-di-AMP-specific phosphodiesterase both in vitro and in vivo. Our study also expands the regulatory network mediated by c-di-AMP in M. smegmatis.
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Affiliation(s)
- Qing Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Yunchao Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Cao Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Kang Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Maria Kanwal Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
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Pan T, Huang P, Xiong G, Maser E. Isolation and identification of a repressor TetR for 3,17β-HSD expressional regulation in Comamonas testosteroni. Chem Biol Interact 2015; 234:205-12. [PMID: 25559855 DOI: 10.1016/j.cbi.2014.12.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/14/2014] [Accepted: 12/18/2014] [Indexed: 11/16/2022]
Abstract
Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17β-Hydroxysteroid dehydrogenase (3,17β-HSD) from C. testosteroni is a key enzyme in steroid degradation. Understanding the mechanism of 3,17β-HSD gene (βhsd) induction may help us to elucidate its complete molecular regulation. Sequencing the C. testosteroni ATCC11996 genome lead us to identify the tetR (522 bp) downstream of βhsd. Two repeat sequences (RS; 13 bp), that are separated to each other by 1661 bp, were found upstream of βhsd. A bioinformatic analysis revealed that TetR family proteins act as transcriptional repressors which are sensitive to environmental signals. Since, C. testosteroni responds to environmental steroid induction and upregulates steroid catabolic genes, we hypothesized that TetR might act in C. testosteroni as repressor for βhsd expression. The tetR was cloned into different plasmids, including an EGFP reporter system, for functional characterization and/or overexpression. The data indicate that, indeed, TetR acts as a repressor for 3,17β-HSD expression. Testosterone in turn, which is known to induce βhsd expression, could not resolve TetR repression. To further substantiate TetR as repressor for βhsd expression, a tetR gene knock-out mutant of C. testosteroni was generated. TetR gene knock-out mutants showed the same basal low level of βhsd expression as the C. testosteroni wild type cells. Interestingly, testosterone induction leads to a strong increase in βhsd expression, especially in the tetR gene knock-out mutants. The result with the knock-out mutant, in principle, supports our hypothesis that TetR is a repressor for βhsd expression, but the exact role of testosterone in this context remains unknown. Finally, it turned out that TetR is obviously also involved in the regulation of the hsdA gene.
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Affiliation(s)
- Tianyuan Pan
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany; Department of Family Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310000 Hangzhou, China
| | - Pu Huang
- Department of Biochemistry and Genetics, School of Medicine, Zhejiang University, 310058 Hangzhou, China
| | - Guangming Xiong
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany.
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Tang Q, Li X, Zou T, Zhang H, Wang Y, Gao R, Li Z, He J, Feng Y. Mycobacterium smegmatis BioQ defines a new regulatory network for biotin metabolism. Mol Microbiol 2014; 94:1006-1023. [PMID: 25287944 DOI: 10.1111/mmi.12817] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2014] [Indexed: 02/06/2023]
Abstract
Biotin (vitamin H), the sulfur-containing enzyme cofactor, is an essential micronutrient for three domains of life. Given the fact that biotin is an energetically expensive molecule whose de novo biosynthesis demands 20 ATP equivalents each, it is reasonable that bacteria have evolved diversified mechanisms in various microorganisms to tightly control biotin metabolism. Unlike the Escherichia coli BirA, the prototypical bi-functional version of biotin protein ligase (BPL) in that it acts as a repressor for biotin biosynthesis pathway, the BirA protein of Mycobacterium smegmatis (M. smegmatis), a closely relative of the tuberculosis-causing pathogen, Mycobacterium tuberculosis, lacked the DNA-binding activity. It raised a possibility that an alternative new regulator might be present to compensate the loss of regulatory function. Here we report that this is the case. Genomic context analyses of M. smegmatis detected a newly identified BioQ homolog classified into the TetR family of transcription factor and its recognizable palindromes. The M. smegmatis BioQ protein was overexpressed and purified to homogeneity. Size-exclusion chromatography combined with chemical cross-linking studies demonstrated that the BioQ protein had a propensity to dimerize. The promoters of bioFD and bioQ/B were mapped using 5'-RACE. Electrophoretic mobility shift assays revealed that BioQ binds specifically to the promoter regions of bioFD and bioQ/B. Further DNase I foot-printing elucidated the BioQ-binding palindromes. Site-directed mutagenesis suggested the important residues critical for BioQ/DNA binding. The isogenic mutant of bioQ (ΔbioQ) was generated using the approach of homologous recombination. The in vivo data from the real-time qPCR combined with the lacZ transcriptional fusion experiments proved that removal of bioQ gave significant increment with expression of bio operons. Also, expression of bio operons were repressed by exogenous addition of biotin, and this repression seemed to depend on the presence of BioQ protein. Thereby, we believed that M. smegmatis BioQ is not only a negative auto-regulator but also a repressor for bioFD and bioB operons involved in the biotin biosynthesis pathway. Collectively, this finding defined the two-protein paradigm of BirA and BioQ, representing a new mechanism for bacterial biotin metabolism.
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Affiliation(s)
- Qing Tang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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A novel marRAB operon contributes to the rifampicin resistance in Mycobacterium smegmatis. PLoS One 2014; 9:e106016. [PMID: 25153492 PMCID: PMC4143341 DOI: 10.1371/journal.pone.0106016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 07/25/2014] [Indexed: 12/30/2022] Open
Abstract
The multiple-antibiotic resistance regulator (MarR) plays an important role in modulating bacterial antibiotic resistance. However, the regulatory model of the marRAB operon in mycobacteria remains to be characterized. Here we report that a MarR, encoded by Ms6508, and its marRAB operon specifically contribute to rifampicin (RIF) resistance in Mycobacterium smegmatis. We show that the MarR recognizes a conserved 21-bp palindromic motif and negatively regulates the expression of two ABC transporters in the operon, encoded by Ms6509–6510. Unlike other known drug efflux pumps, overexpression of these two ABC transporters unexpectedly increased RIF sensitivity and deletion of these two genes increased mycobacterial resistance to the antibiotic. No change can be detected for the sensitivity of recombinant mycobacterial strains to three other anti-TB drugs. Furthermore, HPLC experiments suggested that Ms6509–Ms6510 could pump RIF into the mycobacterial cells. These findings indicated that the mycobacterial MarR functions as a repressor and constitutively inhibits the expression of the marRAB operon, which specifically contributes to RIF resistance in M. smegmatis. Therefore, our data suggest a new regulatory mechanism of RIF resistance and also provide the new insight into the regulatory model of a marRAB operon in mycobacteria.
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Bhukya H, Bhujbalrao R, Bitra A, Anand R. Structural and functional basis of transcriptional regulation by TetR family protein CprB from S. coelicolor A3(2). Nucleic Acids Res 2014; 42:10122-33. [PMID: 25092919 PMCID: PMC4150764 DOI: 10.1093/nar/gku587] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Antibiotic production and resistance pathways in Streptomyces are dictated by the interplay of transcriptional regulatory proteins that trigger downstream responses via binding to small diffusible molecules. To decipher the mode of DNA binding and the associated allosteric mechanism in the sub-class of transcription factors that are induced by γ-butyrolactones, we present the crystal structure of CprB in complex with the consensus DNA element to a resolution of 3.25 Å. Binding of the DNA results in the restructuring of the dimeric interface of CprB, inducing a pendulum-like motion of the helix-turn-helix motif that inserts into the major groove. The crystal structure revealed that, CprB is bound to DNA as a dimer of dimers with the mode of binding being analogous to the broad spectrum multidrug transporter protein QacR from the antibiotic resistant strain Staphylococcus aureus. It was demonstrated that the CprB displays a cooperative mode of DNA binding, following a clamp and click model. Experiments performed on a subset of DNA sequences from Streptomyces coelicolor A3(2) suggest that CprB is most likely a pleiotropic regulator. Apart from serving as an autoregulator, it is potentially a part of a network of proteins that modulates the γ-butyrolactone synthesis and antibiotic regulation pathways in S. coelicolor A3(2).
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Affiliation(s)
- Hussain Bhukya
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India IITB-Monash Research Academy, Mumbai 400076, Maharashtra, India
| | - Ruchika Bhujbalrao
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Aruna Bitra
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
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Shah SQA, Sørum H. Genetic localization of a TetR-like transcriptional regulator gene in Pseudomonas fluorescens isolated from farmed fish. J Appl Genet 2014; 55:541-4. [PMID: 24871198 DOI: 10.1007/s13353-014-0221-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 04/14/2014] [Accepted: 05/01/2014] [Indexed: 11/25/2022]
Abstract
Pseudomonas fluorescens isolates from Tanzanian tilapia ponds were found to possess a gene encoding a TetR-like transcriptional regulator protein. Phylogenetic analysis revealed close similarity to five previously reported GeneBank sequences which cluster separately from the other 70 members of this family. It is assumed that this TetR-like protein belongs to a new family of TetR-like proteins that has no direct link to the class 1 integron.
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Affiliation(s)
- S Q A Shah
- School of Veterinary Science, Oslo, Norway,
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Abstract
The most common prokaryotic signal transduction mechanisms are the one-component systems in which a single polypeptide contains both a sensory domain and a DNA-binding domain. Among the >20 classes of one-component systems, the TetR family of regulators (TFRs) are widely associated with antibiotic resistance and the regulation of genes encoding small-molecule exporters. However, TFRs play a much broader role, controlling genes involved in metabolism, antibiotic production, quorum sensing, and many other aspects of prokaryotic physiology. There are several well-established model systems for understanding these important proteins, and structural studies have begun to unveil the mechanisms by which they bind DNA and recognize small-molecule ligands. The sequences for more than 200,000 TFRs are available in the public databases, and genomics studies are identifying their target genes. Three-dimensional structures have been solved for close to 200 TFRs. Comparison of these structures reveals a common overall architecture of nine conserved α helices. The most important open question concerning TFR biology is the nature and diversity of their ligands and how these relate to the biochemical processes under their control.
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Liu L, Huang C, He ZG. A TetR family transcriptional factor directly regulates the expression of a 3-methyladenine DNA glycosylase and physically interacts with the enzyme to stimulate its base excision activity in Mycobacterium bovis BCG. J Biol Chem 2014; 289:9065-75. [PMID: 24509852 DOI: 10.1074/jbc.m113.528919] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
3-Methyladenine DNA glycosylase recognizes and excises a wide range of damaged bases and thus plays a critical role in base excision repair. However, knowledge on the regulation of DNA glycosylase in prokaryotes and eukaryotes is limited. In this study, we successfully characterized a TetR family transcriptional factor from Mycobacterium bovis bacillus Calmette-Guerin (BCG), namely BCG0878c, which directly regulates the expression of 3-methyladenine DNA glycosylase (designated as MbAAG) and influences the base excision activity of this glycosylase at the post-translational level. Using electrophoretic mobility shift assay and DNase I footprinting experiments, we identified two conserved motifs within the upstream region of mbaag specifically recognized by BCG0878c. Significant down-regulation of mbaag was observed in BCG0878c-overexpressed M. bovis BCG strains. By contrast, about 12-fold up-regulation of mbaag expression was found in bcg0878c-deleted mutant M. bovis BCG strains. β-Galactosidase activity assays also confirmed these results. Thus, BCG0878c can function as a negative regulator of mbaag expression. In addition, the regulator was shown to physically interact with MbAAG to enhance the ability of the glycosylase to bind damaged DNA. Interaction between the two proteins was further found to facilitate AAG-catalyzed removal of hypoxanthine from DNA. These results indicate that a TetR family protein can dually regulate the function of 3-methyladenine DNA glycosylase in M. bovis BCG both at the transcriptional and post-translational levels. These findings enhance our understanding of the expression and regulation of AAG in mycobacteria.
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Affiliation(s)
- Lei Liu
- From the National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Yang S, Gao Z, Li T, Yang M, Zhang T, Dong Y, He ZG. Structural basis for interaction between Mycobacterium smegmatis Ms6564, a TetR family master regulator, and its target DNA. J Biol Chem 2013; 288:23687-95. [PMID: 23803605 DOI: 10.1074/jbc.m113.468694] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Master regulators, which broadly affect expression of diverse genes, play critical roles in bacterial growth and environmental adaptation. However, the underlying mechanism by which such regulators interact with their cognate DNA remains to be elucidated. In this study, we solved the crystal structure of a broad regulator Ms6564 in Mycobacterium smegmatis and its protein-operator complex at resolutions of 1.9 and 2.5 Å, respectively. Similar to other typical TetR family regulators, two dimeric Ms6564 molecules were found to bind to opposite sides of target DNA. However, the recognition helix of Ms6564 inserted only slightly into the DNA major groove. Unexpectedly, 11 disordered water molecules bridged the interface of TetR family regulator DNA. Although the DNA was deformed upon Ms6564 binding, it still retained the conformation of B-form DNA. Within the DNA-binding domain of Ms6564, only two amino acids residues directly interacted with the bases of cognate DNA. Lys-47 was found to be essential for the specific DNA binding ability of Ms6564. These data indicate that Ms6564 can bind DNA with strong affinity but makes flexible contacts with DNA. Our study suggests that Ms6564 might slide more easily along the genomic DNA and extensively regulate the expression of diverse genes in M. smegmatis.
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Affiliation(s)
- Shifan Yang
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Zhang L, Li W, He ZG. DarR, a TetR-like transcriptional factor, is a cyclic di-AMP-responsive repressor in Mycobacterium smegmatis. J Biol Chem 2012; 288:3085-96. [PMID: 23250743 DOI: 10.1074/jbc.m112.428110] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cyclic dinucleotides, including cyclic di-AMP (c-di-AMP), are known to be ubiquitous second messengers involved in bacterial signal transduction. However, no transcriptional regulator has been characterized as a c-di-AMP receptor/effector to date. In the present study, using a c-di-AMP/transcription factor binding screen, we identified Ms5346, a TetR family regulator in Mycobacterium smegmatis, as a c-di-AMP receptor in bacteria. Ms5346 could specifically bind c-di-AMP with K(d) of 2.3 ± 0.5 μM. Using EMSA and DNase I footprinting assays, c-di-AMP was found to stimulate the DNA binding activity of Ms5346 and to enhance its ability to protect its target DNA sequence. A conserved 14-bp palindromic motif was identified as the DNA-binding site for Ms5346. Further, Ms5346 was found to negatively regulate expression of three target genes including Ms5347 (encoding a major facilitator family transporter), Ms5348 (encoding a medium chain fatty acyl-CoA ligase), and Ms5696 (encoding a cold shock protein, CspA). Ms5346 is the first cyclic di-AMP receptor regulator to be identified in bacteria, and we have designated it as DarR. Our findings enhance our understanding of the function and regulatory mechanism of the second messenger c-di-AMP in bacteria.
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Affiliation(s)
- Lei Zhang
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Li W, He ZG. LtmA, a novel cyclic di-GMP-responsive activator, broadly regulates the expression of lipid transport and metabolism genes in Mycobacterium smegmatis. Nucleic Acids Res 2012; 40:11292-307. [PMID: 23047950 PMCID: PMC3526308 DOI: 10.1093/nar/gks923] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In a bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP)/transcription factor binding screen, we identified Mycobacterium smegmatis Ms6479 as the first c-di-GMP-responsive transcriptional factor in mycobacteria. Ms6479 could specifically bind with c-di-GMP and recognize the promoters of 37 lipid transport and metabolism genes. c-di-GMP could enhance the ability of Ms6479 to bind to its target DNA. Furthermore, our results establish Ms6479 as a global activator that positively regulates the expression of diverse target genes. Overexpression of Ms6479 in M. smegmatis significantly reduced the permeability of the cell wall to crystal violet and increased mycobacterial resistance to anti-tuberculosis antibiotics. Interestingly, Ms6479 lacks the previously reported c-di-GMP binding motifs. Our findings introduce Ms6479 (here designated LtmA for lipid transport and metabolism activator) as a new c-di-GMP-responsive regulator.
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Affiliation(s)
- Weihui Li
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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