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Transcriptional Organization of the Salmonella Typhimurium Phage P22 pid ORFan Locus. Int J Mol Sci 2022; 23:ijms23031253. [PMID: 35163175 PMCID: PMC8835761 DOI: 10.3390/ijms23031253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/20/2022] Open
Abstract
Many phage genes lack sequence similarity to any other open reading frame (ORF) in current databases. These enigmatic ORFan genes can have a tremendous impact on phage propagation and host interactions but often remain experimentally unexplored. We previously revealed a novel interaction between phage P22 and its Salmonella Typhimurium host, instigated by the ORFan gene pid (for phage P22 encoded instigator of dgo expression) and resulting in derepression of the host dgoRKAT operon. The pid gene is highly expressed in phage carrier cells that harbor a polarly located P22 episome that segregates asymmetrically among daughter cells. Here, we discovered that the pid locus is fitted with a weak promoter, has an exceptionally long 5′ untranslated region that is instructive for a secondary pid mRNA species, and has a 3′ Rho-independent termination loop that is responsible for stability of the pid transcript.
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Jian H, Xu G, Yi Y, Hao Y, Wang Y, Xiong L, Wang S, Liu S, Meng C, Wang J, Zhang Y, Chen C, Feng X, Luo H, Zhang H, Zhang X, Wang L, Wang Z, Deng Z, Xiao X. The origin and impeded dissemination of the DNA phosphorothioation system in prokaryotes. Nat Commun 2021; 12:6382. [PMID: 34737280 PMCID: PMC8569181 DOI: 10.1038/s41467-021-26636-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Phosphorothioate (PT) modification by the dnd gene cluster is the first identified DNA backbone modification and constitute an epigenetic system with multiple functions, including antioxidant ability, restriction modification, and virus resistance. Despite these advantages for hosting dnd systems, they are surprisingly distributed sporadically among contemporary prokaryotic genomes. To address this ecological paradox, we systematically investigate the occurrence and phylogeny of dnd systems, and they are suggested to have originated in ancient Cyanobacteria after the Great Oxygenation Event. Interestingly, the occurrence of dnd systems and prophages is significantly negatively correlated. Further, we experimentally confirm that PT modification activates the filamentous phage SW1 by altering the binding affinity of repressor and the transcription level of its encoding gene. Competition assays, concurrent epigenomic and transcriptomic sequencing subsequently show that PT modification affects the expression of a variety of metabolic genes, which reduces the competitive fitness of the marine bacterium Shewanella piezotolerans WP3. Our findings strongly suggest that a series of negative effects on microorganisms caused by dnd systems limit horizontal gene transfer, thus leading to their sporadic distribution. Overall, our study reveals putative evolutionary scenario of the dnd system and provides novel insights into the physiological and ecological influences of PT modification.
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Affiliation(s)
- Huahua Jian
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Guanpeng Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yi Yi
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yali Hao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Xiong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Siyuan Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shunzhang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Canxing Meng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jiahua Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yue Zhang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Xiaoyuan Feng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Haiwei Luo
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hao Zhang
- Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Zhijun Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Development Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
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Akremi I, Holtappels D, Brabra W, Jlidi M, Hadj Ibrahim A, Ben Ali M, Fortuna K, Ahmed M, Meerbeek BV, Rhouma A, Lavigne R, Ben Ali M, Wagemans J. First Report of Filamentous Phages Isolated from Tunisian Orchards to Control Erwinia amylovora. Microorganisms 2020; 8:microorganisms8111762. [PMID: 33182526 PMCID: PMC7697814 DOI: 10.3390/microorganisms8111762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/28/2023] Open
Abstract
Newly discovered Erwinia amylovora phages PEar1, PEar2, PEar4 and PEar6 were isolated from three different orchards in North Tunisia to study their potential as biocontrol agents. Illumina sequencing revealed that the PEar viruses carry a single-strand DNA genome between 6608 and 6801 nucleotides and belong to the Inoviridae, making them the first described filamentous phages of E. amylovora. Interestingly, phage-infected cells show a decreased swimming and swarming motility and a cocktail of the four phages can significantly reduce infection of E. amylovora in a pear bioassay, potentially making them suitable candidates for phage biocontrol.
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Affiliation(s)
- Ismahen Akremi
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21-Box 2462, 3001 Leuven, Belgium; (D.H.); (K.F.); (R.L.)
| | - Dominique Holtappels
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21-Box 2462, 3001 Leuven, Belgium; (D.H.); (K.F.); (R.L.)
| | - Wided Brabra
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
- Astrum Biotech, Business Incubator, Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia
| | - Mouna Jlidi
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
| | - Adel Hadj Ibrahim
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
| | - Manel Ben Ali
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
- Astrum Biotech, Business Incubator, Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia
| | - Kiandro Fortuna
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21-Box 2462, 3001 Leuven, Belgium; (D.H.); (K.F.); (R.L.)
| | - Mohammed Ahmed
- Biomaterials Research Group (BIOMAT), Department of Oral Sciences, KU Leuven, Kapucijnenvoer 7-Block A Box 7001, 3000 Leuven, Belgium; (M.A.); (B.V.M.)
- Department of Dental Biomaterials, Tanta University, Biomedical Campus, 32511 Tanta, Gharbia Governorate, Egypt
| | - Bart Van Meerbeek
- Biomaterials Research Group (BIOMAT), Department of Oral Sciences, KU Leuven, Kapucijnenvoer 7-Block A Box 7001, 3000 Leuven, Belgium; (M.A.); (B.V.M.)
| | - Ali Rhouma
- Laboratory of Integrated Olive Production, Olive Tree Institute, BP208 Marhajene City, Tunis 1082, Tunisia;
| | - Rob Lavigne
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21-Box 2462, 3001 Leuven, Belgium; (D.H.); (K.F.); (R.L.)
| | - Mamdouh Ben Ali
- Laboratory of Microbial Biotechnology, Enzymatics and Biomolecules (LBMEB), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia; (I.A.); (W.B.); (M.J.); (A.H.I.); (M.B.A.); (M.B.A.)
- Astrum Biotech, Business Incubator, Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, P.O. Box 1177, Sfax 3018, Tunisia
| | - Jeroen Wagemans
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21-Box 2462, 3001 Leuven, Belgium; (D.H.); (K.F.); (R.L.)
- Correspondence: ; Tel.: +32-1637-4622
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Meng C, Li S, Fan Q, Chen R, Hu Y, Xiao X, Jian H. The thermo-regulated genetic switch of deep-sea filamentous phage SW1 and its distribution in the Pacific Ocean. FEMS Microbiol Lett 2020; 367:5854536. [PMID: 32510559 DOI: 10.1093/femsle/fnaa094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/05/2020] [Indexed: 02/01/2023] Open
Abstract
Viruses, especially bacteriophages, are thought to have important functions in the deep-sea ecosystem, but little is known about the induction mechanism of benthic phages in response to environmental change. Our prior work characterized a cold-active filamentous phage SW1 that infects the deep-sea bacterium Shewanella piezotolerans WP3; however, the underlying mechanism of the putative thermo-regulated genetic switch of SW1 is still unclear. In this study, the DNA copy number and mRNA abundance of the deep-sea phage SW1 were quantified in the whole life cycle of its host S. piezotolerans WP3 at different temperatures. Our results demonstrated that the induction of SW1 is dependent on a threshold temperature (4°C), but this dependency is not proportional to temperature gradient. RNA-Seq analyses revealed two highly transcribed regions at 4°C and verified the presence of a long 3' untranslated region (UTR) in the SW1 genome. Interestingly, recruitment analysis showed that SW1-like inoviruses prevail in deep sea (depth >1000 m) and photic epipelagic and mesopelagic zones (depth <1000 m), which suggested that the thermo-regulated genetic switch revealed in SW1 may be widely distributed in the ocean.
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Affiliation(s)
- Canxing Meng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Site Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Qilian Fan
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Rouke Chen
- School of Oceanography, State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Yang Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China.,School of Oceanography, State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China
| | - Huahua Jian
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
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Multiple Mechanisms Are Involved in Repression of Filamentous Phage SW1 Transcription by the DNA-Binding Protein FpsR. J Mol Biol 2019; 431:1113-1126. [DOI: 10.1016/j.jmb.2019.01.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/16/2019] [Accepted: 01/31/2019] [Indexed: 01/21/2023]
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6
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Tang XF, Zhou XL, Zhang Q, Chen P, Lu C, Pan MH. Bombyx mori cyclin-dependent kinase inhibitor is involved in regulation of the silkworm cell cycle. INSECT MOLECULAR BIOLOGY 2018; 27:404-413. [PMID: 29512228 DOI: 10.1111/imb.12381] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm.
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Affiliation(s)
- X-F Tang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - X-L Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Q Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - P Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture Genomics, Southwest University, Chongqing, China
| | - C Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture Genomics, Southwest University, Chongqing, China
| | - M-H Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture Genomics, Southwest University, Chongqing, China
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Nepal S, Kumar P. Dynamics of phenotypic switching of bacterial cells with temporal fluctuations in pressure. Phys Rev E 2018; 97:052411. [PMID: 29906911 DOI: 10.1103/physreve.97.052411] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Indexed: 06/08/2023]
Abstract
Phenotypic switching is one of the mechanisms by which bacteria thrive in ever changing environmental conditions around them. Earlier studies have shown that the application of steady high hydrostatic pressure leads to stochastic switching of mesophilic bacteria from a cellular phenotype having a normal cell cycle to another phenotype lacking cell division. Here, we have studied the dynamics of this phenotypic switching with fluctuating periodic pressure using a set of experiments and a theoretical model. Our results suggest that the phenotypic switching rate from high-pressure phenotype to low-pressure phenotype in the reversible regime is larger as compared to the switching rate from low-pressure phenotype to high-pressure phenotype. Furthermore, we find that even though the cell division and elongation are presumably regulated by a large number of genes the underlying physics of the dynamics of stochastic switching at high pressure is captured reasonably well by a simple two-state model.
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Affiliation(s)
- Sudip Nepal
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Pradeep Kumar
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
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Enhancing the Adaptability of the Deep-Sea Bacterium Shewanella piezotolerans WP3 to High Pressure and Low Temperature by Experimental Evolution under H 2O 2 Stress. Appl Environ Microbiol 2018; 84:AEM.02342-17. [PMID: 29269502 DOI: 10.1128/aem.02342-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/10/2017] [Indexed: 11/20/2022] Open
Abstract
Oxidative stresses commonly exist in natural environments, and microbes have developed a variety of defensive systems to counteract such events. Although increasing evidence has shown that high hydrostatic pressure (HHP) and low temperature (LT) induce antioxidant defense responses in cells, there is no direct evidence to prove the connection between antioxidant defense mechanisms and the adaptation of bacteria to HHP and LT. In this study, using the wild-type (WT) strain of a deep-sea bacterium, Shewanella piezotolerans WP3, as an ancestor, we obtained a mutant, OE100, with an enhanced antioxidant defense capacity by experimental evolution under H2O2 stress. Notably, OE100 exhibited better tolerance not only to H2O2 stress but also to HHP and LT (20 MPa and 4°C, respectively). Whole-genome sequencing identified a deletion mutation in the oxyR gene, which encodes the transcription factor that controls the oxidative stress response. Comparative transcriptome analysis showed that the genes associated with oxidative stress defense, anaerobic respiration, DNA repair, and the synthesis of flagella and bacteriophage were differentially expressed in OE100 compared with the WT at 20 MPa and 4°C. Genetic analysis of oxyR and ccpA2 indicated that the OxyR-regulated cytochrome c peroxidase CcpA2 significantly contributed to the adaptation of WP3 to HHP and LT. Taken together, these results confirmed the inherent relationship between antioxidant defense mechanisms and the adaptation of a benthic microorganism to HHP and LT.IMPORTANCE Oxidative stress exists in various niches, including the deep-sea ecosystem, which is an extreme environment with conditions of HHP and predominantly LT. Although previous studies have shown that HHP and LT induce antioxidant defense responses in cells, direct evidence to prove the connection between antioxidant defense mechanisms and the adaptation of bacteria to HHP and LT is lacking. In this work, using the deep-sea bacterium Shewanella piezotolerans WP3 as a model, we proved that enhancement of the adaptability of WP3 to HHP and LT can benefit from its antioxidant defense mechanism, which provided useful insight into the ecological roles of antioxidant genes in a benthic microorganism and contributed to an improved understanding of microbial adaptation strategies in deep-sea environments.
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Conjunction of G-quadruplex and stem-loop in the 5' untranslated region of mouse hepatocyte nuclear factor 4-alpha1 mediates strong inhibition of protein expression. Mol Cell Biochem 2018; 446:73-81. [PMID: 29332143 DOI: 10.1007/s11010-018-3274-3] [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: 09/20/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
Abstract
Hepatocyte nuclear factor 4-alpha (HNF4α) is a well-established master regulator of liver development and function. Restoration of HNF4α can treat multiple liver disorders and liver cancers. To date, HNF4α is still "undruggable" due to lack of known activating ligands. Thus, understanding the regulatory mechanism of HNF4α expression may help develop an alternative approach to modulate HNF4α protein levels. G-quadruplexes (G4) are non-canonical stable secondary structures discovered mostly in the promoters of oncogenes. Recent genome-wide studies demonstrate the enrichment of G4s in the 5' untranslated region (UTR). By protoporphyrin IX-binding assay and circular dichroism spectrum, we validated the presence of a chemically highly stable 4-ring G4 within the 5' UTR of mouse Hnf4a1. Our real-time PCR and Western blot data showed that the Hnf4a1 5' UTR caused a remarkable translational suppression regardless of a moderate effect on Hnf4a1 mRNA levels. The subsequent deletion/mutation analysis of Hnf4a1 5' UTR using dual-luciferase reporter assays further demonstrated that although the disruption of the chemically highly stable 4-ring G4 resulted in a marked attenuation of inhibition, the G4 alone only weakly inhibited translation. Likewise, disruption of a long stem-loop adjacent to the 4-ring G4 markedly attenuated translational inhibition, although the stem-loop alone only exerted a weak inhibitory effect. Thus, the tight conjunction of G4s and an adjacent stem-loop within the Hnf4a1 5' UTR was both necessary and sufficient to mediate the very strong translational repression. Our results establish a novel working model that a chemically stable G4 may require co-factors to be bio-stable for exerting biological functions.
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Xiong L, Jian H, Xiao X. Deep-Sea Bacterium Shewanella piezotolerans WP3 Has Two Dimethyl Sulfoxide Reductases in Distinct Subcellular Locations. Appl Environ Microbiol 2017; 83:e01262-17. [PMID: 28687647 PMCID: PMC5583501 DOI: 10.1128/aem.01262-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 06/30/2017] [Indexed: 11/20/2022] Open
Abstract
Dimethyl sulfoxide (DMSO) acts as a substantial sink for dimethyl sulfide (DMS) in deep waters and is therefore considered a potential electron acceptor supporting abyssal ecosystems. Shewanella piezotolerans WP3 was isolated from west Pacific deep-sea sediments, and two functional DMSO respiratory subsystems are essential for maximum growth of WP3 under in situ conditions (4°C/20 MPa). However, the relationship between these two subsystems and the electron transport pathway underlying DMSO reduction by WP3 remain unknown. In this study, both DMSO reductases (type I and type VI) in WP3 were found to be functionally independent despite their close evolutionary relationship. Moreover, immunogold labeling of DMSO reductase subunits revealed that the type I DMSO reductase was localized on the outer leaflet of the outer membrane, whereas the type VI DMSO reductase was located within the periplasmic space. CymA, a cytoplasmic membrane-bound tetraheme c-type cytochrome, served as a preferential electron transport protein for the type I and type VI DMSO reductases, in which type VI accepted electrons from CymA in a DmsE- and DmsF-independent manner. Based on these results, we proposed a core electron transport model of DMSO reduction in the deep-sea bacterium S. piezotolerans WP3. These results collectively suggest that the possession of two sets of DMSO reductases with distinct subcellular localizations may be an adaptive strategy for WP3 to achieve maximum DMSO utilization in deep-sea environments.IMPORTANCE As the dominant methylated sulfur compound in deep oceanic water, dimethyl sulfoxide (DMSO) has been suggested to play an important role in the marine biogeochemical cycle of the volatile anti-greenhouse gas dimethyl sulfide (DMS). Two sets of DMSO respiratory systems in the deep-sea bacterium Shewanella piezotolerans WP3 have previously been identified to mediate DMSO reduction under in situ conditions (4°C/20 MPa). Here, we report that the two DMSO reductases (type I and type VI) in WP3 have distinct subcellular localizations, in which type I DMSO reductase is localized to the exterior surface of the outer membrane and type VI DMSO reductase resides in the periplasmic space. A core electron transport model of DMSO reduction in WP3 was constructed based on genetic and physiological data. These results will contribute to a comprehensive understanding of the adaptation mechanisms of anaerobic respiratory systems in benthic microorganisms.
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Affiliation(s)
- Lei Xiong
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Huahua Jian
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
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