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Schuller A, Cserjan-Puschmann M, Tauer C, Jarmer J, Wagenknecht M, Reinisch D, Grabherr R, Striedner G. Escherichia coli σ 70 promoters allow expression rate control at the cellular level in genome-integrated expression systems. Microb Cell Fact 2020; 19:58. [PMID: 32138729 PMCID: PMC7059391 DOI: 10.1186/s12934-020-01311-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/17/2020] [Indexed: 12/18/2022] Open
Abstract
Background The genome-integrated T7 expression system offers significant advantages, in terms of productivity and product quality, even when expressing the gene of interest (GOI) from a single copy. Compared to plasmid-based expression systems, this system does not incur a plasmid-mediated metabolic load, and it does not vary the dosage of the GOI during the production process. However, long-term production with T7 expression system leads to a rapidly growing non-producing population, because the T7 RNA polymerase (RNAP) is prone to mutations. The present study aimed to investigate whether two σ70 promoters, which were recognized by the Escherichia coli host RNAP, might be suitable in genome-integrated expression systems. We applied a promoter engineering strategy that allowed control of expressing the model protein, GFP, by introducing lac operators (lacO) into the constitutive T5 and A1 promoter sequences. Results We showed that, in genome-integrated E. coli expression systems that used σ70 promoters, the number of lacO sites must be well balanced. Promoters containing three and two lacO sites exhibited low basal expression, but resulted in a complete stop in recombinant protein production in partially induced cultures. In contrast, expression systems regulated by a single lacO site and the lac repressor element, lacIQ, on the same chromosome caused very low basal expression, were highly efficient in recombinant protein production, and enables fine-tuning of gene expression levels on a cellular level. Conclusions Based on our results, we hypothesized that this phenomenon was associated with the autoregulation of the lac repressor protein, LacI. We reasoned that the affinity of LacI for the lacO sites of the GOI must be lower than the affinity of LacI to the lacO sites of the endogenous lac operon; otherwise, LacI autoregulation could not take place, and the lack of LacI autoregulation would lead to a disturbance in lac repressor-mediated regulation of transcription. By exploiting the mechanism of LacI autoregulation, we created a novel E. coli expression system for use in recombinant protein production, synthetic biology, and metabolic engineering applications.
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Affiliation(s)
- Artur Schuller
- Christian Doppler Laboratory for Production of Next-level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.
| | - Christopher Tauer
- Christian Doppler Laboratory for Production of Next-level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Johanna Jarmer
- Boehringer Ingelheim RCV GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, 1120, Vienna, Austria
| | - Martin Wagenknecht
- Boehringer Ingelheim RCV GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, 1120, Vienna, Austria
| | - Daniela Reinisch
- Boehringer Ingelheim RCV GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, 1120, Vienna, Austria
| | - Reingard Grabherr
- Christian Doppler Laboratory for Production of Next-level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
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Gone S, Alfonso-Prieto M, Paudyal S, Nicholson AW. Mechanism of Ribonuclease III Catalytic Regulation by Serine Phosphorylation. Sci Rep 2016; 6:25448. [PMID: 27150669 PMCID: PMC4858673 DOI: 10.1038/srep25448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/15/2016] [Indexed: 12/15/2022] Open
Abstract
Ribonuclease III (RNase III) is a conserved, gene-regulatory bacterial endonuclease that cleaves double-helical structures in diverse coding and noncoding RNAs. RNase III is subject to multiple levels of control, reflective of its global regulatory functions. Escherichia coli (Ec) RNase III catalytic activity is known to increase during bacteriophage T7 infection, reflecting the expression of the phage-encoded protein kinase, T7PK. However, the mechanism of catalytic enhancement is unknown. This study shows that Ec-RNase III is phosphorylated on serine in vitro by purified T7PK, and identifies the targets as Ser33 and Ser34 in the N-terminal catalytic domain. Kinetic experiments reveal a 5-fold increase in kcat and a 1.4-fold decrease in Km following phosphorylation, providing a 7.4–fold increase in catalytic efficiency. Phosphorylation does not change the rate of substrate cleavage under single-turnover conditions, indicating that phosphorylation enhances product release, which also is the rate-limiting step in the steady-state. Molecular dynamics simulations provide a mechanism for facilitated product release, in which the Ser33 phosphomonoester forms a salt bridge with the Arg95 guanidinium group, thereby weakening RNase III engagement of product. The simulations also show why glutamic acid substitution at either serine does not confer enhancement, thus underscoring the specific requirement for a phosphomonoester.
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Affiliation(s)
- Swapna Gone
- Department of Chemistry, Philadelphia PA, 19122, USA
| | | | - Samridhdi Paudyal
- Department of Biology, Temple University, Philadelphia PA, 19122, USA
| | - Allen W Nicholson
- Department of Chemistry, Philadelphia PA, 19122, USA.,Department of Biology, Temple University, Philadelphia PA, 19122, USA
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Switt AIM, Sulakvelidze A, Wiedmann M, Kropinski AM, Wishart DS, Poppe C, Liang Y. Salmonella phages and prophages: genomics, taxonomy, and applied aspects. Methods Mol Biol 2015; 1225:237-87. [PMID: 25253259 DOI: 10.1007/978-1-4939-1625-2_15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Since this book was originally published in 2007 there has been a significant increase in the number of Salmonella bacteriophages, particularly lytic virus, and Salmonella strains which have been fully sequenced. In addition, new insights into phage taxonomy have resulted in new phage genera, some of which have been recognized by the International Committee of Taxonomy of Viruses (ICTV). The properties of each of these genera are discussed, along with the role of phage as agents of genetic exchange, as therapeutic agents, and their involvement in phage typing.
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Affiliation(s)
- Andrea I Moreno Switt
- Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Escuela de Medicina Veterinaria, Republica 440, 8370251, Santiago, Chile
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Leon-Velarde CG, Kropinski AM, Chen S, Abbasifar A, Griffiths MW, Odumeru JA. Complete genome sequence of bacteriophage vB_YenP_AP5 which infects Yersinia enterocolitica of serotype O:3. Virol J 2014; 11:188. [PMID: 25347934 PMCID: PMC4283147 DOI: 10.1186/1743-422x-11-188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/19/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Bacteriophage vB_YenP_AP5 is a lytic bacteriophage capable of infecting Yersinia enterocolitica strains of serotype O:3, an epidemiologically significant serotype within this bacterial species that causes yersiniosis in humans. This work describes the complete genome sequence of this phage. RESULTS The genome consists of linear double-stranded DNA of 38,646 bp, with direct terminal repeats of 235 bp in length, and a GC content of 50.7%. There are 45 open reading frames which occupy 89.9% of the genome. Most of the proteins encoded by this virus exhibit sequence similarity to Yersinia phage φYeO3-12 and Salmonella phage φSG-JL2 proteins. CONCLUSIONS Genomic and morphological analyses place the bacteriophage vB_YenP_AP5 in the T7likevirus genus of the subfamily Autographivirinae within the family Podoviridae.
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Affiliation(s)
- Carlos G Leon-Velarde
- />Laboratory Services Division, University of Guelph, Guelph, ON N1H 8J7 Canada
- />Department of Food Science, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Andrew M Kropinski
- />Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1 Canada
- />Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Shu Chen
- />Laboratory Services Division, University of Guelph, Guelph, ON N1H 8J7 Canada
| | - Arash Abbasifar
- />Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Mansel W Griffiths
- />Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON N1G 2W1 Canada
- />Department of Food Science, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Joseph A Odumeru
- />Department of Food Science, University of Guelph, Guelph, ON N1G 2W1 Canada
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Comparative transcription profiling and in-depth characterization of plasmid-based and plasmid-free Escherichia coli expression systems under production conditions. Appl Environ Microbiol 2013; 79:3802-12. [PMID: 23584782 DOI: 10.1128/aem.00365-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmid-based Escherichia coli BL21(DE3) expression systems are extensively used for the production of recombinant proteins. However, the combination of a high gene dosage with strong promoters exerts extremely stressful conditions on producing cells, resulting in a multitude of protective reactions and malfunctions in the host cell with a strong impact on yield and quality of the product. Here, we provide in-depth characterization of plasmid-based perturbations in recombinant protein production. A plasmid-free T7 system with a single copy of the gene of interest (GOI) integrated into the genome was used as a reference. Transcriptomics in combination with a variety of process analytics were used to characterize and compare a plasmid-free T7-based expression system to a conventional pET-plasmid-based expression system, with both expressing human superoxide dismutase in fed-batch cultivations. The plasmid-free system showed a moderate stress response on the transcriptional level, with only minor effects on cell growth. In contrast to this finding, comprehensive changes on the transcriptome level were observed in the plasmid-based expression system and cell growth was heavily impaired by recombinant gene expression. Additionally, we found that the T7 terminator is not a sufficient termination signal. Overall, this work reveals that the major metabolic burden in plasmid-based systems is caused at the level of transcription as a result of overtranscription of the multicopy product gene and transcriptional read-through of T7 RNA polymerase. We therefore conclude that the presence of high levels of extrinsic mRNAs, competing for the limited number of ribosomes, leads to the significantly reduced translation of intrinsic mRNAs.
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Gone S, Nicholson AW. Bacteriophage T7 protein kinase: Site of inhibitory autophosphorylation, and use of dephosphorylated enzyme for efficient modification of protein in vitro. Protein Expr Purif 2012; 85:218-23. [PMID: 22951189 DOI: 10.1016/j.pep.2012.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/12/2012] [Accepted: 08/13/2012] [Indexed: 12/01/2022]
Abstract
Bacteriophage T7 encodes a serine/threonine-specific protein kinase that phosphorylates multiple cellular proteins during infection of Escherichia coli. Recombinant T7 protein kinase (T7PK), normally purified in phosphorylated form, exhibits a modest level of phosphotransferase activity. A procedure is described that provides dephosphorylated T7PK with an enhanced ability to phosphorylate protein substrates, including translation initiation factor IF1 and the nuclease domain of ribonuclease III. Mass spectrometric analysis identified Thr12 as the site of IF1 phosphorylation in vitro. T7PK undergoes Mg(2+)-dependent autophosphorylation on Ser216 in vitro, which also is modified in vivo. The inability to isolate the presumptive autophosphorylation-resistant T7PK Ser216Ala mutant indicates a toxicity of the phosphotransferase activity and suggests a role for Ser216 modification in limiting T7PK activity during infection.
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Affiliation(s)
- Swapna Gone
- Department of Chemistry, Temple University, 1901 North 13th St., Philadelphia, PA 19122, USA
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The genome and proteome of the Kluyvera bacteriophage Kvp1--another member of the T7-like Autographivirinae. Virol J 2008; 5:122. [PMID: 18937848 PMCID: PMC2579914 DOI: 10.1186/1743-422x-5-122] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 10/20/2008] [Indexed: 11/23/2022] Open
Abstract
Background Kluyvera, a genus within the family Enterobacteriaceae, is an infrequent cause of human infections. Bacteriophage Kvp1, the only bacteriophage isolated for one of its species, Kluyvera cryocrescens, is a member of the viral family Podoviridae. Results The genome of Kvp1, the first Kluyvera cryocrescens-specific bacteriophage, was sequenced using pyrosequencing (454 technology) at the McGill University and Genome Québec Innovation Centre. The two contigs were closed using PCR and the sequence of the terminal repeats completed by primer walking off the phage DNA. The phage structural proteome was investigated by SDS-PAGE and mass spectrometry. Conclusion At 39,472 bp, the annotated genome revealed a closer relationship to coliphage T3 than T7 with Kvp1 containing homologs to T3 early proteins S-adenosyl-L-methionine hydrolase (0.3) and protein kinase (0.7). The quantitative nature of the relationships between Kvp1 and the other members of the T7-like virus genus (T7, T3, φA1122, φYeO3-12, Berlin, K1F, VP4 and gh-1) was confirmed using CoreGenes.
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Majtan T, Halgasova N, Bukovska G, Timko J. Transcriptional profiling of bacteriophage BFK20: Coexpression interrogated by “guilt-by-association” algorithm. Virology 2007; 359:55-65. [PMID: 17052739 DOI: 10.1016/j.virol.2006.09.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/04/2006] [Accepted: 09/19/2006] [Indexed: 10/24/2022]
Abstract
Global gene expression profiling of bacteriophage BFK20 infecting the industrial L-lysine producer Brevibacterium flavum CCM 251 was performed using DNA microarray. The relative gene expressions were measured in fourteen time samples collected during phage development. Phage genes were classified as early, middle, late or unassigned based on complex expression patterns during infection. Temporal classification of BFK20 genes was in concordance with previous predictions. However, proposed late regulatory genes were reclassified and new functional assignments for ORF55 were strongly suggested. Furthermore, we consider possible functions of other genes and their products regarding coexpression pattern by using "guilt-by-association" algorithm. Microarray results were validated using real-time RT-PCR. The detailed description of phage BFK20 transcriptional profile can answer the basic questions of its life cycle and it also can help to prevent phage contamination during industrial fermentation. In addition, this work presents the first complete microarray time course study of gene expression utilizing loop design.
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Affiliation(s)
- Tomas Majtan
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovakia.
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9
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Kropinski AM, Sulakvelidze A, Konczy P, Poppe C. Salmonella phages and prophages--genomics and practical aspects. Methods Mol Biol 2007; 394:133-75. [PMID: 18363236 DOI: 10.1007/978-1-59745-512-1_9] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Numerous bacteriophages specific to Salmonella have been isolated or identified as part of host genome sequencing projects. Phylogenetic analysis of the sequenced phages, based on related protein content using CoreGenes, reveals that these viruses fall into five groupings (P27-like, P2-like, lambdoid, P22-like, and T7-like) and three outliers (epsilon15, KS7, and Felix O1). The P27 group is only represented by ST64B; the P2 group contains Fels-2, SopEphi, and PSP3; the lambdoid Salmonella phages include Gifsy-1, Gifsy-2, and Fels-1. The P22-like viruses include epsilon34, ES18, P22, ST104, and ST64T. The only member of the T7-like group is SP6. The properties of each of these phages are discussed, along with their role as agents of genetic exchange and as therapeutic agents and their involvement in phage typing.
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Affiliation(s)
- Andrew M Kropinski
- Host and Pathogen Determinants, Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario
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Chatterjee DK, Esposito D. Enhanced soluble protein expression using two new fusion tags. Protein Expr Purif 2005; 46:122-9. [PMID: 16146696 DOI: 10.1016/j.pep.2005.07.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 07/27/2005] [Accepted: 07/28/2005] [Indexed: 11/18/2022]
Abstract
Production of soluble recombinant proteins is vital for structure-function analysis and therapeutic applications. Unfortunately, when expressed in a heterologous host, such as Escherichia coli, most proteins are expressed as insoluble aggregates. Two new fusion partners have been identified to address these solubility problems. One of the tags was derived from a bacteriophage T7 protein kinase and the other one from a small E. coli chaperone, Skp. We have expressed a panel of insoluble human proteins including Hif1alpha, IL13, and folliculin as fusion proteins using these tags. Most of these fusion proteins were able to be expressed in a soluble form and could be purified by virtue of a Strep-tag II installed at the amino-terminal end of the fusion partners. In addition, we show that some of these proteins remained soluble after removal of the fusion tags by a site-specific protease. The results with these tags compare favorably to results with the most commonly used solubility tags described in the literature. Therefore, these two new fusion tags have the potential to express soluble proteins when fused with many recalcitrant proteins.
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Affiliation(s)
- Deb K Chatterjee
- Protein Expression Laboratory, SAIC-Frederick, Inc., National Cancer Institute at Frederick, 1050 Boyles Street, Building 327 Frederick, MD 21702, USA.
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Marchand I, Nicholson AW, Dreyfus M. Bacteriophage T7 protein kinase phosphorylates RNase E and stabilizes mRNAs synthesized by T7 RNA polymerase. Mol Microbiol 2001; 42:767-76. [PMID: 11722741 DOI: 10.1046/j.1365-2958.2001.02668.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The T7 protein encoded by the early gene 0.7 exhibits bifunctional activity. Whereas its C-terminal one-third participates in host transcription shut-off, the N-terminal two-thirds bears a protein kinase ('PK') activity that can phosphorylate a number of host proteins in addition to itself. Here, we show that, when PK is expressed in uninfected Escherichia coli cells, the C-terminal half of RNase E and the associated RNA helicase RhlB are heavily phosphorylated. Meanwhile, a subset of RNase E substrates, including the lac and cat mRNAs synthesized by bacteriophage T7 RNA polymerase (RNAP), are stabilized. These mRNAs are genuinely less stable than their counterparts synthesized by E. coli RNAP, because T7 RNAP outpaces translating ribosomes, creating naked, RNase E-sensitive mRNA stretches behind itself. Thus, PK alleviates this effect of desynchronizing transcription and translation. The relationship between the modification of RNase E and RhlB and these mRNA stabilization effects, which may be relevant to the stability of late T7 mRNAs during infection, is discussed.
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Affiliation(s)
- I Marchand
- Laboratoire de Génétique Moléculaire (CNRS UMR 8541), ENS, 46 rue d'Ulm, 75230 Paris, France
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