scholarly journals Inhibition of protein expression by the interaction of G-Quadruplex and RHAU peptide in E. coli

2020 ◽  
Vol 22 (4) ◽  
pp. 378-384
Author(s):  
Tuom T.T Truong ◽  
Thu M.T. Dao ◽  
Trang P.T Phan ◽  
Hoang D Nguyen ◽  
Dung H Nguyen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Reporter Gene ◽  
Biomedical Applications ◽  
Fluorescent Protein ◽  
Rna Helicase ◽  
Biological Processes ◽  
E Coli ◽  
G Quadruplex ◽  
Peptide Interaction

Introduction: G-quadurplex (G4) formation plays a role in many biological processes such as replication, transcription, translation and telomeric maintenance. Stabilization of G4 structure by peptide has recently emerged as a potential approach in the regulation of protein expression. In this study, we reported on regulation of cyan fluorescent protein (CFP) expression by the interaction of G4 and RNA helicase associated with AU-rich elements (RHAU) peptide in E. coli. Methods: A sequence of TTGGGTGGGTGGGTGGGT (formed into G4 structure) was genetically applied to cfp gene as a reporter gene (g4-cfp). Both g4-cfp and DHX36 (or ΔDHX36) genes were cloned to pET-Duet1 vector that allowed to simultaneously express both G4-CFP protein and RHAU (or ΔRHAU) protein under IPTG inducer. Results: The level of G4-CFP expression in the presence of RHAU (pD64) was around 2-fold and 3-fold lower than that of G4-CFP expression in the presence of ΔRHAU (pD65) and G4-CFP expression alone (pD21), respectively. Conclusion: RHAU might selectively bind G4 structure of mRNA of G4-CFP, resulting in inhibition of G4-CFP expression in E. coli. The G4 and RHAU peptide interaction would provide a promising approach for inhibition of gene expression in many biomedical applications.  

Comparison of Vibrio and Firefly Luciferases as Reporter Gene Systems for Use in Bacteria and Plants

1996 ◽  
Vol 23 (1) ◽  
pp. 75 ◽  
Author(s):  
SR Mudge ◽  
WR Lewis-Henderson ◽  
RG Birch
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Ccd Camera ◽  
Reporter Gene Expression ◽  
In Vitro Assays ◽  
E Coli ◽  
Cell Extracts ◽  
Cooled Ccd

Luciferase genes from Vibrio harveyi (luxAB) and firefly (luc) were introduced into E. coli, Agrobacteriurn, Arabidopsis and tobacco. Transformed bacteria and plants were quantitatively assayed for luciferase activity using a range of in vitro and in vivo assay conditions. Both lux and luc proved efficient reporter genes in bacteria, although it is important to be aware that the sensitive assays may detect expression due to readthrough from distant promoters. LUX activity was undetectable by liquid nitrogen-cooled CCD camera assays on intact tissues of plants which showed strong luxAB expression by in vitro assays. The decanal substrate for the lux assay was toxic to many plant tissues, and caused chemiluminescence in untransformed Arabidopsis leaves. These are serious limitations to application of the lux system for sensitive, non-toxic assays of reporter gene expression in plants. In contrast, LUC activity was readily detectable in intact tissues of all plants with luc expression detectable by luminometer assays on cell extracts. Image intensities of luc-expressing leaves were commonly two to four orders of magnitude above controls under the CCD camera. Provided adequate penetration of the substrate luciferin is obtained, luc is suitable for applications requiring sensitive, non-toxic assays of reporter gene expression in plants.

scholarly journals PVv3, a New Shuttle Vector for Gene Expression in Vibrio vulnificus

2013 ◽  
Vol 80 (4) ◽  
pp. 1477-1481 ◽  
Author(s):  
Karina Klevanskaa ◽  
Nadja Bier ◽  
Kerstin Stingl ◽  
Eckhard Strauch ◽  
Stefan Hertwig
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Green Fluorescent Protein ◽  
Vibrio Parahaemolyticus ◽  
Fluorescent Protein ◽  
Vibrio Vulnificus ◽  
Shuttle Vector ◽  
Content Type ◽  
E Coli ◽  
Green Fluorescent

ABSTRACTAn efficient electroporation procedure forVibrio vulnificuswas designed using the new cloning vector pVv3 (3,107 bp). Transformation efficiencies up to 2 × 106transformants per μg DNA were achieved. The vector stably replicated in bothV. vulnificusandEscherichia coliand was also successfully introduced intoVibrio parahaemolyticusandVibrio cholerae. To demonstrate the suitability of the vector for molecular cloning, the green fluorescent protein (GFP) gene and thevvhBAhemolysin operon were inserted into the vector and functionally expressed inVibrioandE. coli.

scholarly journals Inducible Suppression of Global Translation by Overuse of Rare Codons

2015 ◽  
Vol 81 (7) ◽  
pp. 2544-2553 ◽  
Author(s):  
Hideki Kobayashi
Keyword(s):  
Gene Expression ◽  
Cancer Cells ◽  
Biological Networks ◽  
Gene Networks ◽  
Fluorescent Protein ◽  
Live Cells ◽  
Control Gene ◽  
Content Type ◽  
E Coli ◽  
Control Gene Expression

ABSTRACTRecently, artificial gene networks have been developed in synthetic biology to control gene expression and make organisms as controllable as robots. Here, I present an artificial posttranslational gene-silencing system based on the codon usage bias and low tRNA content corresponding to minor codons. I engineered the green fluorescent protein (GFP) gene to inhibit translation indirectly with the lowest-usage codons to monopolize various minor tRNAs (lgfp). The expression oflgfpinterfered nonspecifically with the growth ofEscherichia coli,Saccharomyces cerevisiae, human HeLa cervical cancer cells, MCF7 breast cancer cells, and HEK293 kidney cells, as well as phage and adenovirus expansion. Furthermore, insertion oflgfpdownstream of a phage response promoter conferred phage resistance onE. coli. Such engineered gene silencers could act as components of biological networks capable of functioning with suitable promoters inE. coli,S. cerevisiae, and human cells to control gene expression. The results presented here show general suppressor artificial genes for live cells and viruses. This robust system provides a gene expression or cell growth control device for artificially synthesized gene networks.

scholarly journals Engineering yellow fluorescent protein probe for visualization of parallel DNA G-quadruplex

2018 ◽  
Vol 21 (3) ◽  
pp. 84-89 ◽  
Author(s):  
Tuom TT Truong ◽  
Trang PT Phan ◽  
Linh TT Le ◽  
Dung H Nguyen ◽  
Hoang D Nguyen ◽  
...  
Keyword(s):  
Small Molecules ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Biological Processes ◽  
Naked Eye ◽  
High Affinity ◽  
Quadruplex Structure ◽  
G Quadruplex

Introduction: The formation of G-quadruplex plays a key role in many biological processes. Therefore, visualization of G-quadruplex is highly essential for design of G-quadruplex-targeted small molecules (drugs). Herein, we report on an engineered fluorescent protein probe which was able to distinguish G-quadruplex topologies. Methods: The fluorescent protein probe was generated by genetically incorporating yellow fluorescent protein (YFP) to RNA helicase associated with AU-rich element (RHAU) peptide motif. Results: This probe could selectively bind and visualize parallel G-quadruplex structure (T95-2T) at high affinity (Kd~130 nM). Visualization of the parallel G-quadruplex by RHAU-YFP could be easily observed in vitro by using normal Gel Doc or the naked eye. Conclusion: The YFP probe could be encoded in cells to provide a powerful tool for detection of parallel G-quadruplexes both in vitro and in vivo.  

scholarly journals Codon-dependent noise dictates cell-to-cell variability in nutrient poor environments

2018 ◽  
Author(s):  
Enrique Balleza ◽  
Lisa F. Marshall ◽  
J. Mark Kim ◽  
Philippe Cluzel
Keyword(s):  
Amino Acid ◽  
Protein Expression ◽  
Fluorescent Protein ◽  
E Coli ◽  
Expression Noise ◽  
Cell To Cell Variability

Under nutrient-rich conditions, stochasticity of transcription drives protein expression noise. However, by shifting the environment to amino acid-limited conditions, we identified in E. coli a source of noise whose strength is dictated by translational processes. Specifically, we discovered that cell-to-cell variations in fluorescent protein expression depend on codon choice, with codons yielding lower mean expression after amino acid downshift also resulting in greater noise. We propose that ultra-sensitivity in the tRNA charging/discharging cycle shapes the strength of the observed noise by amplifying fluctuations in global intracellular parameters, such as the concentrations of amino acid, synthetase, and tRNA. We hypothesize that this codon-dependent noise may allow bacteria to selectively optimize cell-to-cell variability in poor environments without relying on low molecular numbers.

scholarly journals Genetically-encoded fluorescent biosensor for rapid detection of protein expression

2020 ◽  
Author(s):  
Matthew G Eason ◽  
Antonia T Pandelieva ◽  
Marc M Mayer ◽  
Safwat T Khan ◽  
Hernan G Garcia ◽  
...  
Keyword(s):  
Protein Expression ◽  
Real Time ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Live Cells ◽  
Spatiotemporal Resolution ◽  
E Coli ◽  
Fluorescent Biosensor ◽  
Green Fluorescent

Fluorescent proteins are widely used as fusion tags to detect protein expression in vivo. To become fluorescent, these proteins must undergo chromophore maturation, a slow process with a half-time of 5 to >30 min, which causes delays in real-time detection of protein expression. Here, we engineer a genetically-encoded fluorescent biosensor to enable detection of protein expression within seconds in live cells. This sensor for transiently-expressed proteins (STEP) is based on a fully matured but dim green fluorescent protein in which pre-existing fluorescence increases 11-fold in vivo following the specific and rapid binding of a protein tag (Kd 120 nM, kon 1.7 x 10^5 M-1s-1). In live E. coli cells, our STEP biosensor enables detection of protein expression twice as fast as the use of standard fluorescent protein fusions. Our biosensor opens the door to the real-time study of short-timescale processes in research model animals with high spatiotemporal resolution.

scholarly journals Random Insertion of a TetR-Inducing Peptide Tag into Escherichia coli Proteins Allows Analysis of Protein Levels by Induction of Reporter Gene Expression

2006 ◽  
Vol 72 (8) ◽  
pp. 5637-5642 ◽  
Author(s):  
Maximilian Schlicht ◽  
Christian Berens ◽  
Janko Daam ◽  
Wolfgang Hillen
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Protein Expression ◽  
Reporter Gene ◽  
Expression Patterns ◽  
Reporter Gene Expression ◽  
Published Data ◽  
Insertion Element ◽  
Protein Levels ◽  
Fusion Protein Expression

ABSTRACT The insertion element InsTipα was constructed to generate protein expression data. It randomly fuses the TetR-inducing peptide Tip to the affected reading frame. Fusion protein expression is quantified by Tet-regulated reporter gene expression. The expression patterns of tagged Escherichia coli genes fully agree with published data from transcriptional fusions or microarrays, validating the Tip tag approach.

scholarly journals The Sequence of the Ribosomal Binding Site Controls the Gene Expression in Brucella

2021 ◽  
Author(s):  
Shuang Liu ◽  
Peng Wang ◽  
Yanbo Dong ◽  
Heling Xu ◽  
Shanhu Li ◽  
...  
Keyword(s):  
Protein Expression ◽  
Evaluation System ◽  
Fluorescent Protein ◽  
Polymyxin B ◽  
E Coli ◽  
Sds Page ◽  
Mutant Strains ◽  
Original Goal ◽  
Shine Dalgarno Sequence ◽  
Ribosomal Binding Site

Abstract BackgroundBrucella is an important pathogen causing Brucellosis. Vaccine strains obtained by a single knockout cannot combine low virulence and immunogenicity. Our study modified the SD sequence and spacer sequence of the RBS of Brucella to affect its protein expression. We altered the RBS of LPS-associated genes to reduce LPS-associated protein expression while retaining LPS integrity.ResultsWe first established an evaluation system based on the reporter gene red fluorescent protein mCherry. The mCherry expression could be changed by altering the Shine Dalgarno sequence and spacer sequence of RBS. After optimizing the Shine Dalgarno sequence, mCherry expression was increased 4-fold in E. coli and decreased by 1/4 in Brucella. The mCherry expression was increased 1.5-fold in E. coli and decreased to 1/2 in Brucella when the length of the spacer sequence was 0. When the spacer sequence was NA (N = 4, 8, 12nt) or NG (N = 4, 8, 12nt), mCherry expression was reduced in both E. coli and Brucella. Accordingly, two mutant strains were constructed in an attempt to decrease the expression of LptA and LpxO, Brucella LPS-related genes, by 1/4. Silver staining experiments of LPS SDS-PAGE revealed an alteration in the composition of LPS in the two mutant strains. Polymyxin B experiments revealed that both mutant strains were more sensitive to Polymyxin B resistance.Conclusion: In Brucella, the expression of the target gene could be affected by changing the length or the composition of the RBS sequence. The LPS gene remained unchanged while reducing the expression of its associated protein, achieving the original goal of reducing bacterial virulence while retaining immunogenicity. It is a promising strategy to improve the safety and efficacy of vaccines.

scholarly journals The Protocatechuate 3,4-Dioxygenase Solubility (PCDS) Tag Enhances the Expression and Solubility of Heterogenous Proteins in Escherichia coli

2021 ◽  
Vol 12 ◽  
Author(s):  
Lei Zou ◽  
Sha Li ◽  
Nan Li ◽  
Shi-Long Ruan ◽  
Jing Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Expression ◽  
Heterologous Protein ◽  
Fluorescent Protein ◽  
Recombinant Protein Expression ◽  
Yellow Fluorescent Protein ◽  
Fluorescence Emission ◽  
Soluble Expression ◽  
Heterologous Protein Expression ◽  
E Coli

Escherichia coli has been developed as the most common host for recombinant protein expression. Unfortunately, there are still some proteins that are resistant to high levels of heterologous soluble expression in E. coli. Protein and peptide fusion tags are one of the most important methods for increasing target protein expression and seem to influence the expression efficiency and solubility as well. In this study, we identify a short 15-residue enhancing solubility peptide, the PCDS (protocatechuate 3,4-dioxygenase solubility) tag, which enhances heterologous protein expression in E. coli. This PCDS tag is a 45-bp long sequence encoding a peptide tag involved in the soluble expression of protocatechuate 3,4-dioxygenase, encoded by the pcaHG98 genes of Pseudomonas putida NCIMB 9866. The 45-bp sequence was also beneficial for pcaHG98 gene amplification. This tag was shown to be necessary for the heterologous soluble expression of PcaHG98 in E. coli. Purified His6-PcaHG98e04-PCDS exhibited an activity of 205.63±14.23U/mg against protocatechuate as a substrate, and this activity was not affected by a PCDS tag. This PCDS tag has been fused to the mammalian yellow fluorescent protein (YFP) to construct YFP-PCDS without its termination codons and YFPt-PCDS with. The total protein expressions of YFP-PCDS and YFPt-PCDS were significantly amplified up to 1.6-fold and 2-fold, respectively, compared to YFP alone. Accordingly, His6-YFP-PCDS and His6-YFPt-PCDS had 1.6-fold and 3-fold higher soluble protein yields, respectively, than His6-YFP expressed under the same conditions. His6-YFP, His6-YFP-PCDS, and His6-YFPt-PCDS also showed consistent fluorescence emission spectra, with a peak at 530nm over a scanning range from 400 to 700nm. These results indicated that the use of the PCDS tag is an effective way to improve heterologous protein expression in E. coli.

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