TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis...TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis,microbial competition,etc.T6SS-associated research is explosively expanding on numerous grounds that call for an efficient resource.The SecReT6 version3 provides comprehensive information on T6SS and the interactions between T6SS and T6SS-related proteins such as T6SS regulators and T6SS effectors.To assist T6SS researches like microbial competition and regulatory mechanisms,SecReT6 v3developed online tools for detection and analysis of T6SS and T6SS-related proteins and estimation of T6SS-dependent killing risk.We have identified a novel T6SS regulator and T6SS-dependent killing capacity in Acinetobacter baumannii clinical isolates with the aid of SecReT6 v3.17,212 T6SSs and plentiful T6SS-related proteins in 26,573 bacterial complete genomes were also detected,analyzed and incorporated into the database.The database is freely available at https://bioinfo-mml.sjtu.edu.cn/SecReT6/.展开更多
Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one ...Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.展开更多
In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis...In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis. Specific primers were designed according to the full-length geanme sequence of V. alginolyticus in GenBank. vscX gene （C, enBank accession number： FR780679） contained a 378 bp open reading frame （ORF）, encoding a putative protein of 125 amino acids. The theoretical molecular weight was 14.209 2 kD and theoretical pI was 5.75. By using Signal 4.1 Server and TMHMM Server 2.0, it was predicted that VscX protein had no transmembrane domain or signal peptide. The results of prediction using SoftBerry-Psite software showed that VscX protein contained three casein ki- nase lI phosphorylation sites, one N-myristoylation site and three C-terminal targeting signal sites. Subcellular localization revealed that VscX might be located in cytoplasm with the possibility of 56.5%. According to SMART prediction, VscX had one Pfam （ 1 - 125 aa） domain. Phylogenetic analysis revealed that VscX from V. alginolyticus and VscX from E parahemolyticus were clustered into the same group. Network interaction analysis showed that vscX was adjacent to vseY, vopB and sycN. By real-time fluorescent quantitative PCR technique and 2-△△△ method, the differences in expression levels of VscX mRNA in V. alginolyticus strain HY9901, T3SS deletion strain AvscO and complementary strain C-vscO at different growth stages were analyzed. The results showed that the expression levels of VscX mRNA in V. algianlyticus strain HY9901 and C-vscO were significantly up-regulated at stable growth stage （ P 〈0.01 ） ; the expression levels of VscX mRNA in deletion strain △vscO were significantly up-regulated at late growth stage （ P 〈0.01 ）. This study provided the basis for revealing the transport mechanism of T3SS injectisome of E alginolyticus.展开更多
Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cel...Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cell＇s functions. Specialized bacterial chaperones are required for effective secretion of some effectors. To identify the chaperone of ExoS, the representative effector secreted by the TTSS of P aeruginosa, we analyzed the role of a postulated chaperone termed Orfl. Methods By allelic exchange, we constructed the mutant with the deletion of gene Orfl. Analysis of secreted and cell-associated fractions was performed by SDS-PAGE and Western blotting. Using strain expressing in trans Orfl, tagged by V5 polypeptide and histidine, protein-protein interaction was determined by affinity resin pull-down assay in combination with MALDI-TOF The role of Orfl in the expression of exoS was evaluated by gene reporter analysis. Results Pull-down assay showed that Orfl binds to ExoS and ExoT. Secretion profile analysis showed that Orfl was necessary for the optimal secretion of ExoS and ExoT. However, Orfl had no effect on the expression of exoS. Conclusion Orfl is important for the secretion of ExoS probably by maintaining ExoS in a secretion-competent conformation. We propose to name Orfl as SpcS for ＂specific Pseudomonas chaperone for ExoS＂.展开更多
The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotub...The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotuber-culosis T6SS4 was recently reported to be involved in manganese acquisition;however,the underlying regulatory mechanism still remains unclear.In this study,we discovered that T6SS4 is regulated by ferric uptake regulator(Fur)in response to manganese ions(Mn^(2+)),and this negative regulation of Fur was proceeded by specifically recogniz-ing the promoter region of T6SS4 in Y.pseudotuberculosis.Furthermore,T6SS4 is induced by low Mn^(2+)and oxidative stress conditions via Fur,acting as a Mn^(2+)-responsive transcriptional regulator to maintain intracellular manganese homeostasis,which plays important role in the transport of Mn^(2+)for survival under oxidative stress.Our results pro-vide evidence that T6SS4 can enhance the oxidative stress resistance and virulence for Y.pseudotuberculosis.This study provides new insights into the regulation of T6SS4 via the Mn^(2+)-dependent transcriptional regulator Fur,and expands our knowledge of the regulatory mechanisms and functions of T6SS from Y.pseudotuberculosis.展开更多
VI型分泌系统(type VI secretion system,T6SS)具有转运效应蛋白分子到多种类型靶细胞的能力,广泛存在于革兰氏阴性菌,其结构复杂。当前T6SS结构模型表明其装置至少包含两个复合物:细胞膜跨膜相关装置和动态的噬菌体样结构。本文主要围...VI型分泌系统(type VI secretion system,T6SS)具有转运效应蛋白分子到多种类型靶细胞的能力,广泛存在于革兰氏阴性菌,其结构复杂。当前T6SS结构模型表明其装置至少包含两个复合物:细胞膜跨膜相关装置和动态的噬菌体样结构。本文主要围绕T6SS分泌装置的结构、结构元件相互作用功能以及影响装置表达和活性的条件和信号来进行简要综述。展开更多
基金supported by the Science and Technology Commission of Shanghai Municipality(19430750600,19JC1413000)the National Natural Science Foundation of China(31670074)+1 种基金the Medical Excellence Award Funded by the Creative Research Development Grant from the First Affiliated Hospital of Guangxi Medical University(XK2019025)the Science Fund of the Republic of Serbia(7750294,q-bio BDS)。
文摘TypeⅥSecretion System(T6SS)plays significant roles in microbial activities via injecting effectors into adjacent cells or environments.T6SS increasingly gained attention due to its important influence on pathogenesis,microbial competition,etc.T6SS-associated research is explosively expanding on numerous grounds that call for an efficient resource.The SecReT6 version3 provides comprehensive information on T6SS and the interactions between T6SS and T6SS-related proteins such as T6SS regulators and T6SS effectors.To assist T6SS researches like microbial competition and regulatory mechanisms,SecReT6 v3developed online tools for detection and analysis of T6SS and T6SS-related proteins and estimation of T6SS-dependent killing risk.We have identified a novel T6SS regulator and T6SS-dependent killing capacity in Acinetobacter baumannii clinical isolates with the aid of SecReT6 v3.17,212 T6SSs and plentiful T6SS-related proteins in 26,573 bacterial complete genomes were also detected,analyzed and incorporated into the database.The database is freely available at https://bioinfo-mml.sjtu.edu.cn/SecReT6/.
基金supported by the National Natural Science Foundation of China (No. 81201322)the Priority Project on Infectious Disease Control and Prevention 2011ZX10004-001 and 2013ZX10003006-002 by the Chinese Ministry of Science and Technology and the Chinese Ministry of Healththe Foundation of State Key Laboratory for Infectious Disease Prevention and Control (Grand No. 2011SKLID303)
文摘Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.
基金Supported by National Natural Science Foundation of China(31402344,31572656)Major Program of Natural Science Foundation of Guangdong Province(2015A030308020)
文摘In order to enrich the research about type III secretion system （T3SS） injectisome of Vibrio alginolyticus, vscX gene was cloned from E algianlyticus strain HY9901 for bioinformatics analysis and expression analysis. Specific primers were designed according to the full-length geanme sequence of V. alginolyticus in GenBank. vscX gene （C, enBank accession number： FR780679） contained a 378 bp open reading frame （ORF）, encoding a putative protein of 125 amino acids. The theoretical molecular weight was 14.209 2 kD and theoretical pI was 5.75. By using Signal 4.1 Server and TMHMM Server 2.0, it was predicted that VscX protein had no transmembrane domain or signal peptide. The results of prediction using SoftBerry-Psite software showed that VscX protein contained three casein ki- nase lI phosphorylation sites, one N-myristoylation site and three C-terminal targeting signal sites. Subcellular localization revealed that VscX might be located in cytoplasm with the possibility of 56.5%. According to SMART prediction, VscX had one Pfam （ 1 - 125 aa） domain. Phylogenetic analysis revealed that VscX from V. alginolyticus and VscX from E parahemolyticus were clustered into the same group. Network interaction analysis showed that vscX was adjacent to vseY, vopB and sycN. By real-time fluorescent quantitative PCR technique and 2-△△△ method, the differences in expression levels of VscX mRNA in V. alginolyticus strain HY9901, T3SS deletion strain AvscO and complementary strain C-vscO at different growth stages were analyzed. The results showed that the expression levels of VscX mRNA in V. algianlyticus strain HY9901 and C-vscO were significantly up-regulated at stable growth stage （ P 〈0.01 ） ; the expression levels of VscX mRNA in deletion strain △vscO were significantly up-regulated at late growth stage （ P 〈0.01 ）. This study provided the basis for revealing the transport mechanism of T3SS injectisome of E alginolyticus.
基金This research was supported by the association "Vaincre la Mucoviscidose" of France
文摘Objective Pseudomonas aeruginosa is a ubiquitous and opportunistic pathogen that uses the type Ⅲ secretion system （TTSS） to inject effector proteins directly into the cytosol of target cells to subvert the host cell＇s functions. Specialized bacterial chaperones are required for effective secretion of some effectors. To identify the chaperone of ExoS, the representative effector secreted by the TTSS of P aeruginosa, we analyzed the role of a postulated chaperone termed Orfl. Methods By allelic exchange, we constructed the mutant with the deletion of gene Orfl. Analysis of secreted and cell-associated fractions was performed by SDS-PAGE and Western blotting. Using strain expressing in trans Orfl, tagged by V5 polypeptide and histidine, protein-protein interaction was determined by affinity resin pull-down assay in combination with MALDI-TOF The role of Orfl in the expression of exoS was evaluated by gene reporter analysis. Results Pull-down assay showed that Orfl binds to ExoS and ExoT. Secretion profile analysis showed that Orfl was necessary for the optimal secretion of ExoS and ExoT. However, Orfl had no effect on the expression of exoS. Conclusion Orfl is important for the secretion of ExoS probably by maintaining ExoS in a secretion-competent conformation. We propose to name Orfl as SpcS for ＂specific Pseudomonas chaperone for ExoS＂.
基金supported by grants of the National Key R&D Program of China(Grants 2018YFA0901200)National Natural Science Foundation of China(Grants 31725003,31970114,32100034,and 32100149)+2 种基金Scientific Startup Foundation for Doctors of Northwest A and F University(Z1090122001 and Z1090122002)the China Postdoctoral Science Foundation(Grant 2020 M673501)Young Talent Support Program of Shaanxi Province University(20220206).
文摘The type Ⅵ secretion system(T6SS)is a widespread protein secretion apparatus deployed by many Gram-negative bacterial species to interact with competitor bacteria,host organisms,and the environment.Yersinia pseudotuber-culosis T6SS4 was recently reported to be involved in manganese acquisition;however,the underlying regulatory mechanism still remains unclear.In this study,we discovered that T6SS4 is regulated by ferric uptake regulator(Fur)in response to manganese ions(Mn^(2+)),and this negative regulation of Fur was proceeded by specifically recogniz-ing the promoter region of T6SS4 in Y.pseudotuberculosis.Furthermore,T6SS4 is induced by low Mn^(2+)and oxidative stress conditions via Fur,acting as a Mn^(2+)-responsive transcriptional regulator to maintain intracellular manganese homeostasis,which plays important role in the transport of Mn^(2+)for survival under oxidative stress.Our results pro-vide evidence that T6SS4 can enhance the oxidative stress resistance and virulence for Y.pseudotuberculosis.This study provides new insights into the regulation of T6SS4 via the Mn^(2+)-dependent transcriptional regulator Fur,and expands our knowledge of the regulatory mechanisms and functions of T6SS from Y.pseudotuberculosis.
文摘VI型分泌系统(type VI secretion system,T6SS)具有转运效应蛋白分子到多种类型靶细胞的能力,广泛存在于革兰氏阴性菌,其结构复杂。当前T6SS结构模型表明其装置至少包含两个复合物:细胞膜跨膜相关装置和动态的噬菌体样结构。本文主要围绕T6SS分泌装置的结构、结构元件相互作用功能以及影响装置表达和活性的条件和信号来进行简要综述。
