Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid...Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth,whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF[1], relBE[2] and chpIK[3]. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation paths (as indicated by their 16s RNA sequences), co-evolution with their antitoxins was obvious.展开更多
Toxin-antitoxin(TA)systems are ubiquitous in bacteria and archaea.Most are composed of two neighboring genetic elements,a stable toxin capable of inhibiting crucial cellular processes,including replication,transcrip-t...Toxin-antitoxin(TA)systems are ubiquitous in bacteria and archaea.Most are composed of two neighboring genetic elements,a stable toxin capable of inhibiting crucial cellular processes,including replication,transcrip-tion,translation,cell division and membrane integrity,and an unstable antitoxin to counteract the toxicity of the toxin.Many new discoveries regarding the biochemical properties of the toxin and antitoxin components have been made since the first TA system was reported nearly four decades ago.The physiological functions of TA systems have been hotly debated in recent decades,and it is now increasingly clear that TA systems are important immune systems in prokaryotes.In addition to being involved in biofilm formation and persister cell formation,these modules are antiphage defense systems and provide host defenses against various phage infec-tions via abortive infection.In this review,we explore the potential applications of TA systems based on the recent progress made in elucidating TA functions.We first describe the most recent classification of TA systems and then introduce the biochemical functions of toxins and antitoxins,respectively.Finally,we primarily focus on and devote considerable space to the application of TA complexes in synthetic biology.展开更多
The type Ⅱ toxin-antitoxin genes are responsible for the phenotypic switch to a quasi-dormant state that enables cell survival under stresses,a similar function to heterocyst of cyanobacteria. In this paper,we partic...The type Ⅱ toxin-antitoxin genes are responsible for the phenotypic switch to a quasi-dormant state that enables cell survival under stresses,a similar function to heterocyst of cyanobacteria. In this paper,we particularly study the role of gene pair all3211-asl3212 under Spectinomycin stress to reveal how the type Ⅱ toxin-antitoxin involved in environmental stress responses. Bioinformatics prediction shows that toxin protein gene All3211 is homologous to Maz F,a member of maz EF family that encoding nucleases. We clone gene all3211-asl3212 into expression vectors to identify its molecular characteristics. Deletion mutant strains of all3211-asl3212 are selected in a tri-parental mating screen. Phenotype comparisons of mutant and wild type reveals no difference of single-deletion-mutants in pigment integrity,the sensitivity to antibiotics,and heterocyst formation. The results show that deletion mutation of single TAS gene pair all3211-asl3212 results in limited effects on the cellular growth of PCC 7120. Thus,we suggest that dosage compensating might be provided from redundant genes or bypass pathways to offset obvious phenotypic differences.展开更多
指出了大肠杆菌的毒素-抗毒素系统(TAs)能介导解离后致死机制维持细菌质粒的稳定性和参与环境胁迫诱导细菌生长抑制或死亡,在鱼腥藻PCC7120质粒上的基因对alr9029/asr9028具有与TA系统较高的同源性.为了证实该基因对属于TA系统,通过生...指出了大肠杆菌的毒素-抗毒素系统(TAs)能介导解离后致死机制维持细菌质粒的稳定性和参与环境胁迫诱导细菌生长抑制或死亡,在鱼腥藻PCC7120质粒上的基因对alr9029/asr9028具有与TA系统较高的同源性.为了证实该基因对属于TA系统,通过生物信息学分析了alr9029/asr9028的遗传结构,设计特异性引物,扩增得到大小为198 bp的asr9028和387 bp的alr9029.PCR产物经Bam H I和HindШ双酶切后被插入p MD18-T和p ET-30a中,依次构建克隆载体和表达载体.经SDS-PAGE电泳检测,含有His6标签的表达蛋白相对分子量分别为12.4k Da和19.2 k Da,且为可溶性蛋白.故初步认定asr9028为抗毒素基因,alr9029为毒素基因,二者共同构成一个TA系统.展开更多
基金This work was supported by the National High Technology Research and Development Program of China(Program No.2003AA223031).
文摘Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth,whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF[1], relBE[2] and chpIK[3]. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation paths (as indicated by their 16s RNA sequences), co-evolution with their antitoxins was obvious.
基金This work was supported by the National Science Foundation of China(31970037,42188102,91951203,31625001,32100030)Science&Technology Fundamental Resources Investigation Program(2022FY100600)+3 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02Y262)Guangdong Major Project of Basic and Applied Basic Research(2019B030302004)Guangdong Basic and Applied Basic Research Foundation(2022A1515010702)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0407).
文摘Toxin-antitoxin(TA)systems are ubiquitous in bacteria and archaea.Most are composed of two neighboring genetic elements,a stable toxin capable of inhibiting crucial cellular processes,including replication,transcrip-tion,translation,cell division and membrane integrity,and an unstable antitoxin to counteract the toxicity of the toxin.Many new discoveries regarding the biochemical properties of the toxin and antitoxin components have been made since the first TA system was reported nearly four decades ago.The physiological functions of TA systems have been hotly debated in recent decades,and it is now increasingly clear that TA systems are important immune systems in prokaryotes.In addition to being involved in biofilm formation and persister cell formation,these modules are antiphage defense systems and provide host defenses against various phage infec-tions via abortive infection.In this review,we explore the potential applications of TA systems based on the recent progress made in elucidating TA functions.We first describe the most recent classification of TA systems and then introduce the biochemical functions of toxins and antitoxins,respectively.Finally,we primarily focus on and devote considerable space to the application of TA complexes in synthetic biology.
基金Supported by the National Natural Science Foundation of China(31001099/C190101)Central University Natural Science Foundation of China(CJSl3003,CJS13004)Key Laboratory of Microbiology and Biotrans Formation Funded Projects of South-Central University for Nationalities(XJS09002)
文摘The type Ⅱ toxin-antitoxin genes are responsible for the phenotypic switch to a quasi-dormant state that enables cell survival under stresses,a similar function to heterocyst of cyanobacteria. In this paper,we particularly study the role of gene pair all3211-asl3212 under Spectinomycin stress to reveal how the type Ⅱ toxin-antitoxin involved in environmental stress responses. Bioinformatics prediction shows that toxin protein gene All3211 is homologous to Maz F,a member of maz EF family that encoding nucleases. We clone gene all3211-asl3212 into expression vectors to identify its molecular characteristics. Deletion mutant strains of all3211-asl3212 are selected in a tri-parental mating screen. Phenotype comparisons of mutant and wild type reveals no difference of single-deletion-mutants in pigment integrity,the sensitivity to antibiotics,and heterocyst formation. The results show that deletion mutation of single TAS gene pair all3211-asl3212 results in limited effects on the cellular growth of PCC 7120. Thus,we suggest that dosage compensating might be provided from redundant genes or bypass pathways to offset obvious phenotypic differences.
文摘指出了大肠杆菌的毒素-抗毒素系统(TAs)能介导解离后致死机制维持细菌质粒的稳定性和参与环境胁迫诱导细菌生长抑制或死亡,在鱼腥藻PCC7120质粒上的基因对alr9029/asr9028具有与TA系统较高的同源性.为了证实该基因对属于TA系统,通过生物信息学分析了alr9029/asr9028的遗传结构,设计特异性引物,扩增得到大小为198 bp的asr9028和387 bp的alr9029.PCR产物经Bam H I和HindШ双酶切后被插入p MD18-T和p ET-30a中,依次构建克隆载体和表达载体.经SDS-PAGE电泳检测,含有His6标签的表达蛋白相对分子量分别为12.4k Da和19.2 k Da,且为可溶性蛋白.故初步认定asr9028为抗毒素基因,alr9029为毒素基因,二者共同构成一个TA系统.
