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
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
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.
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.
