Cyanobacteria are promising oxygenic phototrophs for the production of various compounds.For their(photo)biotechnological exploitation,molecular tools are required,such as,for the introduction and expression of hetero...Cyanobacteria are promising oxygenic phototrophs for the production of various compounds.For their(photo)biotechnological exploitation,molecular tools are required,such as,for the introduction and expression of heterologous genes,or the modulation of enzyme activities or entire pathways.Concepts and strategies for the development of photosynthetic biomanufacturing technologies based on cyanobacteria have been extensively reviewed,as well as certain specialized aspects of their genetic manipulation.However,options for metabolic engineering of specific cyanobacterial cells are still less developed than those for other bacteria of biotechnological relevance.In addition to the standard genetic toolbox for“classical”metabolic engineering,we emphasize certain aspects,including recently developed vector systems for the extrachromosomal maintenance of genes and approaches based on clustered regularly interspaced short palindromic repeats(CRISPR)interference.We highlight the development of custom molecular tools for specific strains or products,discuss the emerging use of small regulatory proteins that appear promising for advanced metabolic engineering approaches to promote specific product formation,and provide an overview of suitable online resources.Furthermore,we discuss the current trends in this field and indicate their potential,such as using suitable product sensors that enable systematic screening,and optimization approaches.展开更多
Endoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression.A key endoribonuclease in Gram-negative bacteria is RNase E.To ensure an ap...Endoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression.A key endoribonuclease in Gram-negative bacteria is RNase E.To ensure an appropriate supply of RNase E,some bacteria,such as Escherichia coli,feedback-regulate RNase E expression via the rne 5′-untranslated region(5′UTR)in cis.However,the mechanisms involved in the control of RNase E in other bacteria largely remain unknown.Cyanobacteria rely on solar light as an energy source for photosynthesis,despite the inherent ultraviolet(UV)irradiation.In this study,we first investigated globally the changes in gene expression in the cyanobacterium Synechocystis sp.PCC ^(6)803 after a brief exposure to UV.Among the 407 responding genes 2 h after UV exposure was a prominent upregulation of rne mRNA level.Moreover,the enzymatic activity of RNase E rapidly increased as well,although the protein stability decreased.This unique response was underpinned by the increased accumulation of full-length rne mRNA caused by the stabilization of its 5′UTR and suppression of premature transcriptional termination,but not by an increased transcription rate.Mapping of RNA 3′ends and in vitro cleavage assays revealed that RNase E cleaves within a stretch of six consecutive uridine residues within the rne 5′UTR,indicating autoregulation.These observations suggest that RNase E in cyanobacteria contributes to reshaping the transcriptome during the UV stress response and that its required activity level is secured at the RNA level despite the enhanced turnover of the protein.展开更多
RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes.In bacteria,the mechanisms of RNA turnover have been extensively studied in the model...RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes.In bacteria,the mechanisms of RNA turnover have been extensively studied in the models Escherichia coli and Bacillus subtilis,but not much is known in other bacteria.Cyanobacteria are a diverse group of photosynthetic organisms that have great potential for the sustainable production of valuable products using CO_(2)and solar energy.A better understanding of the regulation of RNA decay is important for both basic and applied studies of cyanobacteria.Genomic analysis shows that cyanobacteria have more than 10 ribonucleases and related proteins in common with E.coli and B.subtilis,and only a limited number of them have been experimentally investigated.In this review,we summarize the current knowledge about these RNAturnover-related proteins in cyanobacteria.Although many of them are biochemically similar to their counterparts in E.coli and B.subtilis,they appear to have distinct cellular functions,suggesting a different mechanism of RNA turnover regulation in cyanobacteria.The identification of new players involved in the regulation of RNA turnover and the elucidation of their biological functions are among the future challenges in this field.展开更多
文摘Cyanobacteria are promising oxygenic phototrophs for the production of various compounds.For their(photo)biotechnological exploitation,molecular tools are required,such as,for the introduction and expression of heterologous genes,or the modulation of enzyme activities or entire pathways.Concepts and strategies for the development of photosynthetic biomanufacturing technologies based on cyanobacteria have been extensively reviewed,as well as certain specialized aspects of their genetic manipulation.However,options for metabolic engineering of specific cyanobacterial cells are still less developed than those for other bacteria of biotechnological relevance.In addition to the standard genetic toolbox for“classical”metabolic engineering,we emphasize certain aspects,including recently developed vector systems for the extrachromosomal maintenance of genes and approaches based on clustered regularly interspaced short palindromic repeats(CRISPR)interference.We highlight the development of custom molecular tools for specific strains or products,discuss the emerging use of small regulatory proteins that appear promising for advanced metabolic engineering approaches to promote specific product formation,and provide an overview of suitable online resources.Furthermore,we discuss the current trends in this field and indicate their potential,such as using suitable product sensors that enable systematic screening,and optimization approaches.
基金supported by Grants-in-Aid 25850056,S2306,and 20K05793 from the Ministry of Education,Culture,Sports,Science and Technology of Japan,the Advanced Low Carbon Technology Research and Development Program(ALCA)of the Japan Science and Technology Agency(JST)(to S.W.)the German Ministry of Education and Research(BMBF),grant no.031L0164B“RNAProNet”(to W.R.H.)+1 种基金the German Science Foundation(DFG)research training group MeInBio 322977937/GRK2344(to A.W.and W.R.H.)grant STE 1119/4-2(to C.S.).
文摘Endoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression.A key endoribonuclease in Gram-negative bacteria is RNase E.To ensure an appropriate supply of RNase E,some bacteria,such as Escherichia coli,feedback-regulate RNase E expression via the rne 5′-untranslated region(5′UTR)in cis.However,the mechanisms involved in the control of RNase E in other bacteria largely remain unknown.Cyanobacteria rely on solar light as an energy source for photosynthesis,despite the inherent ultraviolet(UV)irradiation.In this study,we first investigated globally the changes in gene expression in the cyanobacterium Synechocystis sp.PCC ^(6)803 after a brief exposure to UV.Among the 407 responding genes 2 h after UV exposure was a prominent upregulation of rne mRNA level.Moreover,the enzymatic activity of RNase E rapidly increased as well,although the protein stability decreased.This unique response was underpinned by the increased accumulation of full-length rne mRNA caused by the stabilization of its 5′UTR and suppression of premature transcriptional termination,but not by an increased transcription rate.Mapping of RNA 3′ends and in vitro cleavage assays revealed that RNase E cleaves within a stretch of six consecutive uridine residues within the rne 5′UTR,indicating autoregulation.These observations suggest that RNase E in cyanobacteria contributes to reshaping the transcriptome during the UV stress response and that its required activity level is secured at the RNA level despite the enhanced turnover of the protein.
基金supported by the National Natural Science Foundation of China(grant No.32070037)the Featured Institute Service Project from the Institute of Hydrobiology,the Chinese Academy of Sciences(grant No.Y85Z061601)the German Science Foundation(DFG)research training group BioInMe 322977937/GRK2344 and grant HE 2544/14-2(to Wolfgang R.Hess).
文摘RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes.In bacteria,the mechanisms of RNA turnover have been extensively studied in the models Escherichia coli and Bacillus subtilis,but not much is known in other bacteria.Cyanobacteria are a diverse group of photosynthetic organisms that have great potential for the sustainable production of valuable products using CO_(2)and solar energy.A better understanding of the regulation of RNA decay is important for both basic and applied studies of cyanobacteria.Genomic analysis shows that cyanobacteria have more than 10 ribonucleases and related proteins in common with E.coli and B.subtilis,and only a limited number of them have been experimentally investigated.In this review,we summarize the current knowledge about these RNAturnover-related proteins in cyanobacteria.Although many of them are biochemically similar to their counterparts in E.coli and B.subtilis,they appear to have distinct cellular functions,suggesting a different mechanism of RNA turnover regulation in cyanobacteria.The identification of new players involved in the regulation of RNA turnover and the elucidation of their biological functions are among the future challenges in this field.
