Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 140
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 625(7995): 585-592, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38200309

RESUMO

Oncogene-induced replication stress generates endogenous DNA damage that activates cGAS-STING-mediated signalling and tumour suppression1-3. However, the precise mechanism of cGAS activation by endogenous DNA damage remains enigmatic, particularly given that high-affinity histone acidic patch (AP) binding constitutively inhibits cGAS by sterically hindering its activation by double-stranded DNA (dsDNA)4-10. Here we report that the DNA double-strand break sensor MRE11 suppresses mammary tumorigenesis through a pivotal role in regulating cGAS activation. We demonstrate that binding of the MRE11-RAD50-NBN complex to nucleosome fragments is necessary to displace cGAS from acidic-patch-mediated sequestration, which enables its mobilization and activation by dsDNA. MRE11 is therefore essential for cGAS activation in response to oncogenic stress, cytosolic dsDNA and ionizing radiation. Furthermore, MRE11-dependent cGAS activation promotes ZBP1-RIPK3-MLKL-mediated necroptosis, which is essential to suppress oncogenic proliferation and breast tumorigenesis. Notably, downregulation of ZBP1 in human triple-negative breast cancer is associated with increased genome instability, immune suppression and poor patient prognosis. These findings establish MRE11 as a crucial mediator that links DNA damage and cGAS activation, resulting in tumour suppression through ZBP1-dependent necroptosis.


Assuntos
Transformação Celular Neoplásica , Proteína Homóloga a MRE11 , Nucleossomos , Nucleotidiltransferases , Humanos , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Dano ao DNA , Proteína Homóloga a MRE11/metabolismo , Necroptose , Nucleossomos/metabolismo , Nucleotidiltransferases/metabolismo , Radiação Ionizante , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Instabilidade Genômica
2.
Metab Eng ; 83: 52-60, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38521489

RESUMO

2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable pseudo-aromatic dicarboxylic acid, is a promising building block compound for manufacturing biodegradable polyesters. This study aimed to construct high-performance cell factories enabling the efficient production of PDC from glucose. Firstly, the effective enzymes of the PDC biosynthetic pathway were overexpressed on the chromosome of the 3-dehydroshikimate overproducing strain. Consequently, the one-step biosynthesis of PDC from glucose was achieved. Further, the PDC production was enhanced by multi-copy integration of the key gene PsligC encoding 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase and co-expression of Vitreoscilla hemoglobin. Subsequently, the PDC production was substantially improved by redistributing the metabolic flux for cell growth and PDC biosynthesis based on dynamically downregulating the expression of pyruvate kinase. The resultant strain PDC50 produced 129.37 g/L PDC from glucose within 78 h under fed-batch fermentation conditions, with a yield of 0.528 mol/mol and an average productivity of 1.65 g/L/h. The findings of this study lay the foundation for the potential industrial production of PDC.


Assuntos
Escherichia coli , Engenharia Metabólica , Poliésteres , Pironas , Escherichia coli/genética , Escherichia coli/metabolismo , Poliésteres/metabolismo , Pironas/metabolismo , Glucose/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Ácidos Dicarboxílicos/metabolismo
3.
Crit Rev Biotechnol ; : 1-19, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38232958

RESUMO

The market size of biosurfactants (BSs) has been expanding at an extremely fast pace due to their broad application scope. Therefore, the re-construction of cell factories with modified genomic and metabolic profiles for desired industrial performance has been an intriguing aspect. Typical mutagenesis approaches generate huge mutant libraries, whereas a battery of specific, robust, and cost-effective high-throughput screening (HTS) methods is requisite to screen target strains for desired phenotypes. So far, only a few specialized HTS assays have been developed for BSs that were successfully applied to obtain anticipated mutants. The most important milestones to reach, however, continue to be: specificity, sensitivity, throughput, and the potential for automation. Here, we discuss important colorimetric and fluorometric HTS approaches for possible intervention on automated HTS platforms. Moreover, we explain current bottlenecks in developing specialized HTS platforms for screening high-yielding producers and discuss possible perspectives for addressing such challenges.

4.
Electrophoresis ; 44(9-10): 854-863, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36645159

RESUMO

Recent research has questioned the validity of housekeeping proteins in Western blot. Our present study proposed new ideas for Western blot normalization that improved the reproducibility of scientific research. We used the Gene Expression Omnibus (GEO) database and the web tool GEO2R to exclude unstable housekeeping genes quickly. In ischemic heart tissues, actin and tubulin changed significantly, whereas no statistically significant changes were observed in the expression of genes relative to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Besides, the reliability of GAPDH was further examined by Western blot. Additionally, unstable housekeeping genes were found in other animal models of cardiovascular medicine. We also found that sodium dodecyl sulfate and temperature significantly impacted the results of Ponceau S staining. Membranes stained with Ponceau S after immunodetection could avoid this interference, and the coefficients of variation for post-immunodetection staining are lower than those produced by GAPDH immunodetection. Overall, we described a new use of differential gene expression analysis and proposed a modified Ponceau S staining method, which provided researchers with a proper loading control for Western blot and hence could improve reproducibility in research.


Assuntos
Actinas , Gliceraldeído-3-Fosfato Desidrogenases , Animais , Reprodutibilidade dos Testes , Actinas/análise , Gliceraldeído-3-Fosfato Desidrogenases/genética , Gliceraldeído-3-Fosfato Desidrogenases/análise , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Coloração e Rotulagem , Western Blotting
5.
Microb Cell Fact ; 22(1): 172, 2023 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-37667234

RESUMO

BACKGROUND: Pyruvate is a widely used value-added chemical which also serves as a hub of various metabolic pathways. The fastest-growing bacterium Vibrio natriegens is a promising chassis for synthetic biology applications with high substrate uptake rates. The aim of this study was to investigate if the high substrate uptake rates of V. natriegens enable pyruvate production at high productivities. RESULTS: Two prophage gene clusters and several essential genes for the biosynthesis of byproducts were first deleted. In order to promote pyruvate accumulation, the key gene aceE encoding pyruvate dehydrogenase complex E1 component was down-regulated to reduce the carbon flux into the tricarboxylic acid cycle. Afterwards, the expression of ppc gene encoding phosphoenolpyruvate carboxylase was fine-tuned to balance the cell growth and pyruvate synthesis. The resulting strain PYR32 was able to produce 54.22 g/L pyruvate from glucose within 16 h, with a yield of 1.17 mol/mol and an average productivity of 3.39 g/L/h. In addition, this strain was also able to efficiently convert sucrose or gluconate into pyruvate at high titers. CONCLUSION: A novel strain of V. natriegens was engineered which was capable to provide higher productivity in pyruvate synthesis. This study lays the foundation for the biosynthesis of pyruvate and its derivatives in fast-growing V. natriegens.


Assuntos
Ácido Pirúvico , Vibrio , Engenharia Metabólica , Vibrio/genética , Transporte Biológico
6.
Metab Eng ; 73: 225-234, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35987431

RESUMO

Methyl ketones (MK) are highly valuable fatty acid derivatives with broad applications. Microbes based biosynthesis represents an alternative route for production of these usually fossil based chemicals. In this study, we reported metabolic engineering of Saccharomyces cerevisiae to produce MK, including 2-nonanone, 2-undecanone, 2-tridecanone and 2-pentadecanone. Besides enhancing inherent peroxisomal fatty acids ß-oxidation cycle, a novel heterologous cytosolic fatty acids ß-oxidation pathway was constructed, and this resulted in an increased production of MK by 2-fold. To increase carbon fluxes to methyl ketones, the supply of precursors was enhanced by engineering lipid metabolism, including improving the intracellular biosynthesis of acyl-CoAs, weakening the consumption of acyl-CoAs for lipids storage, and reinforcing activation of free fatty acids to acyl-CoAs. Hereby the titer of MK was improved by 7-fold, reaching 143.72 mg/L. Finally, transcription factor engineering was employed to increase the biosynthesis of methyl ketones and it was found that overexpression of ADR1 can mimic the oleate activated biogenesis and proliferation of peroxisomes, which resulted in a further increased production of MK by 28%. With these modifications and optimization, up to 845 mg/L total MK were produced from glucose in fed-batch fermentation, which is the highest titer of methyl ketones reported produced by fungi.


Assuntos
Saccharomyces cerevisiae , Fatores de Transcrição , Acetona/metabolismo , Ácidos Graxos/metabolismo , Cetonas/metabolismo , Engenharia Metabólica/métodos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
7.
Crit Rev Biotechnol ; 42(4): 618-633, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34325575

RESUMO

Terpenoids are a large family of natural products with diversified structures and functions that are widely used in the food, pharmaceutical, cosmetic, and agricultural fields. However, the traditional methods of terpenoids production such as plant extraction and chemical synthesis are inefficient due to the complex processes, high energy consumption, and low yields. With progress in metabolic engineering and synthetic biology, microbial cell factories provide an interesting alternative for the sustainable production of terpenoids. The non-conventional yeast, Yarrowia lipolytica, is a promising host for terpenoid biosynthesis due to its inherent mevalonate pathway, high fluxes of acetyl-CoA and NADPH, and the naturally hydrophobic microenvironment. In this review, we highlight progress in the engineering of Y. lipolytica as terpenoid biomanufacturing factories, describing the different terpenoid biosynthetic pathways and summarizing various metabolic engineering strategies, including progress in genetic manipulation, dynamic regulation, organelle engineering, and terpene synthase variants.


Assuntos
Yarrowia , Acetilcoenzima A/metabolismo , Engenharia Metabólica/métodos , Biologia Sintética , Terpenos/metabolismo , Yarrowia/genética , Yarrowia/metabolismo
8.
Appl Microbiol Biotechnol ; 106(19-20): 6583-6593, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36109386

RESUMO

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) system is a powerful genome editing tool that has been successfully established in some filamentous fungi due to its high flexibility and efficiency. However, the potential toxicity of Cas9 restricts the further popularization and application of this system to some degree. The AMA1 element is a self-replicator derived from Aspergillus nidulans, and its derived vectors can be readily lost without selection. In this study, we eliminated Cas9 toxicity to Fusarium venenatum TB01 based on 100% AMA1-based Cas9 expression vector loss. Meanwhile, two available endogenous Pol III promoters (FvU6374 and Fv5SrRNA) used for sgRNA expression of the CRISPR/Cas9 system were excavated. Compared to FvU6374 (40-50%), Fv5SrRNA exhibited higher single-gene editing efficiency (> 85%), and the efficiency of simultaneous editing of the two genes using Fv5SrRNA was over 75%. Based on this system, a butanediol dehydrogenase encoding gene FvBDH was deleted, and the ethanol yield in variants increased by 52% compared with that of the wild-type. The highly efficient CRISPR/Cas9 system developed here lays the technical foundation for advancing the development of F. venenatum TB01 through metabolic engineering, and the obtained FvBDH gene-edited variants have the potential to simultaneously produce mycoprotein and ethanol by further gene modification and fermentation process optimization in the future.Key points• Cas9 toxicity disappeared and DNA-free gene-edited strains obtained after vector loss• Promoter Fv5SrRNA conferred TB01 higher gene editing efficiency than FvU6374•Deletion of the FvBDH gene resulted in a 52% increase in ethanol yield.


Assuntos
Proteínas Associadas a CRISPR , Edição de Genes , Proteínas Associadas a CRISPR/genética , Sistemas CRISPR-Cas , Etanol/toxicidade , Fusarium , Edição de Genes/métodos
9.
J Ind Microbiol Biotechnol ; 49(3)2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35259275

RESUMO

Droplet-based microfluidics has emerged as a powerful tool for single-cell screening with ultrahigh throughput, but its widespread application remains limited by the accessibility of a droplet microfluidic high-throughput screening (HTS) platform, especially to common laboratories having no background in microfluidics. Here, we first developed a microfluidic HTS platform based on fluorescence-activated droplet sorting technology. This platform allowed (i) encapsulation of single cells in monodisperse water-in-oil droplets; (ii) cell growth and protein production in droplets; and (iii) sorting of droplets based on their fluorescence intensities. To validate the platform, a model selection experiment of a binary mixture of Bacillus strains was performed, and a 45.6-fold enrichment was achieved at a sorting rate of 300 droplets per second. Furthermore, we used the platform for the selection of higher α-amylase-producing Bacillus licheniformis strains from a mutant library generated by atmospheric and room temperature plasma mutagenesis, and clones displaying over 50% improvement in α-amylase productivity were isolated. This droplet screening system could be applied to the engineering of other industrially valuable strains.


Assuntos
Bacillus , Microfluídica , Bacillus/genética , Biblioteca Gênica , Ensaios de Triagem em Larga Escala , alfa-Amilases/genética
10.
Crit Rev Biotechnol ; 41(7): 1023-1045, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33730939

RESUMO

Enzymes and cell factories play essential roles in industrial biotechnology for the production of chemicals and fuels. The properties of natural enzymes and cells often cannot meet the requirements of different industrial processes in terms of cost-effectiveness and high durability. To rapidly improve their properties and performances, laboratory evolution equipped with high-throughput screening methods and facilities is commonly used to tailor the desired properties of enzymes and cell factories, addressing the challenges of achieving high titer and the yield of the target products at high/low temperatures or extreme pH, in unnatural environments or in the presence of unconventional media. Droplet microfluidic screening (DMFS) systems have demonstrated great potential for exploring vast genetic diversity in a high-throughput manner (>106/h) for laboratory evolution and have been increasingly used in recent years, contributing to the identification of extraordinary mutants. This review highlights the recent advances in concepts and methods of DMFS for library screening, including the key factors in droplet generation and manipulation, signal sources for sensitive detection and sorting, and a comprehensive summary of success stories of DMFS implementation for engineering enzymes and cell factories during the past decade.


Assuntos
Ensaios de Triagem em Larga Escala , Microfluídica , Biotecnologia , Engenharia Celular
11.
Appl Microbiol Biotechnol ; 104(9): 4171-4184, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32189046

RESUMO

Microbial-produced branched-chain higher alcohols (BCHAs), such as isopropanol, isobutanol, and isopentanol in Escherichia coli, have emerged as promising alternative biofuels under development. Elucidating and improving the tolerance of E. coli to BCHAs are important issues for microbial production of BCHAs due to their physiological inhibitory effect. Previous works aimed at understanding the genetic basis of E. coli tolerance to BCHAs with a comparative genome, reverse engineering, or transcriptome approach have gained some important insights into the mechanism of tolerance. However, investigation on BCHA tolerance from the whole-genomic, transcriptomic, and metabolic levels via a systematic approach has not yet been completely elucidated. Here, in this study, genomic, transcriptomic, and 13C-metabolic flux analyses (13C-MFA) of an evolved E. coli strain adapted to BCHA tolerance were conducted. Genome mutation of negative regulation factor (rssB, acrB, and clpX) of RpoS level suggested upregulation of RpoS activity in BCHA tolerance of E. coli. From a more detailed perspective, enhanced energy metabolism was observed to be the main characteristic of E. coli strain tolerant to BCHAs. Enhanced energy metabolism has been achieved through several routes, which included redistribution of the central carbon metabolism, upregulation of the energy generation machinery, and facilitating the operation of electron transferring chain. Evidence of multiple solutions of genotype modification toward BCHA tolerance was also revealed through comparative analysis of previous works from different groups.


Assuntos
Adaptação Fisiológica , Butanóis/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Transcriptoma , Metabolismo Energético , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Genômica , Engenharia Metabólica , Análise do Fluxo Metabólico , Mutação
12.
Appl Microbiol Biotechnol ; 104(23): 9965-9977, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33064187

RESUMO

Nylon 5 and nylon 6,5 are recently explored as new commercial polyamides, of which the monomer includes δ-valerolactam. In this study, a novel catalytic activity of lysine 2-monooxygenase (DavB) was explored to produce δ-valerolactam from L-pipecolic acid (L-PA), functioning as oxidative decarboxylase on a cyclic compound. Recombinant Escherichia coli BS01 strain expressing DavB from Pseudomonas putida could synthesize δ-valerolactam from L-pipecolic acid with a concentration of 90.3 mg/L. Through the co-expression of recombinant apoptosis-inducing protein (rAIP) from Scomber japonicus, glucose dehydrogenase (GDH) from Bacillus subtilis, Δ1-piperideine-2-carboxylae reductase (DpkA) from P. putida and lysine permease (LysP) from E. coli with DavB, δ-valerolactam was produced with the highest concentration of 242 mg/L. α-Dioxygenases (αDox) from Oryza sativa could act as a similar catalyst on L-pipecolic acid. A novel δ-valerolactam synthesis pathway was constructed entirely via microbial conversion from feedstock lysine in this study. Our system has great potential in the development of a bio-nylon production process. KEY POINTS: • DavB performs as an oxidative decarboxylase on L-PA with substrate promiscuity. • Strain with rAIP, GDH, DpkA, LysP, and DavB coexpression could produce δ-valerolactam. • This is the first time to obtain valerolactam entirely via biosynthesis from lysine.


Assuntos
Escherichia coli , Engenharia Metabólica , Escherichia coli/genética , Lisina , Nylons , Piperidonas
13.
J Ind Microbiol Biotechnol ; 47(12): 1155-1160, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32980986

RESUMO

Genetically encoded biosensors are powerful tools used to screen metabolite-producing microbial strains. Traditionally, biosensor-based screening approaches also use fluorescence-activated cell sorting (FACS). However, these approaches are limited by the measurement of intracellular fluorescence signals in single cells, rather than the signals associated with populations comprising multiple cells. This characteristic reduces the accuracy of screening because of the variability in signal levels among individual cells. To overcome this limitation, we introduced an approach that combined biosensors with droplet microfluidics (i.e., fluorescence-activated droplet sorting, FADS) to detect labeled cells at a multi-copy level and in an independent droplet microenvironment. We used our previously reported genetically encoded biosensor, 3-dehydroshikimic acid (3-DHS), as a model with which to establish the biosensor-based FADS screening method. We then characterized and compared the effects of the sorting method on the biosensor-based screening system by subjecting the same mutant library to FACS and FADS. Notably, our developed biosensor-enabled, droplet microfluidics-based FADS screening system yielded an improved positive mutant enrichment rate and increased productivity by the best mutant, compared with the single-cell FACS system. In conclusion, the combination of a biosensor and droplet microfluidics yielded a more efficient screening method that could be applied to the biosensor-based high-throughput screening of other metabolites.


Assuntos
Técnicas Biossensoriais , Escherichia coli , Microfluídica , Ácido Chiquímico/análogos & derivados , Escherichia coli/metabolismo , Citometria de Fluxo/métodos , Biblioteca Gênica , Ensaios de Triagem em Larga Escala/métodos , Microfluídica/métodos
14.
Int J Mol Sci ; 21(12)2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32549393

RESUMO

Mid-life stage adults are at higher risk of developing venous thrombosis (VT)/thromboembolism (VT/E). Aging is characterized by an overproduction of reactive oxygen species (ROS), which could evoke a series of physiological changes involved in thrombosis. Here, we focus on the critical role of ROS within the red blood cell (RBC) in initiating venous thrombosis during aging. Growing evidence has shifted our interest in the role of unjustifiably unvalued RBCs in blood coagulation. RBCs can be a major source of oxidative stress during aging, since RBC redox homeostasis is generally compromised due to the discrepancy between prooxidants and antioxidants. As a result, ROS accumulate within the RBC due to the constant endogenous hemoglobin (Hb) autoxidation and NADPH oxidase activation, and the uptake of extracellular ROS released by other cells in the circulation. The elevated RBC ROS level affects the RBC membrane structure and function, causing loss of membrane integrity, and decreased deformability. These changes impair RBC function in hemostasis and thrombosis, favoring a hypercoagulable state through enhanced RBC aggregation, RBC binding to endothelial cells affecting nitric oxide availability, RBC-induced platelet activation consequently modulating their activity, RBC interaction with and activation of coagulation factors, increased RBC phosphatidylserine exposure and release of microvesicles, accelerated aging and hemolysis. Thus, RBC oxidative stress during aging typifies an ultimate mechanism in system failure, which can affect major processes involved in the development of venous thrombosis in a variety of ways. The reevaluated concept of the critical role of RBC ROS in the activation of thrombotic events during aging will help identify potential targets for novel strategies to prevent/reduce the risk for VT/E or VT/E recurrences in mid-life stage adults.


Assuntos
Envelhecimento/metabolismo , Eritrócitos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Trombose Venosa/metabolismo , Fatores de Coagulação Sanguínea/metabolismo , Hemostasia , Humanos , Estresse Oxidativo , Fosfatidilserinas/metabolismo
15.
Metab Eng ; 55: 23-32, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31220662

RESUMO

Bioplastics produced from microbial source are promising green alternatives to traditional petrochemical-derived plastics. Nonnatural straight-chain amino acids, especially 5-aminovalerate, 6-aminocaproate and 7-aminoheptanoate are potential monomers for the synthesis of polymeric bioplastics as their primary amine and carboxylic acid are ideal functional groups for polymerization. Previous pathways for 5-aminovalerate and 6-aminocaproate biosynthesis in microorganisms are derived from L-lysine catabolism and the citric acid cycle, respectively. Here, we show the construction of an artificial iterative carbon-chain-extension cycle in Escherichia coli for simultaneous production of a series of nonnatural amino acids with varying chain length. Overexpression of L-lysine α-oxidase in E. coli yields 2-keto-6-aminocaproate (2K6AC) as a non-native substrate for the artificial iterative carbon-chain-extension cycle. The chain-extended α-ketoacid products are decarboxylated and oxidized by an α-ketoacid decarboxylase and an aldehyde dehydrogenase, respectively, to yield their corresponding nonnatural straight-chain amino acids. The engineered system demonstrated simultaneous in vitro production of 99.16 mg/L of 5-aminovalerate, 46.96 mg/L of 6-aminocaproate and 4.78 mg/L of 7-aminoheptanoate after 8 h of enzyme catalysis starting from 2K6AC as the substrate. Furthermore, simultaneous production of 2.15 g/L of 5-aminovalerate, 24.12 mg/L of 6-aminocaproate and 4.74 mg/L of 7-aminoheptanoate was achieved in engineered E. coli. This work illustrates a promising metabolic-engineering strategy to access other medium-chain organic acids with -NH2, -SCH3, -SOCH3, -SH, -COOH, -COH, or -OH functional groups through carbon-chain-elongation chemistry.


Assuntos
Aminocaproatos/metabolismo , Ciclo do Ácido Cítrico , Proteínas de Escherichia coli , Escherichia coli , Engenharia Metabólica , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo
16.
FEMS Yeast Res ; 19(3)2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30776066

RESUMO

Enhanced capability of co-fermenting glucose and xylose at high temperature is highly desirable for yeast application in second-generation bioethanol production. Here, we obtained hybrid strains with improved glucose-xylose co-fermentation properties at high temperature by combining genome shuffling and adaptive evolution. Genome resequencing of these strains suggested predominantly inherited genetic information from one parental strain Spathaspora passalidarum SP rather than the other parental strain Saccharomyces cerevisiae ScY01, possibly due to that the CUG codon system of S. passalidarum might have systematically eliminated most of the functional proteins from S. cerevisiae through misfolding. Compared to SP, one-copy loss of a 146-kb fragment was found in the hybrid strain and regained after being evolved for a while, whereas one-copy loss of an 11-kb fragment was only found after being evolved for a longer time. Besides, the genes affected by nonsynonymous variants were also identified, especially the mutation S540F in the endoplasmic reticulum chaperon Kar2. Structural prediction indicated that S540F might change the substrate binding activity of Kar2, and thus play a role in preventing protein aggregation in yeast at high temperature. Our results illustrated genomic alterations during this process and revealed some genomic factors that might be involved to determine yeast thermotolerance.


Assuntos
Dissacarídeos/metabolismo , Fermentação , Temperatura Alta , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/genética , Etanol/metabolismo , Evolução Molecular , Proteínas Fúngicas/genética , Engenharia Genética , Genoma Fúngico , Genômica , Glucose/metabolismo , Proteínas de Choque Térmico HSP70/genética , Mutação , Termotolerância
17.
J Proteome Res ; 17(5): 1812-1825, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29611422

RESUMO

To gain a deep understanding of yeast-cell response to heat stress, multiple laboratory strains have been intensively studied via genome-wide expression analysis for the mechanistic dissection of classical heat-shock response (HSR). However, robust industrial strains of Saccharomyces cerevisiae have hardly been explored in global analysis for elucidation of the mechanism of thermotolerant response (TR) during fermentation. Herein, we employed data-independent acquisition and sequential window acquisition of all theoretical mass spectra based proteomic workflows to characterize proteome remodeling of an industrial strain, ScY01, responding to prolonged thermal stress or transient heat shock. By comparing the proteomic signatures of ScY01 in TR versus HSR as well as the HSR of the industrial strain versus a laboratory strain, our study revealed disparate response mechanisms of ScY01 during thermotolerant growth or under heat shock. In addition, through proteomics data-mining for decoding transcription factor interaction networks followed by validation experiments, we uncovered the functions of two novel transcription factors, Mig1 and Srb2, in enhancing the thermotolerance of the industrial strain. This study has demonstrated that accurate and high-throughput quantitative proteomics not only provides new insights into the molecular basis for complex microbial phenotypes but also pinpoints upstream regulators that can be targeted for improving the desired traits of industrial microorganisms.


Assuntos
Redes Reguladoras de Genes , Resposta ao Choque Térmico , Proteoma/análise , Saccharomyces cerevisiae/fisiologia , Termotolerância/genética , Fermentação , Complexo Mediador/fisiologia , Proteínas Repressoras/fisiologia , Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/análise , Proteínas de Saccharomyces cerevisiae/fisiologia , Especificidade da Espécie , Fatores de Tempo , Fatores de Transcrição
18.
J Biol Chem ; 292(50): 20707-20719, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29038295

RESUMO

An endoplasmic reticulum (ER) retention sequence (ERS) is a characteristic short sequence that mediates protein retention in the ER of eukaryotic cells. However, little is known about the detailed molecular mechanism involved in ERS-mediated protein ER retention. Using a new surface display-based fluorescence technique that effectively quantifies ERS-promoted protein ER retention within Saccharomyces cerevisiae cells, we performed comprehensive ERS analyses. We found that the length, type of amino acid residue, and additional residues at positions -5 and -6 of the C-terminal HDEL motif all determined the retention of ERS in the yeast ER. Moreover, the biochemical results guided by structure simulation revealed that aromatic residues (Phe-54, Trp-56, and other aromatic residues facing the ER lumen) in both the ERS (at positions -6 and -4) and its receptor, Erd2, jointly determined their interaction with each other. Our studies also revealed that this aromatic residue interaction might lead to the discriminative recognition of HDEL or KDEL as ERS in yeast or human cells, respectively. Our findings expand the understanding of ERS-mediated residence of proteins in the ER and may guide future research into protein folding, modification, and translocation affected by ER retention.


Assuntos
Aminoácidos Aromáticos/química , Retículo Endoplasmático/metabolismo , Modelos Moleculares , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Motivos de Aminoácidos , Substituição de Aminoácidos , Linhagem Celular , Retículo Endoplasmático/enzimologia , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Peso Molecular , Mutagênese Sítio-Dirigida , Mutação , Conformação Proteica , Engenharia de Proteínas , Domínios e Motivos de Interação entre Proteínas , Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Peptídeos/química , Receptores de Peptídeos/genética , Receptores de Peptídeos/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/enzimologia , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Especificidade da Espécie , Técnicas do Sistema de Duplo-Híbrido
19.
EMBO J ; 33(8): 862-77, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24534091

RESUMO

The MRE11-RAD50-NBS1 (MRN) complex is essential for the detection of DNA double-strand breaks (DSBs) and initiation of DNA damage signaling. Here, we show that Rad17, a replication checkpoint protein, is required for the early recruitment of the MRN complex to the DSB site that is independent of MDC1 and contributes to ATM activation. Mechanistically, Rad17 is phosphorylated by ATM at a novel Thr622 site resulting in a direct interaction of Rad17 with NBS1, facilitating recruitment of the MRN complex and ATM to the DSB, thereby enhancing ATM signaling. Repetition of these events creates a positive feedback for Rad17-dependent activation of MRN/ATM signaling which appears to be a requisite for the activation of MDC1-dependent MRN complex recruitment. A point mutation of the Thr622 residue of Rad17 leads to a significant reduction in MRN/ATM signaling and homologous recombination repair, suggesting that Thr622 phosphorylation is important for regulation of the MRN/ATM signaling by Rad17. These findings suggest that Rad17 plays a critical role in the cellular response to DNA damage via regulation of the MRN/ATM pathway.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Quebras de DNA de Cadeia Dupla , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Multimerização Proteica , Transdução de Sinais , Hidrolases Anidrido Ácido , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Linhagem Celular , Humanos , Proteína Homóloga a MRE11 , Fosforilação , Ligação Proteica , Processamento de Proteína Pós-Traducional
20.
FEMS Yeast Res ; 18(5)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29672693

RESUMO

TALENs-assisted multiplex editing (TAME) toolbox was previously established and used to successfully enhance ethanol stress tolerance of Saccharomyces cerevisiae laboratory strain. Here, the TAME toolbox was harnessed to improve and elucidate stress tolerances of S. cerevisiae industrial strain. One osmotolerant strain and one thermotolerant strain were selected from the mutant library generated by TAME at corresponding stress conditions, and exhibited 1.2-fold to 1.3-fold increases of fermentation capacities, respectively. Genome resequencing uncovered genomic alterations in the selected stress-tolerant strains, suggesting that cell wall and membrane-related proteins might be major factors behind improved tolerances of yeast to different stresses. Furthermore, amplified mitochondrial DNA might also have an important impact on increased stress tolerance. Unexpectedly, none of predesigned target potential TALENs modification sites showed any genomic variants in sequenced genomes of the selected strains, implicating that the improved stress tolerances might be due to indirect impacts of genome editing via TALENs rather than introducing genomic variants at potential target sites. Our findings not only confirmed TAME could be a useful tool to accelerate the breeding of industrial strain with multiple stress tolerance, but also supported the previous understandings of the complicated mechanisms of multiple stress tolerance in yeast.


Assuntos
Edição de Genes , Genoma Fúngico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição , Fermentação , Biblioteca Gênica , Genômica , Resposta ao Choque Térmico , Microbiologia Industrial , Mutação , Pressão Osmótica , Proteínas de Saccharomyces cerevisiae/metabolismo , Estresse Fisiológico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA