scholarly journals Modified E. coli strains enhance baculovirus production by elimination of aberrant transposition events

2021 ◽  
Author(s):  
Carissa Grose ◽  
Chelsea Wright ◽  
Jennifer Mehalko ◽  
Dominic Esposito
Keyword(s):  
Recombinant Protein ◽  
False Positive ◽  
Insect Cells ◽  
Expression System ◽  
Recombinant Baculovirus ◽  
Attachment Site ◽  
Improve Quality ◽  
Post Translational Modifications ◽  
E Coli ◽  
Tn7 Transposition

AbstractBaculovirus technology has been the most commonly used expression system for insect cells both due to its potential to generate a large amount of recombinant protein as well as the benefit of post-translational modifications. The most commonly used system to generate recombinant baculoviruses is the Tn7 transposition-based technology known as Bac-to-Bac. Although improvements have been made to this system to further improve quality and reproducibility of baculovirus production, recent data suggests that improved strains still have potential issues with contamination of non-recombinant baculovirus caused by improper transposition into a Tn7 site in the E. coli chromosome. Here we describe a new option for alteration of the E. coli genome to completely block the native Tn7 attachment site, leading to far fewer false positive bacmid colonies being selected and eliminating all risk of non-recombinant baculovirus production.

scholarly journals Recombinant protein production provoked accumulation of ATP, fructose-1,6-bisphosphate and pyruvate in E. coli K12 strain TG1

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jan Weber ◽  
Zhaopeng Li ◽  
Ursula Rinas
Keyword(s):  
Recombinant Protein ◽  
Recombinant Protein Production ◽  
Protein Production ◽  
Expression System ◽  
Limiting Factors ◽  
Expression Vectors ◽  
Metabolic Enzyme ◽  
E Coli ◽  
Metabolic Burden ◽  
Fructose 1,6 Bisphosphate

Abstract Background Recently it was shown that production of recombinant proteins in E. coli BL21(DE3) using pET based expression vectors leads to metabolic stress comparable to a carbon overfeeding response. Opposite to original expectations generation of energy as well as catabolic provision of precursor metabolites were excluded as limiting factors for growth and protein production. On the contrary, accumulation of ATP and precursor metabolites revealed their ample formation but insufficient withdrawal as a result of protein production mediated constraints in anabolic pathways. Thus, not limitation but excess of energy and precursor metabolites were identified as being connected to the protein production associated metabolic burden. Results Here we show that the protein production associated accumulation of energy and catabolic precursor metabolites is not unique to E. coli BL21(DE3) but also occurs in E. coli K12. Most notably, it was demonstrated that the IPTG-induced production of hFGF-2 using a tac-promoter based expression vector in the E. coli K12 strain TG1 was leading to persistent accumulation of key regulatory molecules such as ATP, fructose-1,6-bisphosphate and pyruvate. Conclusions Excessive energy generation, respectively, accumulation of ATP during recombinant protein production is not unique to the BL21(DE3)/T7 promoter based expression system but also observed in the E. coli K12 strain TG1 using another promoter/vector combination. These findings confirm that energy is not a limiting factor for recombinant protein production. Moreover, the data also show that an accelerated glycolytic pathway flux aggravates the protein production associated “metabolic burden”. Under conditions of compromised anabolic capacities cells are not able to reorganize their metabolic enzyme repertoire as required for reduced carbon processing.

scholarly journals A Newly Designed EGFP-2A Peptide Monocistronic Baculoviral Vector for Concatenating the Expression of Recombinant Proteins in Insect Cells

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 291 ◽  
Author(s):  
Chih-Yu Wu ◽  
Chao-Wei Huang ◽  
Yu-Shin Nai ◽  
Pei-Yu Chu ◽  
Chung-Hsiung Wang ◽  
...  
Keyword(s):  
Recombinant Proteins ◽  
Posttranslational Modifications ◽  
Mammalian Cells ◽  
Insect Cells ◽  
Fluorescent Protein ◽  
Expression System ◽  
Recombinant Baculovirus ◽  
New Combination ◽  
Vector System ◽  
Baculovirus Expression Vector

Recombinant proteins produced by the baculovirus expression vector system (BVES) have been widely applied in the agricultural and medical fields. However, the procedure for protein expression is inefficient and needs to be improved. Herein, we propose a simple construct that incorporates a selectable marker (enhanced green fluorescent protein, EGFP) and a picorna viral-derived “self-cleaving” 2A-like peptide to separate the EGFP and target proteins in a monocistronic baculovirus vector to facilitate isolation of the recombinant baculovirus in the BVES. In this study, porcine adiponectin (ADN), a secreted, multimeric protein with insulin-sensitizing properties, was used to demonstrate its utility in our EGFP-2A-based expression system. EGFP and ADN were simultaneously expressed by a recombinant alphabaculovirus. Co-expression of EGFP facilitates the manipulation of the following processes, such as determining expression kinetics and harvesting ADN. The results showed that the 2A “self-cleaving” process does not interfere with EGFP activity or with signal peptide removal and the secretion of recombinant ADN. Posttranslational modifications, including glycosylation, of the recombinant ADN occurred in insect cells, and the formation of various multimers was further verified. Most importantly, the insect-produced ADN showed a similar bioactivity to that of mammalian cells. This concept provides a practical and economic approach that utilizes a new combination of alphabaculovirus/insect cell expression systems for future applications.

Effect of supplementing Moringa oleifera essential oils on milk quality and fatty acid profile in dairy sheep

2019 ◽  
Author(s):  
N. Hemamalini ◽  
S. Ezhilmathi ◽  
A. Angela Mercy
Keyword(s):  
Recombinant Protein ◽  
Protein Expression ◽  
Cell Biology ◽  
Genetic Manipulation ◽  
Recombinant Protein Expression ◽  
Coli Strain ◽  
Expression Vectors ◽  
Functional Domain ◽  
Post Translational Modifications ◽  
E Coli

Escherichia coli is the most extensively used organism in recombinant protein production. It has several advantages including a very short life cycle, ease of genetic manipulation and the well-known cell biology etc. which makes E. coli as the perfect host for recombinant protein expression. Despite many advantages, E. coli also have few disadvantages such as coupled transcription and translation and lack of eukaryotic post-translational modifications. These challenges can be overcome by adopting several strategies such as, using different E. coli expression vectors, changing the gene sequence without altering the functional domain, modified E. coli strain usage, changing the culture parameters and co-expression with a molecular chaperone. In this review, we present the level of strategies used to enhance the recombinant protein expression and its stability in E. coli.

scholarly journals Biosynthesis of recombinant human pro-α1(III) chains in a baculovirus expression system: production of disulphide-bonded and non-disulphide-bonded species containing full-length triple helices

1995 ◽  
Vol 312 (3) ◽  
pp. 847-853 ◽  
Author(s):  
M Tomita ◽  
N Ohkura ◽  
M Ito ◽  
T Kato ◽  
P M Royce ◽  
...  
Keyword(s):  
Insect Cells ◽  
Incubation Temperature ◽  
Expression System ◽  
Significant Proportion ◽  
Recombinant Baculovirus ◽  
Baculovirus Expression System ◽  
Dermal Fibroblasts ◽  
Full Length ◽  
Type Iii Collagen ◽  
Procollagen Iii

We have investigated the expression of human procollagen III by insect cells infected with a recombinant baculovirus carrying cDNA for the pro-alpha1(III) chain of type-III collagen. A high level of expression was obtained, and a small proportion of the heterologously expressed pro-alpha1(III) chains formed normally disulphide-bonded procollagen III, which was secreted into the culture medium. This species displayed a melting temperature (Tm) of approx. 38 degrees C as assessed by its resistance to digestion by a mixture of trypsin and chymotrypsin, slightly lower than that of 39.5 degrees C for procollagen III synthesized by cultured human dermal fibroblasts, and reflected a slight degree of under-hydroxylation of prolyl residues. This is possibly a consequence of the lower incubation temperature of insect cells, or of an insufficiency of prolyl hydroxylase activity within them. A significant proportion of the expressed chains formed trimeric molecules of similar thermal stability containing an apparently full-length triple-helical region, but were not disulphide-bonded and not secreted. In addition to providing a source of recombinant human procollagen III, the system promises to be useful in the study of procollagen chain association and subsequent folding.

scholarly journals Avian polyomavirus agnoprotein 1a is incorporated into the virus particle as a fourth structural protein, VP4

2001 ◽  
Vol 82 (4) ◽  
pp. 909-918 ◽  
Author(s):  
Reimar Johne ◽  
Hermann Müller
Keyword(s):  
Leucine Zipper ◽  
Insect Cells ◽  
Recombinant Baculovirus ◽  
Structural Protein ◽  
E Coli ◽  
Small Proteins ◽  
Double Stranded Dna ◽  
Infected Insect ◽  
Infected Cells ◽  
Avian Polyomavirus

Agnoproteins, encoded by the 5′-region of the late bicistronic mRNA of some polyomaviruses, are small proteins with largely unknown functions. In avian polyomavirus (APV)-infected cells, mRNAs of seven putative agnoproteins have been observed. Recently, it has been shown that agnoprotein 1a and its truncated variant agnoprotein 1b, encoded by the predominant mRNA species, are essential for APV replication. Here, the presence of agnoprotein 1a is demonstrated in the nucleus of APV-infected cells and in purified APV particles. Interaction between agnoprotein 1a and the major structural protein, VP1, was demonstrated by co-immunoprecipitation experiments using lysates of recombinant baculovirus-infected insect cells. With proteins expressed in E. coli, binding to double-stranded DNA in a sequence-unspecific manner was shown for agnoprotein 1a, whereas agnoprotein 1b failed to bind. A leucine zipper-like motif present in agnoprotein 1a is considered to be involved in DNA binding. Due to the absence of any structural or functional homologies between APV agnoprotein 1a and the agnoproteins of mammalian polyomaviruses, it is suggested that this protein should be renamed VP4, indicating its function as a fourth structural protein of APV.

scholarly journals Regulating the T7 RNA polymerase expression in E. coli BL21 (DE3) to provide more host options for recombinant protein production

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Fei Du ◽  
Yun-Qi Liu ◽  
Ying-Shuang Xu ◽  
Zi-Jia Li ◽  
Yu-Zhou Wang ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Rna Polymerase ◽  
Recombinant Proteins ◽  
Expression System ◽  
T7 Rna Polymerase ◽  
Expression Level ◽  
Foreign Protein ◽  
Atpase Subunit ◽  
E Coli ◽  
Prokaryotic Expression System

AbstractEscherichia coli is the most widely used bacterium in prokaryotic expression system for the production of recombinant proteins. In BL21 (DE3), the gene encoding the T7 RNA polymerase (T7 RNAP) is under control of the strong lacUV5 promoter (PlacUV5), which is leakier and more active than wild-type lac promoter (PlacWT) under certain growth conditions. These characteristics are not advantageous for the production of those recombinant proteins with toxic or growth-burdened. On the one hand, leakage expression of T7 RNAP leads to rapid production of target proteins under non-inducing period, which sucks resources away from cellular growth. Moreover, in non-inducing or inducing period, high expression of T7 RNAP production leads to the high-production of hard-to-express proteins, which may all lead to loss of the expression plasmid or the occurrence of mutations in the expressed gene. Therefore, more BL21 (DE3)-derived variant strains with rigorous expression and different expression level of T7 RNAP should be developed. Hence, we replaced PlacUV5 with other inducible promoters respectively, including arabinose promoter (ParaBAD), rhamnose promoter (PrhaBAD), tetracycline promoter (Ptet), in order to optimize the production of recombinant protein by regulating the transcription level and the leakage level of T7 RNAP. Compared with BL21 (DE3), the constructed engineered strains had higher sensitivity to inducers, among which rhamnose and tetracycline promoters had the lowest leakage ability. In the production of glucose dehydrogenase (GDH), a protein that causes host autolysis, the engineered strain BL21 (DE3::ara) exhibited higher biomass, cell survival rate and foreign protein expression level than that of BL21 (DE3). In addition, these engineered strains had been successfully applied to improve the production of membrane proteins, including E. coli cytosine transporter protein (CodB), the E. coli membrane protein insertase/foldase (YidC), and the E. coli F-ATPase subunit b (Ecb). The engineered strains constructed in this paper provided more host choices for the production of recombinant proteins.

scholarly journals Baculovirus expression and biochemical characterization of the human microsomal triglyceride transfer protein

1999 ◽  
Vol 338 (2) ◽  
pp. 305-310 ◽  
Author(s):  
Penelope J. RITCHIE ◽  
Anne DECOUT ◽  
Joanna AMEY ◽  
Christopher J. MANN ◽  
Jacqueline READ ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Insect Cells ◽  
Expression System ◽  
Microsomal Triglyceride Transfer Protein ◽  
Low Density Lipoproteins ◽  
Attenuated Total Reflection ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Transfer Protein ◽  
Baculovirus Expression

The microsomal triglyceride transfer protein (MTP) complexed to protein disulphide isomerase (PDI) is obligatory for the assembly of chylomicrons and very-low-density lipoproteins. The determination of the atomic structure of the MTP–PDI heterodimer has important implications for the treatment of those forms of hyperlipidaemia associated with the overproduction of very-low-density lipoproteins, which predispose to premature coronary heart disease. To perform structural studies of the human MTP–PDI complex it was necessary to produce milligram quantities of pure protein. We chose the baculovirus expression system for this purpose. Insects cells were co-infected with recombinant viruses encoding FLAG-tagged MTP and His-tagged PDI; the resulting heterodimer was purified by affinity chromatography. From 5 litres of insect cells, 4–6 mg of more than 95% pure recombinant protein was obtained. CD and attenuated total reflection Fourier-transform infrared spectroscopy indicate that the purified protein has around 34% α-helical and 33% β-structure content. The recombinant protein had a comparable triglyceride transfer activity to that of bovine MTP–PDI. The production of polyclonal antibodies raised against the MTP and PDI subunits of the purified protein is described. The present study demonstrates the feasibility of expressing two proteins at high levels in insect cells and describes a transferable methodology for the purification of the resulting protein complex.

scholarly journals Accurate processing and secretion in the baculovirus expression system of an erythroid-cell-stimulating factor consisting of a chimaera of insulin-like growth factor II and an insect insulin-like peptide

1994 ◽  
Vol 299 (1) ◽  
pp. 101-107 ◽  
Author(s):  
L F Congote ◽  
Q Li
Keyword(s):  
Amino Acids ◽  
Growth Factor ◽  
Insect Cells ◽  
Expression System ◽  
Recombinant Baculovirus ◽  
Erythroid Cell ◽  
Insulin Like Growth Factor ◽  
Terminal Sequence ◽  
Factor Ii ◽  
Terminal Amino

A synthetic gene encoding the signal peptide and the N-terminal sequence of bombyxin, an insect insulin-like peptide, and the 58 amino acids of the C-terminal sequence of human insulin-like growth factor II (IGF II) has been expressed using the baculovirus system. This synthetic chimaera was obtained by amplification of four overlapping oligonucleotides using Taq polymerase and cloning into the transfer vector pBluebac. The construct was integrated by homologous recombination into the Autographa californica nuclear polyhedrosis genome. Spodoptera frugiperda Sf9 insect cells infected with the recombinant baculovirus secreted an accurately processed peptide consisting of the ten N-terminal amino acids of bombyxin and the 58 C-terminal amino acids of IGF II. The N-terminal glutamine of bombyxin was changed to asparagine to facilitate sequencing of the synthetic peptide. The chimaera was five times more potent than human recombinant IGF II in its capacity to stimulate thymidine incorporation into erythroid cells of fetal bovine liver in a serum-free medium. It stimulated erythroid colony formation in the presence of 2 microunits/ml erythropoietin in cells cultured over a monolayer of stromal cells of fetal liver. Artificial chimaeras as described here may prove useful for the production of insulin, IGF I and other peptides as secreted proteins in insect cells.

Sign in / Sign up

Export Citation Format

Share Document