scholarly journals Targeted Gene Integration into Nuclear Genome of Microalgae Using Cre/loxP Recombination System

2021 ◽  
Vol 333 ◽  
pp. 07003
Author(s):  
Kazuki Shirakawa ◽  
Yoshinori Kawabe ◽  
Guan Huang ◽  
Akira Ito ◽  
Masamichi Kamihira
Keyword(s):  
Expression Vector ◽  
Fluorescent Protein ◽  
Heterologous Gene Expression ◽  
Nuclear Genome ◽  
Green Fluorescent Protein Gene ◽  
Donor Vector ◽  
Recombination System ◽  
Gene Integration ◽  
Founder Cells ◽  
Targeted Gene Integration

Genetically modified microalgae have been expected to be a useful tool for bioenergy and recombinant protein production. However, random integration of transgene in the microalgae nuclear genome is susceptible to gene silencing of heterologous gene expression. Here, we attempted to perform targeted gene integration into a pre-determined nuclear genomic site of Chlamydomonas reinhardtii using Cre/loxP recombination system for stable transgene expression. We constructed an expression vector plasmid encoding reporter genes (zeocin resistant gene and green fluorescent protein gene; Zeo-2A-GFP) and mutated loxP to generate founder cells. A donor vector encoding IFNα-4 and paromomycin resistant genes flanked by corresponding mutated loxPs was constructed and introduced into founder cells together with a Cre expression vector. The optimal ratio of donor vector to Cre expression vector was determined by counting the number of paromomycin resistant colonies. For the established clones, the targeted integration was confirmed by genomic PCR using various specific primer sets. Target genes in the donor vector could be integrated into the expected genomic site of C. reinhardtii using Cre/loxP system. RT-PCR revealed that IFNα-4 was expressed in five independent transgenic cell lines tested. This result suggests that Cre-based cell engineering is a promising approach to generate smart microalgae expressing foreign genes.

scholarly journals Influence of the combination of last sense codon and stop codon on expression efficiency of green fluorescent protein gene in Escherichia coli when the expression vector pKK223-3

2018 ◽  
Vol 238 ◽  
pp. 04003
Author(s):  
Xing Zhang ◽  
Aiping Fei ◽  
Yong Wang ◽  
Zhigang Fang ◽  
Yingxue Teng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Expression Vector ◽  
Protein Gene ◽  
Fluorescent Protein ◽  
Stop Codon ◽  
Green Fluorescent Protein Gene ◽  
Expression Efficiency ◽  
Green Fluorescent ◽  
Sense Codon ◽  
Gfp Tag

In this paper, the influence of the combination of last sense codon and stop codon on expression efficiency was studied. By our study, for the last sense codon CCG, the RFI of GFP(CCG) was 2.1 fold when the stop codon was UAA, but in comparison, the RFI was 1.1 fold when the stop codon was changed from UAA to UAG. For last sense codon TAG, the RFI of GFP(TAG) with the stop codon UAG was stronger than that with the stop codons UAA and UGA.

scholarly journals Creation of Golden Gate constructs for gene doctoring

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Nicholas M. Thomson ◽  
Chuanzhen Zhang ◽  
Eleftheria Trampari ◽  
Mark J. Pallen
Keyword(s):  
Free Choice ◽  
Gene Editing ◽  
Fluorescent Protein ◽  
Dna Fragments ◽  
Golden Gate ◽  
Donor Plasmid ◽  
Recombination System ◽  
Green Fluorescent ◽  
Λ Red

Abstract Background Gene doctoring is an efficient recombination-based genetic engineering approach to mutagenesis of the bacterial chromosome that combines the λ-Red recombination system with a suicide donor plasmid that is cleaved in vivo to generate linear DNA fragments suitable for recombination. The use of a suicide donor plasmid makes Gene Doctoring more efficient than other recombineering technologies. However, generation of donor plasmids typically requires multiple cloning and screening steps. Results We constructed a simplified acceptor plasmid, called pDOC-GG, for the assembly of multiple DNA fragments precisely and simultaneously to form a donor plasmid using Golden Gate assembly. Successful constructs can easily be identified through blue-white screening. We demonstrated proof of principle by inserting a gene for green fluorescent protein into the chromosome of Escherichia coli. We also provided related genetic parts to assist in the construction of mutagenesis cassettes with a tetracycline-selectable marker. Conclusions Our plasmid greatly simplifies the construction of Gene Doctoring donor plasmids and allows for the assembly of complex, multi-part insertion or deletion cassettes with a free choice of target sites and selection markers. The tools we developed are applicable to gene editing for a wide variety of purposes in Enterobacteriaceae and potentially in other diverse bacterial families.

Efficient Knockout of Transplanted Green Fluorescent Protein Gene in Medaka Using TALENs

2014 ◽  
Vol 16 (6) ◽  
pp. 674-683 ◽  
Author(s):  
Chao Qiu ◽  
Bin Cheng ◽  
Yunsheng Zhang ◽  
Rong Huang ◽  
Lanjie Liao ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Protein Gene ◽  
Fluorescent Protein ◽  
Green Fluorescent Protein Gene ◽  
Green Fluorescent

scholarly journals Hierarchy among Viral RNA (vRNA) Segments in Their Role in vRNA Incorporation into Influenza A Virions

2006 ◽  
Vol 80 (5) ◽  
pp. 2318-2325 ◽  
Author(s):  
Yukiko Muramoto ◽  
Ayato Takada ◽  
Ken Fujii ◽  
Takeshi Noda ◽  
Kiyoko Iwatsuki-Horimoto ◽  
...  
Keyword(s):  
Influenza A ◽  
Fluorescent Protein ◽  
Virus Assembly ◽  
Viral Rna ◽  
Green Fluorescent Protein Gene ◽  
Influenza A Viruses ◽  
Coding Regions ◽  
Virion Incorporation ◽  
Green Fluorescent ◽  
Efficient Viral Replication

ABSTRACT The genome of influenza A viruses comprises eight negative-strand RNA segments. Although all eight segments must be present in cells for efficient viral replication, the mechanism(s) by which these viral RNA (vRNA) segments are incorporated into virions is not fully understood. We recently found that sequences at both ends of the coding regions of the HA, NA, and NS vRNA segments of A/WSN/33 play important roles in the incorporation of these vRNAs into virions. In order to similarly identify the regions of the PB2, PB1, and PA vRNAs of this strain that are critical for their incorporation, we generated a series of mutant vRNAs that possessed the green fluorescent protein gene flanked by portions of the coding and noncoding regions of the respective segments. For all three polymerase segments, deletions at the ends of their coding regions decreased their virion incorporation efficiencies. More importantly, these regions not only affected the incorporation of the segment in which they reside, but were also important for the incorporation of other segments. This effect was most prominent with the PB2 vRNA. These findings suggest a hierarchy among vRNA segments for virion incorporation and may imply intersegment association of vRNAs during virus assembly.

scholarly journals Pseudomonas syringae Effector avrB Confers Soybean Cultivar-Specific Avirulence on Soybean mosaic virus Adapted for Transgene Expression but Effector avrPto Does Not

2006 ◽  
Vol 19 (3) ◽  
pp. 304-312 ◽  
Author(s):  
Li Wang ◽  
Alan Eggenberger ◽  
John Hill ◽  
Adam J. Bogdanove
Keyword(s):  
Mosaic Virus ◽  
Pseudomonas Syringae ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Soybean Mosaic Virus ◽  
Hypersensitive Reaction ◽  
Green Fluorescent Protein Gene ◽  
Avirulence Genes ◽  
Pathogenesis Related Protein ◽  
Viral Movement

Soybean mosaic virus (SMV) was adapted for transgene expression in soybean and used to examine the function of avirulence genes avrB and avrPto of Pseudomonas syringae pvs. glycinea and tomato, respectively. A cloning site was introduced between the P1 and HC-Pro genes in 35S-driven infectious cDNAs of strains SMV-N and SMV-G7. Insertion of the uidA gene or the green fluorescent protein gene into either modified cDNA and bombardment into primary leaves resulted in systemic expression that reflected the pattern of viral movement into uninoculated leaves. Insertion of avrB blocked symptom development and detectable viral movement in cv. Harosoy, which carries the Rpg1-b resistance gene corresponding to avrB, but not in cvs. Keburi or Hurrelbrink, which lack Rpg1-b. In Keburi and Hurrelbrink, symptoms caused by SMV carrying avrB appeared more quickly and were more severe than those caused by the virus without avrB. Insertion of avrPto enhanced symptoms in Harosoy, Hurrelbrink, and Keburi. This result was unexpected because avrPto was reported to confer avirulence on P. syringae pv. glycinea inoculated to Harosoy. We inoculated Harosoy with P. syringae pv. glycinea expressing avrPto, but observed no hypersensitive reaction, avrPto-dependent induction of pathogenesis-related protein 1a, or limitation of bacterial population growth. In Hurrelbrink, avrPto enhanced bacterial multiplication and exacerbated symptoms. Our results establish SMV as an expression vector for soybean. They demonstrate that resistance triggered by avrB is effective against SMV, and that avrB and avrPto have general virulence effects in soybean. The results also led to a reevaluation of the reported avirulence activity of avrPto in this plant.

scholarly journals Response of immunocompetent and immunosuppressed Spodoptera littoralis larvae to baculovirus infection

2006 ◽  
Vol 87 (8) ◽  
pp. 2217-2225 ◽  
Author(s):  
Hadassah Rivkin ◽  
Jeremy A. Kroemer ◽  
Alexander Bronshtein ◽  
Eduard Belausov ◽  
Bruce A. Webb ◽  
...  
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
Spodoptera Littoralis ◽  
Fluorescent Protein ◽  
Oral Route ◽  
Green Fluorescent Protein Gene ◽  
Successful Infection ◽  
Baculovirus Infection ◽  
Budded Virus ◽  
Green Fluorescent

The Mediterranean lepidopteran pest Spodoptera littoralis is highly resistant to infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) via the oral route, but highly sensitive to infection with budded virus (BV) via the intrahaemocoelic route. To study the fate of AcMNPV infection in S. littoralis, vHSGFP, an AcMNPV recombinant that expresses the reporter green fluorescent protein gene under the control of the Drosophila heat-shock promoter, and high-resolution fluorescence microscopy were utilized. S. littoralis fourth-instar larvae infected orally with vHSGFP showed melanization and encapsulation of virus-infected tracheoblast cells serving the midgut columnar cells. At 72 h post-infection, the viral foci were removed during the moult clearing the infection. Thus, oral infection was restricted by immune responses to the midgut and midgut-associated tracheal cells. By contrast, injection of BV into the haemocoel resulted in successful infection of tracheoblasts, followed by spread of the virus through the tracheal epidermis to other tissues. However, in contrast to fully permissive infections where tracheoblasts and haemocytes are equally susceptible to infection, a severe limitation to vHSGFP infection of haemocytes was observed. To investigate the resistance of S. littoralis haemocytes to BV infection with AcMNPV, the larval immune system was suppressed with the Chelonus inanitus polydnavirus or a putatively immunosuppressive polydnavirus gene, P-vank-1. Both treatments increased the susceptibility of S. littoralis larvae to AcMNPV. It is concluded that the resistance of S. littoralis to AcMNPV infection involves both humoral and cellular immune responses that act at the gut and haemocyte levels. The results also support the hypothesis that tracheolar cells mediate establishment of systemic baculovirus infections in lepidopteran larvae. The finding that polydnaviruses and their encoded genes synergize baculovirus infection also provides an approach to dissecting the responses of the lepidopteran immune system to viruses by using specific polydnavirus immunosuppressive genes.

Laser-induced gene expression in specific cells of transgenic zebrafish

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1953-1960 ◽  
Author(s):  
M.C. Halloran ◽  
M. Sato-Maeda ◽  
J.T. Warren ◽  
F. Su ◽  
Z. Lele ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Green Fluorescent Protein Gene ◽  
Transgenic Zebrafish ◽  
Hsp70 Promoter ◽  
Expression Of Genes ◽  
Transgenic Lines ◽  
Transgenic Embryos ◽  
Green Fluorescent

Over the past few years, a number of studies have described the generation of transgenic lines of zebrafish in which expression of reporters was driven by a variety of promoters. These lines opened up the real possibility that transgenics could be used to complement the genetic analysis of zebrafish development. Transgenic lines in which the expression of genes can be regulated both in space and time would be especially useful. Therefore, we have cloned the zebrafish promoter for the inducible hsp70 gene and made stable transgenic lines of zebrafish that express the reporter green fluorescent protein gene under the control of a hsp70 promoter. At normal temperatures, green fluorescent protein is not detectable in transgenic embryos with the exception of the lens, but is robustly expressed throughout the embryo following an increase in ambient temperature. Furthermore, we have taken advantage of the accessibility and optical clarity of the embryos to express green fluorescent protein in individual cells by focussing a sublethal laser microbeam onto them. The targeted cells appear to develop normally: cells migrate normally, neurons project axons that follow normal pathways, and progenitor cells divide and give rise to normal progeny cells. By generating other transgenic lines in which the hsp70 promoter regulates genes of interest, it should be possible to examine the in vivo activity of the gene products by laser-inducing specific cells to express them in zebrafish embryos. As a first test, we laser-induced single muscle cells to make zebrafish Sema3A1, a semaphorin that is repulsive for specific growth cones, in a hsp70-sema3A1 transgenic line of zebrafish and found that extension by the motor axons was retarded by the induced muscle.

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