scholarly journals Stable integration of an optimized inducible promoter system enables spatiotemporal control of gene expression throughout avian development

2020 ◽  
Author(s):  
Daniel Chu ◽  
An Nguyen ◽  
Spenser S. Smith ◽  
Zuzana Vavrušová ◽  
Richard A. Schneider

AbstractPrecisely altering gene expression is critical for understanding molecular processes of embryogenesis. Although some tools exist for transgene misexpression in developing chick embryos, we have refined and advanced them by simplifying and optimizing constructs for spatiotemporal control. To maintain expression over the entire course of embryonic development we use an enhanced piggyBac transposon system that efficiently integrates sequences into the host genome. We also incorporate a DNA targeting sequence to direct plasmid translocation into the nucleus and a D4Z4 insulator sequence to prevent epigenetic silencing. We designed these constructs to minimize their size and maximize cellular uptake, and to simplify usage by placing all of the integrating sequences on a single plasmid. Following electroporation of stage HH8.5 embryos, our tetracycline-inducible promoter construct produces robust transgene expression in the presence of doxycycline at any point during embryonic development in ovo or in culture. Moreover, expression levels can be modulated by titrating doxycycline concentrations and spatial control can be achieved using beads or gels. Thus, we have generated a novel, sensitive, tunable, and stable inducible-promoter system for high-resolution gene manipulation in vivo.

Biology Open ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. bio055343 ◽  
Author(s):  
Daniel Chu ◽  
An Nguyen ◽  
Spenser S. Smith ◽  
Zuzana Vavrušová ◽  
Richard A. Schneider

ABSTRACTPrecisely altering gene expression is critical for understanding molecular processes of embryogenesis. Although some tools exist for transgene misexpression in developing chick embryos, we have refined and advanced them by simplifying and optimizing constructs for spatiotemporal control. To maintain expression over the entire course of embryonic development we use an enhanced piggyBac transposon system that efficiently integrates sequences into the host genome. We also incorporate a DNA targeting sequence to direct plasmid translocation into the nucleus and a D4Z4 insulator sequence to prevent epigenetic silencing. We designed these constructs to minimize their size and maximize cellular uptake, and to simplify usage by placing all of the integrating sequences on a single plasmid. Following electroporation of stage HH8.5 embryos, our tetracycline-inducible promoter construct produces robust transgene expression in the presence of doxycycline at any point during embryonic development in ovo or in culture. Moreover, expression levels can be modulated by titrating doxycycline concentrations and spatial control can be achieved using beads or gels. Thus, we have generated a novel, sensitive, tunable, and stable inducible-promoter system for high-resolution gene manipulation in vivo.


2016 ◽  
Author(s):  
Makoto J. Ohira ◽  
David G. Hendrickson ◽  
R. Scott McIsaac ◽  
Nicholas Rhind

ABSTRACTThe fission yeast Schizosaccharomyces pombe lacks a diverse toolkit of inducible promoters for experimental manipulation. Available inducible promoters suffer from slow induction kinetics, limited control of expression levels and/or a requirement for defined growth medium. In particular, no S. pombe inducible promoter systems exhibit a linear dose response, which would allow expression to be tuned to specific levels. We have adapted a fast, orthogonal promoter system with a large dynamic range and a linear dose response, based on β-estradiol-regulated function of the human estrogen receptor, for use in S. pombe. We show that this promoter system, termed Z3EV, turns on quickly, can reach a maximal induction of 20 fold, and exhibits a linear dose response over its entire induction range, with few off target effects. We demonstrate the utility of this system by regulating the mitotic inhibitor Wee1 to create a strain in which cell size is regulated by β-estradiol concentration. This promoter system will be of great utility for experimentally regulating gene expression in fission yeast.


Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 198-205 ◽  
Author(s):  
Marc Breton ◽  
Evelyne Sagné ◽  
Sybille Duret ◽  
Laure Béven ◽  
Christine Citti ◽  
...  

Inducible promoter systems are powerful tools for studying gene function in prokaryotes but have never been shown to function in mollicutes. In this study we evaluated the efficacy of the tetracycline-inducible promoter Pxyl/tetO2 from Bacillus subtilis in controlling gene expression in two mollicutes, the plant pathogen Spiroplasma citri and the animal pathogen Mycoplasma agalactiae. An S. citri plasmid carrying the spiralin gene under the control of the xyl/tetO2 tetracycline-inducible promoter and the TetR repressor gene under the control of a constitutive spiroplasmal promoter was introduced into the spiralin-less S. citri mutant GII3-9a3. In the absence of tetracycline, expression of TetR almost completely abolished expression of spiralin from the xyl/tetO2 promoter. Adding tetracycline (>50 ng ml−1) to the medium induced high-level expression of spiralin. Interestingly, inducible expression of spiralin was also detected in vivo: in S. citri-infected leafhoppers fed on tetracycline-containing medium and in S. citri-infected plants watered with tetracycline. A similar construct was introduced into the M. agalactiae chromosome through transposition. Tetracycline-induced expression of spiralin proved the TetR-Pxyl/tetO2 system to be functional in the ruminant pathogen, suggesting that this tetracycline-inducible promoter system might be of general use in mollicutes.


Radiology ◽  
2011 ◽  
Vol 258 (2) ◽  
pp. 496-504 ◽  
Author(s):  
Omer F. Eker ◽  
Bruno Quesson ◽  
Claire Rome ◽  
Josette Arsaut ◽  
Colette Deminière ◽  
...  

2021 ◽  
Vol 4 (1) ◽  
pp. 22
Author(s):  
Mrinmoyee Majumder ◽  
Viswanathan Palanisamy

Control of gene expression is critical in shaping the pro-and eukaryotic organisms’ genotype and phenotype. The gene expression regulatory pathways solely rely on protein–protein and protein–nucleic acid interactions, which determine the fate of the nucleic acids. RNA–protein interactions play a significant role in co- and post-transcriptional regulation to control gene expression. RNA-binding proteins (RBPs) are a diverse group of macromolecules that bind to RNA and play an essential role in RNA biology by regulating pre-mRNA processing, maturation, nuclear transport, stability, and translation. Hence, the studies aimed at investigating RNA–protein interactions are essential to advance our knowledge in gene expression patterns associated with health and disease. Here we discuss the long-established and current technologies that are widely used to study RNA–protein interactions in vivo. We also present the advantages and disadvantages of each method discussed in the review.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Benjamin H. Weinberg ◽  
Jang Hwan Cho ◽  
Yash Agarwal ◽  
N. T. Hang Pham ◽  
Leidy D. Caraballo ◽  
...  

Abstract Site-specific DNA recombinases are important genome engineering tools. Chemical- and light-inducible recombinases, in particular, enable spatiotemporal control of gene expression. However, inducible recombinases are scarce due to the challenge of engineering high performance systems, thus constraining the sophistication of genetic circuits and animal models that can be created. Here we present a library of >20 orthogonal inducible split recombinases that can be activated by small molecules, light and temperature in mammalian cells and mice. Furthermore, we engineer inducible split Cre systems with better performance than existing systems. Using our orthogonal inducible recombinases, we create a genetic switchboard that can independently regulate the expression of 3 different cytokines in the same cell, a tripartite inducible Flp, and a 4-input AND gate. We quantitatively characterize the inducible recombinases for benchmarking their performances, including computation of distinguishability of outputs. This library expands capabilities for multiplexed mammalian gene expression control.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Emma L Robinson ◽  
Syed Haider ◽  
Hillary Hei ◽  
Richard T Lee ◽  
Roger S Foo

Heart failure comprises of clinically distinct inciting causes but a consistent pattern of change in myocardial gene expression supports the hypothesis that unifying biochemical mechanisms underlie disease progression. The recent RNA-seq revolution has enabled whole transcriptome profiling, using deep-sequencing technologies. Up to 70% of the genome is now known to be transcribed into RNA, a significant proportion of which is long non-coding RNAs (lncRNAs), defined as polyribonucleotides of ≥200 nucleotides. This project aims to discover whether the myocardium expression of lncRNAs changes in the failing heart. Paired end RNA-seq from a 300-400bp library of ‘stretched’ mouse myocyte total RNA was carried out to generate 76-mer sequence reads. Mechanically stretching myocytes with equibiaxial stretch apparatus mimics pathological hypertrophy in the heart. Transcripts were assembled and aligned to reference genome mm9 (UCSC), abundance determined and differential expression of novel transcripts and alternative splice variants were compared with that of control (non-stretched) mouse myocytes. Five novel transcripts have been identified in our RNA-seq that are differentially expressed in stretched myocytes compared with non-stretched. These are regions of the genome that are currently unannotated and potentially are transcribed into non-coding RNAs. Roles of known lncRNAs include control of gene expression, either by direct interaction with complementary regions of the genome or association with chromatin remodelling complexes which act on the epigenome.Changes in expression of genes which contribute to the deterioration of the failing heart could be due to the actions of these novel lncRNAs, immediately suggesting a target for new pharmaceuticals. Changes in the expression of these novel transcripts will be validated in a larger sample size of stretched myocytes vs non-stretched myocytes as well as in the hearts of transverse aortic constriction (TAC) mice vs Sham (surgical procedure without the aortic banding). In vivo investigations will then be carried out, using siLNA antisense technology to silence novel lncRNAs in mice.


2020 ◽  
Author(s):  
Jake D. Callaghan ◽  
Nicholas A. Stella ◽  
Kara M. Lehner ◽  
Benjamin R. Treat ◽  
Kimberly M. Brothers ◽  
...  

ABSTRACTTunable control of gene expression is an invaluable tool for biological experiments. In this study, we describe a new xylose-inducible promoter system and evaluate it in both Pseudomonas aeruginosa and P. fluorescens. The Pxut promoter derived from the P. flurorescens xut operon was incorporated into a broad host-range pBBR1-based plasmid and compared to the Escherichia coli-derived PBAD promoter using gfp as a reporter. GFP-fluorescence from the Pxut promoter was inducible in both Pseudomonas species, but not in E. coli, which may facilitate cloning of toxic genes using E. coli to generate plasmids. The Pxut promoter was expressed at a lower inducer concentration than PBAD in P. fluorescens and higher gfp levels were achieved using Pxut. Flow cytometry analysis indicated that Pxut was more leaky than PBAD in the tested Pseudomonas species, but was expressed in a higher proportion of cells when induced. D-xylose did not support growth of P. aeruginosa or P. fluorescens as a sole carbon source and is less expensive than many other commonly used inducers which could facilitate large scale applications. The efficacy of this system aided in demonstrating a role for the P. aeruginosa type II secretion system gene from xcpQ in bacterial inhibition of corneal epithelial cell wound closure. This study introduces a new inducible promoter system for gene expression for use in Pseudomonas species.ImportancePseudomonas species are enormously important in human infections, biotechnology, and as a model system for interrogating basic science questions. In this study we have developed a xylose-inducible promoter system and evaluated it in P. aeruginosa and P. fluorescens and found it to be suitable for the strong induction of gene expression. Furthermore, we have demonstrated its efficacy in controlled gene expression to show that a type 2 secretion system protein from P. aeruginosa, XcpQ, is important for host-pathogen interactions in a corneal wound closure model.


2019 ◽  
Author(s):  
Prasad U. Bandodkar ◽  
Hadel Al Asafen ◽  
Gregory T. Reeves

AbstractA feed forward loop (FFL) is commonly observed in several biological networks. The FFL network motif has been mostly been studied with respect to variation of the input signal in time, with only a few studies of FFL activity in a spatially distributed system such as morphogen-mediated tissue patterning. However, most morphogen gradients also evolve in time. We studied the spatiotemporal behavior of a coherent FFL in two contexts: (1) a generic, oscillating morphogen gradient and (2) the dorsal-ventral patterning of the early Drosophila embryo by a gradient of the NF-κB homolog Dorsal with its early target Twist. In both models, we found features in the dynamics of the intermediate node – phase difference and noise filtering – that were largely independent of the parameterization of the models, and thus were functions of the structure of the FFL itself. In the Dorsal gradient model, we also found that the dynamics of Dorsal require maternal pioneering factor Zelda for proper target gene expression.


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