In-Depth Characterization of a Mifepristone-Regulated Expression System for AAV5-Mediated Gene Therapy in the Liver

ABSTRACTA xylose-inducible gene expression vector forClostridium perfringenswas developed. Plasmid pXCH contains a chromosomal region fromClostridium difficile(xylR-PxylB):xylR, encoding the xylose repressor,xylO, thexyloperator sequence, and PxylB, the divergent promoter upstream ofxylBAencoding xylulo kinase and xylose isomerase. pXCH allows tightly regulated expression of the chloramphenicol acetyltransferase reporter and the α-toxin genes in response to the inducer concentration. Thus, pXCH could constitute a new valuable genetic tool for study ofC. perfringens.

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Non-Viral Vectors for Gene Delivery

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681208666180110154233 ◽

2018 ◽

Vol 9 (1) ◽

pp. 4-11 ◽

Cited By ~ 5

Author(s):

Aparna Bansal ◽

Himanshu

Keyword(s):

Gene Therapy ◽

Viral Vectors ◽

Transfection Efficiency ◽

Gene Transfection ◽

Expression System ◽

Target Cells ◽

Specific Expression ◽

Naked Dna

Introduction: Gene therapy has emerged out as a promising therapeutic pave for the treatment of genetic and acquired diseases. Gene transfection into target cells using naked DNA is a simple and safe approach which has been further improved by combining vectors or gene carriers. Both viral and non-viral approaches have achieved a milestone to establish this technique, but non-viral approaches have attained a significant attention because of their favourable properties like less immunotoxicity and biosafety, easy to produce with versatile surface modifications, etc. Literature is rich in evidences which revealed that undoubtedly, non–viral vectors have acquired a unique place in gene therapy but still there are number of challenges which are to be overcome to increase their effectiveness and prove them ideal gene vectors. Conclusion: To date, tissue specific expression, long lasting gene expression system, enhanced gene transfection efficiency has been achieved with improvement in delivery methods using non-viral vectors. This review mainly summarizes the various physical and chemical methods for gene transfer in vitro and in vivo.

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Harnessing a Transient Gene Expression System in Nicotiana benthamiana to Explore Plant Agrochemical Transporters

Plants ◽

10.3390/plants10030524 ◽

2021 ◽

Vol 10 (3) ◽

pp. 524

Author(s):

Bingqi Wu ◽

Zhiting Chen ◽

Xiaohui Xu ◽

Ronghua Chen ◽

Siwei Wang ◽

...

Keyword(s):

Gene Expression ◽

Transient Expression ◽

Nicotiana Benthamiana ◽

Heterologous Gene Expression ◽

Expression System ◽

Functional Characterization ◽

Transient Gene Expression ◽

High Mobility ◽

Gene Expression System

Functional characterization of plant agrichemical transporters provided an opportunity to discover molecules that have a high mobility in plants and have the potential to increase the amount of pesticides reaching damage sites. Agrobacterium-mediated transient expression in tobacco is simple and fast, and its protein expression efficiency is high; this system is generally used to mediate heterologous gene expression. In this article, transient expression of tobacco nicotine uptake permease (NtNUP1) and rice polyamine uptake transporter 1 (OsPUT1) in Nicotiana benthamiana was performed to investigate whether this system is useful as a platform for studying the interactions between plant transporters and pesticides. The results showed that NtNUP1 increases nicotine uptake in N. benthamiana foliar discs and protoplasts, indicating that this transient gene expression system is feasible for studying gene function. Moreover, yeast expression of OsPUT1 apparently increases methomyl uptake. Overall, this method of constructing a transient gene expression system is useful for improving the efficiency of analyzing the functions of plant heterologous transporter-encoding genes and revealed that this system can be further used to study the functions of transporters and pesticides, especially their interactions.

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Bombyx mori Pupae Efficiently Produce Recombinant AAV2/HBoV1 Vectors with a Bombyx mori Nuclear Polyhedrosis Virus Expression System

Viruses ◽

10.3390/v13040704 ◽

2021 ◽

Vol 13 (4) ◽

pp. 704

Author(s):

Qian Yu ◽

Pengfei Chang ◽

Xiaoxuan Liu ◽

Peng Lü ◽

Qi Tang ◽

...

Keyword(s):

Gene Therapy ◽

Bombyx Mori ◽

Nuclear Polyhedrosis Virus ◽

Expression System ◽

Efficient Production ◽

Human Bocavirus ◽

Adeno Associated Virus ◽

Silkworm Pupae ◽

Polyhedrosis Virus ◽

Nuclear Polyhedrosis

Recombinant adeno-associated virus (AAV) vectors have broad application prospects in the field of gene therapy. The establishment of low-cost and large-scale manufacturing is now the general agenda for industry. The baculovirus-insect cell/larva expression system has great potential for these applications due to its scalability and predictable biosafety. To establish a more efficient production system, Bombyx mori pupae were used as a new platform and infected with recombinant Bombyx mori nuclear polyhedrosis virus (BmNPV). The production of a chimeric recombinant adeno-associated virus (rAAV) serotype 2/human bocavirus type-1 (HBoV1) vector was used to evaluate the efficiency of this new baculovirus expression vector (BEV)–insect expression system. For this purpose, we constructed two recombinant BmNPVs, which were named rBmNPV/AAV2Rep-HBoV1Cap and rBmNPV/AAV2ITR-eGFP. The yields of rAAV2/HBoV1 derived from the rBmNPV/AAV2Rep-HBoV1Cap and rBmNPV/AAV2ITR-eGFP co-infected BmN cells exceeded 2 × 104 vector genomes (VG) per cell. The rBmNPV/AAV2Rep-HBoV1Cap and rBmNPV/AAV2ITR-eGFP can express stably for at least five passages. Significantly, rAAV2/HBoV1 could be efficiently generated from BmNPV-infected silkworm larvae and pupae at average yields of 2.52 × 1012 VG/larva and 4.6 × 1012 VG/pupa, respectively. However, the vectors produced from the larvae and pupae had a high percentage of empty particles, which suggests that further optimization is required for this platform in the future. Our work shows that silkworm pupae, as an efficient bioreactor, have great potential for application in the production of gene therapy vectors.

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Functional expression of the eukaryotic proton pump rhodopsin OmR2 in Escherichia coli and its photochemical characterization

Scientific Reports ◽

10.1038/s41598-021-94181-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Masuzu Kikuchi ◽

Keiichi Kojima ◽

Shin Nakao ◽

Susumu Yoshizawa ◽

Shiho Kawanishi ◽

...

Keyword(s):

Escherichia Coli ◽

Proton Pump ◽

Expression System ◽

Spectroscopic Characterization ◽

Functional Expression ◽

Proton Pumping ◽

E Coli ◽

Oxyrrhis Marina ◽

Domains Of Life

AbstractMicrobial rhodopsins are photoswitchable seven-transmembrane proteins that are widely distributed in three domains of life, archaea, bacteria and eukarya. Rhodopsins allow the transport of protons outwardly across the membrane and are indispensable for light-energy conversion in microorganisms. Archaeal and bacterial proton pump rhodopsins have been characterized using an Escherichia coli expression system because that enables the rapid production of large amounts of recombinant proteins, whereas no success has been reported for eukaryotic rhodopsins. Here, we report a phylogenetically distinct eukaryotic rhodopsin from the dinoflagellate Oxyrrhis marina (O. marina rhodopsin-2, OmR2) that can be expressed in E. coli cells. E. coli cells harboring the OmR2 gene showed an outward proton-pumping activity, indicating its functional expression. Spectroscopic characterization of the purified OmR2 protein revealed several features as follows: (1) an absorption maximum at 533 nm with all-trans retinal chromophore, (2) the possession of the deprotonated counterion (pKa = 3.0) of the protonated Schiff base and (3) a rapid photocycle through several distinct photointermediates. Those features are similar to those of known eukaryotic proton pump rhodopsins. Our successful characterization of OmR2 expressed in E. coli cells could build a basis for understanding and utilizing eukaryotic rhodopsins.

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Characterization of Recombinant Adeno-Associated Viruses (rAAVs) for Gene Therapy Using Orthogonal Techniques

Pharmaceutics ◽

10.3390/pharmaceutics13040586 ◽

2021 ◽

Vol 13 (4) ◽

pp. 586

Author(s):

Liam Cole ◽

Diogo Fernandes ◽

Maryam T. Hussain ◽

Michael Kaszuba ◽

John Stenson ◽

...

Keyword(s):

Gene Therapy ◽

Light Scattering ◽

Dynamic Light Scattering ◽

Viral Vector ◽

Structural Characteristics ◽

Genetic Material ◽

Label Free ◽

Gene Therapies ◽

Multiple Challenges

Viruses are increasingly used as vectors for delivery of genetic material for gene therapy and vaccine applications. Recombinant adeno-associated viruses (rAAVs) are a class of viral vector that is being investigated intensively in the development of gene therapies. To develop efficient rAAV therapies produced through controlled and economical manufacturing processes, multiple challenges need to be addressed starting from viral capsid design through identification of optimal process and formulation conditions to comprehensive quality control. Addressing these challenges requires fit-for-purpose analytics for extensive characterization of rAAV samples including measurements of capsid or particle titer, percentage of full rAAV particles, particle size, aggregate formation, thermal stability, genome release, and capsid charge, all of which may impact critical quality attributes of the final product. Importantly, there is a need for rapid analytical solutions not relying on the use of dedicated reagents and costly reference standards. In this study, we evaluate the capabilities of dynamic light scattering, multiangle dynamic light scattering, and SEC–MALS for analyses of rAAV5 samples in a broad range of viral concentrations (titers) at different levels of genome loading, sample heterogeneity, and sample conditions. The study shows that DLS and MADLS® can be used to determine the size of full and empty rAAV5 (27 ± 0.3 and 33 ± 0.4 nm, respectively). A linear range for rAAV5 size and titer determination with MADLS was established to be 4.4 × 1011–8.7 × 1013 cp/mL for the nominally full rAAV5 samples and 3.4 × 1011–7 × 1013 cp/mL for the nominally empty rAAV5 samples with 3–8% and 10–37% CV for the full and empty rAAV5 samples, respectively. The structural stability and viral load release were also inferred from a combination of DLS, SEC–MALS, and DSC. The structural characteristics of the rAAV5 start to change from 40 °C onward, with increasing aggregation observed. With this study, we explored and demonstrated the applicability and value of orthogonal and complementary label-free technologies for enhanced serotype-independent characterization of key properties and stability profiles of rAAV5 samples.

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