scholarly journals Development and Application of an Insertional System for Gene Delivery and Expression in Campylobacter jejuni

2005 ◽  
Vol 71 (7) ◽  
pp. 4004-4013 ◽  
Author(s):  
A. V. Karlyshev ◽  
B. W. Wren
Keyword(s):  
Gene Delivery ◽  
Campylobacter Jejuni ◽  
Fluorescent Protein ◽  
Gene Clusters ◽  
Target Cells ◽  
Rrna Gene ◽  
Efficient System ◽  
Universal Procedure ◽  
Species Specific ◽  
Green Fluorescent

ABSTRACT The genetic investigation of Campylobacter jejuni, an important gastrointestinal pathogen, has been hampered by the lack of an efficient system for introduction of exogenous genetic information, as commonly used vectors designed for Escherichia coli and other bacteria cannot be maintained in Campylobacter cells. Additionally, gene expression in Campylobacter requires the presence of species-specific promoters. In this study we exploited the availability of several conserved copies of rRNA gene clusters for insertion of various genes into the chromosome by homologous recombination. The high conservation of the rRNA sequences means that the procedure can be applied to other Campylobacter strains. The presence of a Campylobacter-derived promoter in this vector ensures expression of exogenous genes in target cells. The efficiency of the procedure was demonstrated by complementation of mutations in two strains of Campylobacter. In addition, we applied the system for introduction and expression of a green fluorescent protein (GFP). GFP-expressing Campylobacter allowed visualization of sessile bacteria attached to a glass surface in stationary liquid culture. The study demonstrated that the attached bacteria contained an assemblage of coccoid and spiral forms with liquid channels preserving viable highly motile cells. We demonstrate a novel universal procedure for gene delivery and expression that can be used as an efficient tool to study this poorly understood pathogen. The principles developed in this study could be more widely applied for the manipulation of other bacteria that are refractory to genetic analysis.

scholarly journals Delivery of Bioactive Gene Particles via Gelatin-Collagen-PEG-Based Electrospun Matrices

2021 ◽  
Vol 14 (7) ◽  
pp. 666
Author(s):  
Eleni Tsekoura ◽  
Porntipa Pankongadisak ◽  
Daniel Graf ◽  
Yaman Boluk ◽  
Hasan Uludağ
Keyword(s):  
Gene Delivery ◽  
Fluorescent Protein ◽  
Transfection Efficiency ◽  
Electrospun Fiber ◽  
C2c12 Cells ◽  
Bone Morphogenetic Protein 2 ◽  
Target Cells ◽  
Fiber Mats ◽  
Mouse Osteoblast ◽  
Green Fluorescent

The fabrication of fiber mats via electrospinning has been adopted in the last decades to produce high quality scaffolds for tissue engineering. However, an effective combination of electrospinning methods with gene delivery therapies remains a challenge. In this study, we describe how the delivery of gene complexes via electrospun mats that contain different volumes of gelatin (Gel), collagen (Col), and polyethylene glycol (PEG) can affect gene expression by transfected cells. Non-viral complexes were formulated by using lipid modified polyethylenimine (PEI) polymer and plasmid DNAs (pDNA) like the reporter Green Fluorescent Protein (GFP) and the therapeutically relevant Bone Morphogenetic Protein-2 (BMP-2) and electrospuned after being mixed with different volumes of Gel-Col-PEG mats and delivered to human myoblast (C2C12) and mouse osteoblast cells (MC3T3). The entrapment of GFP complexes via different homogeneous electrospun fiber mats revealed that a high fraction of collagen in the mats affected the quality of the fibers and led to reduced transfection efficiency on target cells. On the other hand, the fabrication of double-layered mats that contained collagen without complexes as a first layer and gelatin-collagen-PEG with complexes as a second layer successfully induced GFP expression and ALP activity in C2C12 cells. We conclude that this study has established the advantage of formulating multilayered bioactive collagen-based mats for gene delivery applications.

scholarly journals Systemic AAV6-synapsin-GFP administration results in lower liver biodistribution, compared to AAV1&2 and AAV9, with neuronal expression following ultrasound-mediated brain delivery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Danielle Weber-Adrian ◽  
Rikke Hahn Kofoed ◽  
Joseph Silburt ◽  
Zeinab Noroozian ◽  
Kairavi Shah ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Intravenous Injection ◽  
Viral Vectors ◽  
Focused Ultrasound ◽  
Fluorescent Protein ◽  
Gfp Expression ◽  
Peripheral Organs ◽  
Neuronal Expression ◽  
Green Fluorescent ◽  
The Brain

AbstractNon-surgical gene delivery to the brain can be achieved following intravenous injection of viral vectors coupled with transcranial MRI-guided focused ultrasound (MRIgFUS) to temporarily and locally permeabilize the blood–brain barrier. Vector and promoter selection can provide neuronal expression in the brain, while limiting biodistribution and expression in peripheral organs. To date, the biodistribution of adeno-associated viruses (AAVs) within peripheral organs had not been quantified following intravenous injection and MRIgFUS delivery to the brain. We evaluated the quantity of viral DNA from the serotypes AAV9, AAV6, and a mosaic AAV1&2, expressing green fluorescent protein (GFP) under the neuron-specific synapsin promoter (syn). AAVs were administered intravenously during MRIgFUS targeting to the striatum and hippocampus in mice. The syn promoter led to undetectable levels of GFP expression in peripheral organs. In the liver, the biodistribution of AAV9 and AAV1&2 was 12.9- and 4.4-fold higher, respectively, compared to AAV6. The percentage of GFP-positive neurons in the FUS-targeted areas of the brain was comparable for AAV6-syn-GFP and AAV1&2-syn-GFP. In summary, MRIgFUS-mediated gene delivery with AAV6-syn-GFP had lower off-target biodistribution in the liver compared to AAV9 and AAV1&2, while providing neuronal GFP expression in the striatum and hippocampus.

scholarly journals Focal Distribution of Baculovirus IE1 Triggered by Its Binding to the hr DNA Elements

2005 ◽  
Vol 79 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Toshihiro Nagamine ◽  
Yu Kawasaki ◽  
Tetsutaro Iizuka ◽  
Shogo Matsumoto
Keyword(s):  
Fluorescent Protein ◽  
Direct Repeat ◽  
Single Copy ◽  
Targeted Mutagenesis ◽  
Homologous Region ◽  
Focus Formation ◽  
Primary Determinant ◽  
Dna Elements ◽  
Species Specific ◽  
Green Fluorescent

ABSTRACT In BmN cells infected with the baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV), IE1, a principal transcriptional activator, localizes to sites of viral DNA replication. IE1 initially displays focal distribution in BmNPV-infected cells prior to DNA synthesis, whereas the protein expressed by transfection with the ie1 gene is distributed throughout the nucleoplasm instead of localized to discrete subnuclear structures. To identify the inducer of focus formation for IE1, we conducted transfection experiments with an IE1-GFP construct and found that cotransfection with genomic DNA fragments bearing the homologous region (hr) sequences caused the formation of IE1-green fluorescent protein (GFP) foci. The transfection of insect cells with a single plasmid containing exclusively the hr3 sequence and the IE1-GFP gene was sufficient to form IE1-GFP foci. These results suggest that hr elements are a primary determinant of the focal distribution of IE1. An analysis of a series of hr3 deletion mutants showed that a single copy of the direct repeat could induce the formation of IE1 foci. Targeted mutagenesis within the hr-binding domain of IE1-GFP caused impairment of the hr-dependent IE1 localization, suggesting that binding of IE1 to the hr elements is essential for the onset of IE1 focus formation. The observation of BmNPV IE1 foci in non-BmNPV-susceptible cells suggests that no species-specific factors are required for hr-dependent IE1 focus formation.

scholarly journals Nucleofection Efficiency of Sheep Primary Fibroblasts Established from Refrigerated Skin

2018 ◽  
Vol 10 (4) ◽  
pp. 12
Author(s):  
Mahipal Singh ◽  
Xiaoling Ma
Keyword(s):  
Fluorescent Protein ◽  
Transfection Efficiency ◽  
Genetically Engineered ◽  
Dermal Fibroblasts ◽  
Biologically Active ◽  
Cell Type ◽  
Gfp Expression ◽  
Primary Fibroblasts ◽  
Species Specific ◽  
Green Fluorescent

Dermal fibroblasts are useful for production of genetically engineered biologically active factors for development of cellular therapies and tissue engineering products for regenerative medicine. However, their transfection efficiencies using traditional non-viral methods are low and vary based on cell-type and species-specific differences. Using nucleofection technology, here we show that the transfection efficiency of primary fibroblasts established after 0-, 35-, and 65-days of postmortem storage of sheep skin tissues in a refrigerator was 59.49 % ± 9.66 %, 59.33 % ± 11.59 %, and 43.48 % ± 8.09 % respectively, as determined by analysis of green fluorescent protein (GFP) expression. 

scholarly journals Live-Attenuated Measles Virus Vaccine Targets Dendritic Cells and Macrophages in Muscle of Nonhuman Primates

2014 ◽  
Vol 89 (4) ◽  
pp. 2192-2200 ◽  
Author(s):  
Linda J. Rennick ◽  
Rory D. de Vries ◽  
Thomas J. Carsillo ◽  
Ken Lemon ◽  
Geert van Amerongen ◽  
...  
Keyword(s):  
Measles Virus ◽  
Nonhuman Primates ◽  
Enhanced Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Vaccine Virus ◽  
Target Cells ◽  
Recombinant Viruses ◽  
Green Fluorescent

ABSTRACTAlthough live-attenuated measles virus (MV) vaccines have been used successfully for over 50 years, the target cells that sustain virus replicationin vivoare still unknown. We generated a reverse genetics system for the live-attenuated MV vaccine strain Edmonston-Zagreb (EZ), allowing recovery of recombinant (r)MVEZ. Three recombinant viruses were generated that contained the open reading frame encoding enhanced green fluorescent protein (EGFP) within an additional transcriptional unit (ATU) at various positions within the genome. rMVEZEGFP(1), rMVEZEGFP(3), and rMVEZEGFP(6) contained the ATU upstream of the N gene, following the P gene, and following the H gene, respectively. The viruses were comparedin vitroby growth curves, which indicated that rMVEZEGFP(1) was overattenuated. Intratracheal infection of cynomolgus macaques with these recombinant viruses revealed differences in immunogenicity. rMVEZEGFP(1) and rMVEZEGFP(6) did not induce satisfactory serum antibody responses, whereas bothin vitroandin vivorMVEZEGFP(3) was functionally equivalent to the commercial MVEZ-containing vaccine. Intramuscular vaccination of macaques with rMVEZEGFP(3) resulted in the identification of EGFP+cells in the muscle at days 3, 5, and 7 postvaccination. Phenotypic characterization of these cells demonstrated that muscle cells were not infected and that dendritic cells and macrophages were the predominant target cells of live-attenuated MV.IMPORTANCEEven though MV strain Edmonston-Zagreb has long been used as a live-attenuated vaccine (LAV) to protect against measles, nothing is known about the primary cells in which the virus replicatesin vivo. This is vital information given the push to move toward needle-free routes of vaccination, since vaccine virus replication is essential for vaccination efficacy. We have generated a number of recombinant MV strains expressing enhanced green fluorescent protein. The virus that best mimicked the nonrecombinant vaccine virus was formulated according to protocols for production of commercial vaccine virus batches, and was subsequently used to assess viral tropism in nonhuman primates. The virus primarily replicated in professional antigen-presenting cells, which may explain why this LAV is so immunogenic and efficacious.

scholarly journals Canine Distemper Virus Uses both the Anterograde and the Hematogenous Pathway for Neuroinvasion

2006 ◽  
Vol 80 (19) ◽  
pp. 9361-9370 ◽  
Author(s):  
Penny A. Rudd ◽  
Roberto Cattaneo ◽  
Veronika von Messling
Keyword(s):  
Measles Virus ◽  
Canine Distemper Virus ◽  
Fluorescent Protein ◽  
Early Time ◽  
Olfactory Nerve ◽  
The Body ◽  
Target Cells ◽  
Canine Distemper ◽  
Invasion Routes ◽  
Green Fluorescent

ABSTRACT Canine distemper virus (CDV), a member of the Morbillivirus genus that also includes measles virus, frequently causes neurologic complications, but the routes and timing of CDV invasion of the central nervous system (CNS) are poorly understood. To characterize these events, we cloned and sequenced the genome of a neurovirulent CDV (strain A75/17) and produced an infectious cDNA that expresses the green fluorescent protein. This virus fully retained its virulence in ferrets: the course and signs of disease were equivalent to those of the parental isolate. We observed CNS invasion through two distinct pathways: anterogradely via the olfactory nerve and hematogenously through the choroid plexus and cerebral blood vessels. CNS invasion only occurred after massive infection of the lymphatic system and spread to the epithelial cells throughout the body. While at early time points, mostly immune and endothelial cells were infected, the virus later spread to glial cells and neurons. Together, the results suggest similarities in the timing, target cells, and CNS invasion routes of CDV, members of the Morbillivirus genus, and even other neurovirulent paramyxoviruses like Nipah and mumps viruses.

scholarly journals Heterologous downregulation of vasopressin type 2 receptor is induced by transferrin

2013 ◽  
Vol 304 (5) ◽  
pp. F553-F564 ◽  
Author(s):  
Richard Bouley ◽  
Paula Nunes ◽  
Billy Andriopoulos ◽  
Margaret McLaughlin ◽  
Matthew J. Webber ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Dominant Negative ◽  
Target Cells ◽  
Intracellular Camp ◽  
Coated Pits ◽  
Parathyroid Hormone Receptor ◽  
Body Fluid Homeostasis ◽  
Green Fluorescent ◽  
G Protein Coupled

Vasopressin (VP) binds to the vasopressin type 2 receptor (V2R) to trigger physiological effects including body fluid homeostasis and blood pressure regulation. Signaling is terminated by receptor downregulation involving clathrin-mediated endocytosis and V2R degradation. We report here that both native and epitope-tagged V2R are internalized from the plasma membrane of LLC-PK1 kidney epithelial cells in the presence of another ligand, transferrin (Tf). The presence of iron-saturated Tf (holo-Tf; 4 h) reduced V2R binding sites at the cell surface by up to 33% while iron-free (apo-Tf) had no effect. However, no change in green fluorescent protein-tagged V2R distribution was observed in the presence of bovine serum albumin, atrial natriuretic peptide, or ANG II. Conversely, holo-Tf did not induce the internalization of another G protein-coupled receptor, the parathyroid hormone receptor. In contrast to the effect of VP, Tf did not increase intracellular cAMP or modify aquaporin-2 distribution in these cells, although addition of VP and Tf together augmented VP-induced V2R internalization. Tf receptor coimmunoprecipitated with V2R, suggesting that they interact closely, which may explain the additive effect of VP and Tf on V2R endocytosis. Furthermore, Tf-induced V2R internalization was abolished in cells expressing a dominant negative dynamin (K44A) mutant, indicating the involvement of clathrin-coated pits. We conclude that Tf can induce heterologous downregulation of the V2R and this might desensitize VP target cells without activating downstream V2R signaling events. It also provides new insights into urine-concentrating defects observed in rat models of hemochromatosis.

scholarly journals GLUT4 vesicle dynamics in living 3T3 L1 adipocytes visualized with green-fluorescent protein

1997 ◽  
Vol 327 (3) ◽  
pp. 637-642 ◽  
Author(s):  
B. Paru OATEY ◽  
David H. J. VAN WEERING ◽  
P. Stephen DOBSON ◽  
W. Gwyn GOULD ◽  
Jeremy M. TAVARÉ
Keyword(s):  
Plasma Membrane ◽  
Green Fluorescent Protein ◽  
Glucose Transporter ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
Target Cells ◽  
Green Fluorescent ◽  
Vesicle Movement ◽  
Vesicular Compartment ◽  
Intracellular Structure

Insulin stimulates glucose uptake into its target cells by a process which involves the translocation of the GLUT4 isoform of glucose transporter from an intracellular vesicular compartment(s) to the plasma membrane. The step(s) at which insulin acts in the vesicle trafficking pathway (e.g. vesicle movement or fusion with the plasma membrane) is not known. We expressed a green-fluorescent protein-GLUT4 (GFP-GLUT4) chimaera in 3T3 L1 adipocytes. The chimaera was expressed in vesicles located throughout the cytoplasm and also close to the plasma membrane. Insulin promoted a substantial translocation of GFP-GLUT4 to the plasma membrane. Time-lapse confocal microscopy demonstrated that the majority of GFP-GLUT4-containing vesicles in the basal state were relatively static, as if tethered (or attached) to an intracellular structure. A proportion (approx. 5%) of the vesicles spontaneously lost their tether, and were observed to move rapidly within the cell. Other vesicles appear to be tethered only on one edge and were observed in a rapid stretching motion. The data support a model in which GLUT4-containing vesicles are tightly tethered to an intracellular structure(s), and indicate that a primary site of insulin action must be to release these vesicles, allowing them to then translocate to and fuse with the plasma membrane.

scholarly journals Exploiting a precise design of universal synthetic modular regulatory elements to unlock the microbial natural products in Streptomyces

2015 ◽  
Vol 112 (39) ◽  
pp. 12181-12186 ◽  
Author(s):  
Chaoxian Bai ◽  
Yang Zhang ◽  
Xuejin Zhao ◽  
Yiling Hu ◽  
Sihai Xiang ◽  
...  
Keyword(s):  
Quantitative Method ◽  
Fluorescent Protein ◽  
Single Cells ◽  
Gene Clusters ◽  
Regulatory Elements ◽  
Streptomyces Avermitilis ◽  
Systems Biotechnology ◽  
Synthetic Promoters ◽  
Expression Of Genes ◽  
Green Fluorescent

There is a great demand for precisely quantitating the expression of genes of interest in synthetic and systems biotechnology as new and fascinating insights into the genetics of streptomycetes have come to light. Here, we developed, for the first time to our knowledge, a quantitative method based on flow cytometry and a superfolder green fluorescent protein (sfGFP) at single-cell resolution in Streptomyces. Single cells of filamentous bacteria were obtained by releasing the protoplasts from the mycelium, and the dead cells could be distinguished from the viable ones by propidium iodide (PI) staining. With this sophisticated quantitative method, some 200 native or synthetic promoters and 200 ribosomal binding sites (RBSs) were characterized in a high-throughput format. Furthermore, an insulator (RiboJ) was recruited to eliminate the interference between promoters and RBSs and improve the modularity of regulatory elements. Seven synthetic promoters with gradient strength were successfully applied in a proof-of-principle approach to activate and overproduce the cryptic lycopene in a predictable manner in Streptomyces avermitilis. Our work therefore presents a quantitative strategy and universal synthetic modular regulatory elements, which will facilitate the functional optimization of gene clusters and the drug discovery process in Streptomyces.

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