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Khandia R, Gurjar P, Romashchenko V, Al-Hussain SA, Alexiou A, Zouganelis G, Zaki MEA. In-silico Codon Context and Synonymous Usage Analysis of Genes for Molecular Mechanisms Inducing Autophagy and Apoptosis with Reference to Neurodegenerative Disorders. J Alzheimers Dis 2024; 99:927-939. [PMID: 38728191 DOI: 10.3233/jad-240158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Background Autophagy and apoptosis are cellular processes that maintain cellular homeostasis and remove damaged or aged organelles or aggregated and misfolded proteins. Stress factors initiate the signaling pathways common to autophagy and apoptosis. An imbalance in the autophagy and apoptosis, led by cascade of molecular mechanism prior to both processes culminate into neurodegeneration. Objective In present study, we urge to investigate the codon usage pattern of genes which are common before initiating autophagy and apoptosis. Methods In the present study, we took up eleven genes (DAPK1, BECN1, PIK3C3 (VPS34), BCL2, MAPK8, BNIP3 L (NIX), PMAIP1, BAD, BID, BBC3, MCL1) that are part of molecular signaling mechanism prior to autophagy and apoptosis. We analyzed dinucleotide odds ratio, codon bias, usage, context, and rare codon analysis. Results CpC and GpG dinucleotides were abundant, with the dominance of G/C ending codons as preferred codons. Clustering analysis revealed that MAPK8 had a distinct codon usage pattern compared to other envisaged genes. Both positive and negative contexts were observed, and GAG-GAG followed by CTG-GCC was the most abundant codon pair. Of the six synonymous arginine codons, two codons CGT and CGA were the rarest. Conclusions The information presented in the study may be used to manipulate the process of autophagy and apoptosis and to check the pathophysiology associated with their dysregulation.
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Affiliation(s)
- Rekha Khandia
- Department of Biochemistry and Genetics, Barkatullah University, Bhopal, India
| | - Pankaj Gurjar
- Centre for Global Health Research, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
- Department of Science and Engineering, Novel Global Community Educational Foundation, NSW, Australia
| | | | - Sami A Al-Hussain
- Department of Chemistry, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, NSW, Australia
- University Centre for Research & Development, Chandigarh University, Chandigarh-Ludhiana Highway, Mohali, Punjab, India
- Department of Research & Development, Funogen, Athens, Greece
- Department of Research & Development, AFNP Med, Wienna, Austria
| | - George Zouganelis
- School of Human Sciences, College of Life and Natural Sciences, University of Derby, Kedleston Road, Derby, UK
| | - Magdi E A Zaki
- Department of Chemistry, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
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Lewin LE, Daniels KG, Hurst LD. Genes for highly abundant proteins in Escherichia coli avoid 5' codons that promote ribosomal initiation. PLoS Comput Biol 2023; 19:e1011581. [PMID: 37878567 PMCID: PMC10599525 DOI: 10.1371/journal.pcbi.1011581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/09/2023] [Indexed: 10/27/2023] Open
Abstract
In many species highly expressed genes (HEGs) over-employ the synonymous codons that match the more abundant iso-acceptor tRNAs. Bacterial transgene codon randomization experiments report, however, that enrichment with such "translationally optimal" codons has little to no effect on the resultant protein level. By contrast, consistent with the view that ribosomal initiation is rate limiting, synonymous codon usage following the 5' ATG greatly influences protein levels, at least in part by modifying RNA stability. For the design of bacterial transgenes, for simple codon based in silico inference of protein levels and for understanding selection on synonymous mutations, it would be valuable to computationally determine initiation optimality (IO) scores for codons for any given species. One attractive approach is to characterize the 5' codon enrichment of HEGs compared with the most lowly expressed genes, just as translational optimality scores of codons have been similarly defined employing the full gene body. Here we determine the viability of this approach employing a unique opportunity: for Escherichia coli there is both the most extensive protein abundance data for native genes and a unique large-scale transgene codon randomization experiment enabling objective definition of the 5' codons that cause, rather than just correlate with, high protein abundance (that we equate with initiation optimality, broadly defined). Surprisingly, the 5' ends of native genes that specify highly abundant proteins avoid such initiation optimal codons. We find that this is probably owing to conflicting selection pressures particular to native HEGs, including selection favouring low initiation rates, this potentially enabling high efficiency of ribosomal usage and low noise. While the classical HEG enrichment approach does not work, rendering simple prediction of native protein abundance from 5' codon content futile, we report evidence that initiation optimality scores derived from the transgene experiment may hold relevance for in silico transgene design for a broad spectrum of bacteria.
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Affiliation(s)
- Loveday E. Lewin
- The Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Kate G. Daniels
- The Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Laurence D. Hurst
- The Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
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Chung H, Kim J, Lee YJ, Choi KR, Jeong KJ, Kim GJ, Lee SY. Enhanced production of difficult-to-express proteins through knocking down rnpA gene expression. Biotechnol J 2023; 18:e2200641. [PMID: 37285237 DOI: 10.1002/biot.202200641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 05/21/2023] [Accepted: 06/02/2023] [Indexed: 06/09/2023]
Abstract
Escherichia coli has been employed as a workhorse for the efficient production of recombinant proteins. However, some proteins were found to be difficult to produce in E. coli. The stability of mRNA has been considered as one of the important factors affecting recombinant protein production. Here we report a generally applicable and simple strategy for enhancing mRNA stability, and consequently improving recombinant protein production in E. coli. RNase P, a ribozyme comprising an RNA subunit (RnpB) and a protein subunit (RnpA), is involved in tRNA maturation. Based on the finding that purified RnpA can digest rRNA and mRNA in vitro, it was reasoned that knocking down the level of RnpA might enhance recombinant protein production. For this, the synthetic small regulatory RNA-based knockdown system was applied to reduce the expression level of RnpA. The developed RnpA knockdown system allowed successful overexpression of 23 different recombinant proteins of various origins and sizes, including Cas9 protein, antibody fragment, and spider silk protein. Notably, a 284.9-kDa ultra-high molecular weight, highly repetitive glycine-rich spider silk protein, which is one of the most difficult proteins to produce, could be produced to 1.38 g L-1 , about two-fold higher than the highest value previously achieved, by a fed-batch culture of recombinant E. coli strain employing the RnpA knockdown system. The RnpA-knockdown strategy reported here will be generally useful for the production of recombinant proteins including those that have been difficult to produce.
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Affiliation(s)
- Hannah Chung
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- MedicosBiotech Inc, Daejeon, Republic of Korea
| | - Jiyong Kim
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- MedicosBiotech Inc, Daejeon, Republic of Korea
| | - Yong Jae Lee
- Protein Engineering Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Cell Factory Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Republic of Korea
| | - Kyeong Rok Choi
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ki Jun Jeong
- Protein Engineering Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Geun-Joong Kim
- Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 four), Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- MedicosBiotech Inc, Daejeon, Republic of Korea
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Kohl MP, Kompatscher M, Clementi N, Holl L, Erlacher M. Initiation at AUGUG and GUGUG sequences can lead to translation of overlapping reading frames in E. coli. Nucleic Acids Res 2022; 51:271-289. [PMID: 36546769 PMCID: PMC9841429 DOI: 10.1093/nar/gkac1175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/16/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
During initiation, the ribosome is tasked to efficiently recognize open reading frames (ORFs) for accurate and fast translation of mRNAs. A critical step is start codon recognition, which is modulated by initiation factors, mRNA structure, a Shine Dalgarno (SD) sequence and the start codon itself. Within the Escherichia coli genome, we identified more than 50 annotated initiation sites harboring AUGUG or GUGUG sequence motifs that provide two canonical start codons, AUG and GUG, in immediate proximity. As these sites may challenge start codon recognition, we studied if and how the ribosome is accurately guided to the designated ORF, with a special focus on the SD sequence as well as adenine at the fourth coding sequence position (A4). By in vitro and in vivo experiments, we characterized key requirements for unambiguous start codon recognition, but also discovered initiation sites that lead to the translation of both overlapping reading frames. Our findings corroborate the existence of an ambiguous translation initiation mechanism, implicating a multitude of so far unrecognized ORFs and translation products in bacteria.
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Affiliation(s)
- Maximilian P Kohl
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Maria Kompatscher
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Nina Clementi
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lena Holl
- Institute of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Matthias D Erlacher
- To whom correspondence should be addressed. Tel: +43 512900370256; Fax: +43 512900373100;
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Komarova ES, Dontsova OA, Pyshnyi DV, Kabilov MR, Sergiev PV. Flow-Seq Method: Features and Application in Bacterial Translation Studies. Acta Naturae 2022; 14:20-37. [PMID: 36694903 PMCID: PMC9844084 DOI: 10.32607/actanaturae.11820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/11/2022] [Indexed: 01/22/2023] Open
Abstract
The Flow-seq method is based on using reporter construct libraries, where a certain element regulating the gene expression of fluorescent reporter proteins is represented in many thousands of variants. Reporter construct libraries are introduced into cells, sorted according to their fluorescence level, and then subjected to next-generation sequencing. Therefore, it turns out to be possible to identify patterns that determine the expression efficiency, based on tens and hundreds of thousands of reporter constructs in one experiment. This method has become common in evaluating the efficiency of protein synthesis simultaneously by multiple mRNA variants. However, its potential is not confined to this area. In the presented review, a comparative analysis of the Flow-seq method and other alternative approaches used for translation efficiency evaluation of mRNA was carried out; the features of its application and the results obtained by Flow-seq were also considered.
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Affiliation(s)
- E. S. Komarova
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - O. A. Dontsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119234 Russia
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117437 Russia
| | - D. V. Pyshnyi
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090 Russia
| | - M. R. Kabilov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090 Russia
| | - P. V. Sergiev
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119234 Russia
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119234 Russia
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia
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EXPRESSION OF NUCLEOCAPSID VIRAL PROTEINS IN THE BACTERIAL SYSTEM OF Escherichia coli: THE INFLUENCE OF THE CODON COMPOSITION AND THE UNIFORMITY OF ITS DISTRIBUTION WITHIN GENE. BIOTECHNOLOGIA ACTA 2020. [DOI: 10.15407/biotech13.06.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A heterologous host has got a unique expression ability of each gene. Differences between the synonymous sequences play an important role in regulation of protein expression in organisms from Escherichia coli to human, and many details of this process remain unclear. The work was aimed to study the composition of codons, its distribution over the sequence and the effect of rare codons on the expression of viral nucleocapsid proteins and their fragments in the heterologous system of E.coli. The plasmid vector pJC 40 and the BL 21 (DE 3) E. coli strain were used for protein expression. The codon composition analysis was performed using the online resource (www.biologicscorp.com). 10 recombinant polypeptides were obtained encoding the complete nucleotide sequence of nucleocapsid proteins (West Nile and hepatitis C viruses) and the fragments including antigenic determinants (Lassa virus, Marburg, Ebola, Crimean-Congo hemorrhagic fever (CCHF), Puumaravala, Hantaan, and lymphocytic choriomeningitis (LHM)). Hybrid plasmid DNAs provide efficient production of these proteins in the prokaryotic system with the recombinant protein yield varying by a factor of 8: from 5 to 40 mg per 1 liter of bacterial culture. No correlation was found between the level of protein expression and the frequency of occurrence of rare codons in the cloned sequence: the maximum frequency of occurrence of rare codons per cloned sequence was observed for the West Nile virus (14.6%), the minimum was for the CCHF virus (6.6%), whereas the expression level for these proteins was 30 and 5 mg/L culture, respectively. The codon adaptation index (CAI) values, calculated on the basis of the codon composition in E. coli, for the cloned viral sequences were in the range from 0.50 to 0.58, which corresponded to the average expressed proteins. The analysis of the distribution profiles of CAI in the cloned sequences indicated the absence of clusters of rare codons that could create difficulties in translation. A statistically significant difference between the frequencies of the distribution of amino acids in the cloned sequences and their content in E. coli was observed for the nucleocapsid proteins of the Marburg, Ebola, West Nile, and hepatitis C viruses.
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7
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Wons E, Koscielniak D, Szadkowska M, Sektas M. Evaluation of GFP reporter utility for analysis of transcriptional slippage during gene expression. Microb Cell Fact 2018; 17:150. [PMID: 30241530 PMCID: PMC6149199 DOI: 10.1186/s12934-018-0999-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/17/2018] [Indexed: 11/20/2022] Open
Abstract
Background Epimutations arising from transcriptional slippage seem to have more important role in regulating gene expression than earlier though. Since the level and the fidelity of transcription primarily determine the overall efficiency of gene expression, all factors contributing to their decrease should be identified and optimized. Results To examine the influence of A/T homopolymeric sequences on introduction of erroneous nucleotides by slippage mechanism green fluorescence protein (GFP) reporter was chosen. The in- or out-of-frame gfp gene was fused to upstream fragment with variable number of adenine or thymine stretches resulting in several hybrid GFP proteins with diverse amino acids at N-terminus. Here, by using T7 phage expression system we showed that the intensity of GFP fluorescence mainly depends on the number of the retained natural amino acids. While the lack of serine (S2) residue results in negligible effects, the lack of serine and lysine (S2K3) contributed to a significant reduction in fluorescence by 2.7-fold for polyA-based in-frame controls and twofold for polyTs. What is more, N-terminal tails amino acid composition was rather of secondary importance, since the whole-cell fluorescence differed in a range of 9–18% between corresponding polyA- and polyT-based constructs. Conclusions Here we present experimental evidence for utility of GFP reporter for accurate estimation of A/T homopolymeric sequence contribution in transcriptional slippage induction. We showed that the intensity of GFP hybrid fluorescence mainly depends on the number of retained natural amino acids, thus fluorescence raw data need to be referred to appropriate positive control. Moreover, only in case of GFP hybrids with relatively short N-terminal tags the fluorescence level solely reflects production yield, what further indicates the impact of an individual slippage sequence. Our results demonstrate that in contrast to the E. coli enzyme, T7 RNA polymerase exhibits extremely high propensity to slippage even on runs as short as 3 adenine or 4 thymine residues. Electronic supplementary material The online version of this article (10.1186/s12934-018-0999-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ewa Wons
- Department of Microbiology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland
| | - Dawid Koscielniak
- Department of Microbiology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland
| | - Monika Szadkowska
- Department of Microbiology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland
| | - Marian Sektas
- Department of Microbiology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland.
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Park YJ, Lee KH, Baek MS, Kim DM. High-throughput engineering of initial coding regions for maximized production of recombinant proteins. BIOTECHNOL BIOPROC E 2017. [DOI: 10.1007/s12257-017-0344-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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9
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Kasi D, Nah HJ, Catherine C, Kim ES, Han K, Ha JC, Kim DM. Enhanced Production of Soluble Recombinant Proteins With an In Situ-Removable Fusion Partner in a Cell-Free Synthesis System. Biotechnol J 2017; 12. [PMID: 28891200 DOI: 10.1002/biot.201700125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 08/12/2017] [Indexed: 12/17/2022]
Abstract
High-yield production of soluble protein is a common concern in diverse fields of biotechnology. In this study, a strategy of using an engineered nucleotide sequence of ubiquitin for enhancing the production of soluble proteins in a cell-free synthesis system is presented. When examined for a series of proteins that otherwise were poorly expressed, N-terminal fusion with ubiquitin significantly increased both the expression levels and solubility of the translational products. The effect of ubiquitin fusion was also markedly augmented by engineering the nucleotide sequence of ubiquitin, leading to several fold enhancements in soluble production of target proteins. Recombinant proteins were produced with their native amino acid sequences through in situ removal of ubiquitin during cell-free synthesis reactions in the presence of a deubiquitinase. The presented strategy could be employed as a facile route to prepare soluble proteins required for various applications.
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Affiliation(s)
- Devi Kasi
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-ro, Daejeon 34134, Korea
| | - Hee Ju Nah
- Department of Biological Engineering, Inha University, Incheon, Korea
| | | | - Eung-Soo Kim
- Department of Biological Engineering, Inha University, Incheon, Korea
| | | | | | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-ro, Daejeon 34134, Korea
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Ramkumar S, Rabindranath Pai V, Thangadurai C, Priya Murugan V. Chemical complexity of protein determines optimal E. coli expression host; A comparative study using Erythropoietin, Streptokinase and Tumor Necrosis Factor Receptor. J Genet Eng Biotechnol 2017; 15:179-185. [PMID: 30647654 PMCID: PMC6296564 DOI: 10.1016/j.jgeb.2016.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/03/2016] [Accepted: 12/19/2016] [Indexed: 12/01/2022]
Abstract
High throughput expression of proteins is often hampered by the failure of certain proteins to express in the particular E. coli host strain used for the study. The identification of a host strain compatible for a wide variety of proteins is desirable. In this study, the recombinant expression of therapeutic proteins Erythropoietin (EPO), Streptokinase (SK) and Tumor Necrosis Factor Receptor Extra cellular domain (TNFR ED) that vary widely in their chemical nature was studied in four different strains of E. coli namely BL21 (DE3), BL21 (DE3) pLys S, BL21 (DE3) Rosetta pLys S and GJ1158. Since there are no previous report for the analysis of expression and solubility of the above mentioned proteins we studied the same in various E. coli stains. Here we report that E. coli strain GJ1158 which uses salt induction was found to be the most suitable for overexpression of all the three proteins. Interestingly rare codons were found not to play any significant role in the expression. Protein toxicity and aggregation propensity were also studied. One of the major factors influencing expression was the tendency of the protein to aggregate which in turn influences folding and toxicity levels. The solubility of the proteins was inversely proportional to aggregation. Expression levels were in the order of TNFR ED < EPO < SK. In conclusion, it was observed that E. coli GJ1158, a strain known to decrease aggregation of proteins was found to be more suited for expression. This is the first time GJ1158 has been included in this kind of analysis for comparison of protein expression in various E. coli hosts.
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Affiliation(s)
- Subramani Ramkumar
- Genetic Engineering Unit, Centre for Biotechnology, Anna University, Sardar Patel Road, Guindy, Chennai 600 025, India
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11
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Ojima-Kato T, Nagai S, Nakano H. N-terminal SKIK peptide tag markedly improves expression of difficult-to-express proteins in Escherichia coli and Saccharomyces cerevisiae. J Biosci Bioeng 2017; 123:540-546. [DOI: 10.1016/j.jbiosc.2016.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/23/2016] [Accepted: 12/06/2016] [Indexed: 11/27/2022]
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12
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Zhong C, Wei P, Zhang YHP. Enhancing functional expression of codon-optimized heterologous enzymes in Escherichia coli BL21(DE3) by selective introduction of synonymous rare codons. Biotechnol Bioeng 2016; 114:1054-1064. [PMID: 27943233 DOI: 10.1002/bit.26238] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 12/12/2022]
Abstract
Rare codon in a heterologous gene may cause premature termination of protein synthesis, misincorporation of amino acids, and/or slow translation of mRNA, decreasing the heterologous protein expression. However, its hypothetical function pertaining to functional protein folding has been barely reported. Here, we investigated the effects of selective introduction of synonymous rare codons (SRCs) to two codon-optimized (i.e., rare codon-free) genes sucrose phosphorylase (SP) gene from Thermoanaerobacterium thermosaccharolyticum and amidohydrolase gene from Streptomyces caatingaensis on their expression levels in Escherichia coli BL21(DE3). We investigated the introduction of a single SRC to the coding regions of alpha-helix, beta-strand, or linker in the first half of rare codon-free sp and ah gene. The introduction of a single SRC in the beginning of the coding regions of beta-strand greatly enhanced their soluble expression levels as compared to the other regions. Also, we applied directed evolution to test multi-SRC-containing sp gene mutants for enhanced soluble SP expression levels. To easily identify the soluble SP expression level of colonies growing on Petri dishes, mCherry fluorescent protein was used as a SP-folding reporter when it was fused to the 3' end of the sp gene mutant libraries. After three rounds of screening, the best sp gene mutant containing nine SRCs exhibited an approximately six-fold enhancement in soluble protein expression level as compared to the wild-type and rare codon-free sp control. This study suggests that the selective introduction of SRCs can attenuate translation at specific points and such discontinuous attenuation can temporally separate the translation of segments of the peptide chains and actively coordinates their co-translational folding, resulting in enhanced functional protein expression. Biotechnol. Bioeng. 2017;114: 1054-1064. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Chao Zhong
- Department of Biological Systems Engineering, Virginia Tech, 304 Seitz Hall, Blacksburg, Virginia, 24061.,College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Ping Wei
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Yi-Heng Percival Zhang
- Department of Biological Systems Engineering, Virginia Tech, 304 Seitz Hall, Blacksburg, Virginia, 24061.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
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Karimi Z, Nezafat N, Negahdaripour M, Berenjian A, Hemmati S, Ghasemi Y. The effect of rare codons following the ATG start codon on expression of human granulocyte-colony stimulating factor in Escherichia coli. Protein Expr Purif 2015; 114:108-14. [DOI: 10.1016/j.pep.2015.05.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 05/27/2015] [Accepted: 05/29/2015] [Indexed: 10/23/2022]
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14
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Rodrigues JL, Prather KLJ, Kluskens LD, Rodrigues LR. Heterologous production of curcuminoids. Microbiol Mol Biol Rev 2015; 79:39-60. [PMID: 25631288 PMCID: PMC4402967 DOI: 10.1128/mmbr.00031-14] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
SUMMARY Curcuminoids, components of the rhizome of turmeric, show several beneficial biological activities, including anticarcinogenic, antioxidant, anti-inflammatory, and antitumor activities. Despite their numerous pharmaceutically important properties, the low natural abundance of curcuminoids represents a major drawback for their use as therapeutic agents. Therefore, they represent attractive targets for heterologous production and metabolic engineering. The understanding of biosynthesis of curcuminoids in turmeric made remarkable advances in the last decade, and as a result, several efforts to produce them in heterologous organisms have been reported. The artificial biosynthetic pathway (e.g., in Escherichia coli) can start with the supplementation of the amino acid tyrosine or phenylalanine or of carboxylic acids and lead to the production of several natural curcuminoids. Unnatural carboxylic acids can also be supplemented as precursors and lead to the production of unnatural compounds with possibly novel therapeutic properties. In this paper, we review the natural conversion of curcuminoids in turmeric and their production by E. coli using an artificial biosynthetic pathway. We also explore the potential of other enzymes discovered recently or already used in other similar biosynthetic pathways, such as flavonoids and stilbenoids, to increase curcuminoid yield and activity.
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Affiliation(s)
- J L Rodrigues
- Centre of Biological Engineering, University of Minho, Braga, Portugal MIT-Portugal Program, Cambridge, Massachusetts, USA, and Lisbon, Portugal
| | - K L J Prather
- Department of Chemical Engineering, Synthetic Biology Engineering Research Center, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA MIT-Portugal Program, Cambridge, Massachusetts, USA, and Lisbon, Portugal
| | - L D Kluskens
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - L R Rodrigues
- Centre of Biological Engineering, University of Minho, Braga, Portugal MIT-Portugal Program, Cambridge, Massachusetts, USA, and Lisbon, Portugal
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15
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Cheong DE, Ko KC, Han Y, Jeon HG, Sung BH, Kim GJ, Choi JH, Song JJ. Enhancing functional expression of heterologous proteins through random substitution of genetic codes in the 5' coding region. Biotechnol Bioeng 2015; 112:822-6. [PMID: 25323933 DOI: 10.1002/bit.25478] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 02/03/2023]
Abstract
Recent studies using heterologous protein expression systems suggest that synonymous codons affect not only the expression but also the properties of the expressed protein. However, practical application of this information is challenging, and to date, efforts to employ bioinformatics tools to design synonymous codon mixes have been only marginally successful. Here, we sought to enhance the functional expression of heterologous protein in Escherichia coli through completely random substitution of the first ten codons with synonymous codons, using a previously isolated exocellulase CelEdx-SF301 as the model protein. Synonymous codon variants were generated by PCR using forward primers with mixed nucleotides at the third position in each codon and a conventional reverse primer. The resulting PCR products were inserted upstream of the fluorescent protein mCherry without linkers. After transformation and cultivation, colonies exhibiting red fluorescence were selected, and the activity of SF301-mCherry fusion proteins was tested. Synonymous codon variant fusion proteins exhibited 35- to 530-fold increases in functional expression compared with wild-type controls. Unlike results from other reports, we found that the stability of mRNA secondary structure in the 5' untranslated region and codon rarity were not correlated with functional expression level. Our work demonstrates that a completely random mixed of synonymous codons effectively enhances functional expression levels without the need for amino acid substitutions.
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Affiliation(s)
- Dae-Eun Cheong
- Industrial Microbiology & Bioprocess Research Center, Integrated Biorefinery Research Institute, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 181 Ipsin-gil, Jeongeup-si, Jeonbuk, 580-185, Republic of Korea
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16
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Faiq MA, Ali M, Dada T, Dada R, Saluja D. A novel methodology for enhanced and consistent heterologous expression of unmodified human cytochrome P450 1B1 (CYP1B1). PLoS One 2014; 9:e110473. [PMID: 25329831 PMCID: PMC4199734 DOI: 10.1371/journal.pone.0110473] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 09/08/2014] [Indexed: 12/29/2022] Open
Abstract
Cytochrome P450 1B1 (CYP1B1) is a universal cancer marker and is implicated in many other disorders. Mutations in CYP1B1 are also associated with childhood blindness due to primary congenital glaucoma (PCG). To understand the CYP1B1 mediated etiopathology of PCG and pathomechanism of various cancers, it is important to carry out its functional studies. Heterologous expression of CYP1B1 in prokaryotes is imperative because bacteria yield a higher amount of heterologous proteins in lesser time and so the expressed protein is ideal for functional studies. In such expression system there is no interference by other eukaryotic proteins. But the story is not that simple as expression of heterologous CYP1B1 poses many technical difficulties. Investigators have employed various modifications/deletions of CYP N-terminus to improve CYP1B1 expression. However, the drawback of these studies is that it changes the original protein and, as a result, invalidates functional studies. The present study examines the role of various conditions and reagents in successful and consistent expression of sufficient quantities of unmodified/native human CYP1B1 in E. coli. We aimed at expressing CYP1B1 in various strains of E. coli and in the course developed a protocol that results in high expression of unmodified protein sufficient for functional/biophysical studies. We examined CYP1B1 expression with respect to different expression vectors, bacterial strains, types of culture media, time, Isopropyl β-D-1-thiogalactopyranoside concentrations, temperatures, rotations per minute, conditioning reagents and the efficacy of a newly described technique called double colony selection. We report a protocol that is simple, easy and can be carried out in any laboratory without the requirement of a fermentor. Though employed for CYP1B1 expression, this protocol can ideally be used to express any eukaryotic membrane protein.
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Affiliation(s)
- Muneeb A. Faiq
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
- Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, North Campus, Delhi, India
- Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, All India Institute of Medical Sciences, Ansari Nagar, India
| | - Mashook Ali
- Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, North Campus, Delhi, India
| | - Tanuj Dada
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Rima Dada
- Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, All India Institute of Medical Sciences, Ansari Nagar, India
| | - Daman Saluja
- Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, North Campus, Delhi, India
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Indiveri C, Galluccio M, Scalise M, Pochini L. Strategies of bacterial over expression of membrane transporters relevant in human health: the successful case of the three members of OCTN subfamily. Mol Biotechnol 2013; 54:724-36. [PMID: 22843325 PMCID: PMC3636443 DOI: 10.1007/s12033-012-9586-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The OCTN subfamily includes OCTN1, 2, and 3 which are structurally and functionally related. These transporters are involved in maintenance of the carnitine homeostasis, which is essential in mammals for fatty acid β-oxidation, VLDL assembly, post-translational modifications, and other essential functions. Indeed, defects of these transporters lead to severe pathologies. OCTN1 and OCTN2 are expressed in many human tissues, while OCTN3 gene has been identified only in mouse and rat. The transporters mediate transport of carnitine and other substrates with different efficiencies and mechanisms. In order to over express the three proteins, a screening of many combinations of E. coli strains with plasmid constructs has been conducted. Only Rosetta(DE3) or Rosettagami2(DE3) gave significant expression. Higher protein amounts were firstly obtained with pET-41a(+) or pGEX-4T1 carrying fusion protein tags which required additional purification passages. Vectors carrying only a 6His tag, suitable for single passage purification, were preferred even though they lead to lower initial expression levels. Expressions were then increased optimizing several critical parameters. hOCTN1 was obtained with pH6EX3 in RosettaGami2(DE3)pLysS. hOCTN2 and mOCTN3 were obtained using pET-21a(+) in Rosetta(DE3). In particular, hOCTN2 was expressed only after codon bias, substituting the second triplet CGG with AAA (R2K mutant). The best growth conditions for hOCTN1 and mOCTN3 were 28 °C and 6 h of induction, while 4 h of induction for hOCTN2R2K. The proteins collected in the insoluble fraction of cell lysates, solubilized with sarkosyl, were purified by Ni-chelating chromatography. Final yield was 2.0, 3.0, or 3.5 mg/l of cell culture for mOCTN3, hOCTN1, or hOCTN2R2K. The data indicated that, in spite of the close evolutionary relations, several factors play different critical roles in bacterial expression of the three proteins, thus general criteria cannot be underlined. However, the strategy of dealing with related proteins revealed to be finally successful for over expressing all the three subfamily members.
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Affiliation(s)
- Cesare Indiveri
- Department of Cell Biology, University of Calabria, Arcavacata di Rende, Italy.
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Recombinant polypeptide production in E. coli: towards a rational approach to improve the yields of functional proteins. Microb Cell Fact 2013; 12:101. [PMID: 24176192 PMCID: PMC3832250 DOI: 10.1186/1475-2859-12-101] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 10/30/2013] [Indexed: 11/16/2022] Open
Abstract
The development of complementary technologies enabled the successful production of recombinant polypeptides in bacteria and opened to biology researchers new avenues as obtaining suitable amounts of proteins necessary for their experimental work became easy, fast, and inexpensive. Nevertheless, the recombinant approach remained somehow unpredictable, since many constructs resisted to apparent production or accumulated as aggregates. Several factors and physical/chemical conditions that could improve the accumulation of native-like protein were identified. At the same time, it was acknowledged that the outcome of most of them was erratic and that almost any protein required its own specific optimized set of conditions to achieve its correct folding. The attempt to understand the critical points specific for recombinant protein production missed the goal of setting universally useful protocols, but contributed to the increase of the rate of success by proposing always new empiric combinations. Nevertheless, the results published in the recent literature allow for a better comprehension of some key mechanisms controlling protein production in E. coli and could enable the elaboration of rational methodologies for improving the quantitative and qualitative features of the produced polypeptides. This result will be achieved when the identification of the limiting step that impairs the accomplishment of the native folding for any single construct will become straightforward. This minireview will discuss how factors such as the expression rate, the folding machinery, and the secretion efficiency may impact the final protein yields.
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Tumulka F, Roos C, Löhr F, Bock C, Bernhard F, Dötsch V, Abele R. Conformational stabilization of the membrane embedded targeting domain of the lysosomal peptide transporter TAPL for solution NMR. JOURNAL OF BIOMOLECULAR NMR 2013; 57:141-154. [PMID: 24013930 DOI: 10.1007/s10858-013-9774-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/21/2013] [Indexed: 06/02/2023]
Abstract
The ATP binding cassette transporter TAPL translocates cytosolic peptides into the lumen of lysosomes driven by the hydrolysis of ATP. Functionally, this transporter can be divided into coreTAPL, comprising the transport function, and an additional N-terminal transmembrane domain called TMD0, which is essential for lysosomal targeting and mediates the interaction with the lysosomal associated membrane proteins LAMP-1 and LAMP-2. To elucidate the structure of this unique domain, we developed protocols for the production of high quantities of cell-free expressed TMD0 by screening different N-terminal expression tags. Independently of the amino acid sequence, high expression was detected for AU-rich sequences in the first seven codons, decreasing the free energy of RNA secondary structure formation at translation initiation. Furthermore, avoiding NGG codons in the region of translation initiation demonstrated a positive effect on expression. For NMR studies, conditions were optimized for high solubilization efficiency, long-term stability, and high quality spectra. A most critical step was the careful exchange of the detergent used for solubilization by the detergent dihexanoylphosphatidylcholine. Several constructs of different size were tested in order to stabilize the fold of TMD0 as well as to reduce the conformation exchange. NMR spectra with sufficient resolution and homogeneity were finally obtained with a TMD0 derivative only modified by a C-terminal His10-tag and containing a codon optimized AT-rich sequence.
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Affiliation(s)
- Franz Tumulka
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt am Main, Germany
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20
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Design and optimization of short DNA sequences that can be used as 5' fusion partners for high-level expression of heterologous genes in Escherichia coli. Appl Environ Microbiol 2013; 79:6655-64. [PMID: 23974137 DOI: 10.1128/aem.01676-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The 5' terminal nucleotide sequence of a gene is often a bottleneck in recombinant protein production. The ifn-α2bS gene is poorly expressed in Escherichia coli unless a translocation signal sequence (pelB) is fused to the 5' end of the gene. A combined in silico and in vivo analysis reported here further indicates that the ifn-α2bS 5' coding sequence is suboptimal for efficient gene expression. ifn-α2bS therefore presents a suitable model gene for describing properties of 5' fusions promoting expression. We show that short DNA sequences corresponding to the 5' end of the highly expressed celB gene, whose protein product is cytosolic, can functionally replace pelB as a 5' fusion partner for efficient ifn-α2bS expression. celB fusions of various lengths (corresponding to a minimum of 8 codons) led to more than 7- and 60-fold stimulation of expression at the transcript and protein levels, respectively. Moreover, the presence of a celB-based fusion partner was found to moderately reduce the decay rate of the corresponding transcript. The 5' fusions thus appear to act by enhancing translation, and bound ribosomes may accordingly contribute to increased mRNA stability and reduced mRNA decay. However, other effects, such as altered protein stability, cannot be excluded. We also developed an experimental protocol that enabled us to identify improved variants of the celB fusion, and one of these (celBD11) could be used to additionally increase ifn-α2bS expression more than 4-fold at the protein level. Interestingly, celBD11 also stimulated greater protein production of three other medically important human genes than the wild-type celB fragment.
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21
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Recycling of peptidyl-tRNAs by peptidyl-tRNA hydrolase counteracts azithromycin-mediated effects on Pseudomonas aeruginosa. Antimicrob Agents Chemother 2013; 57:1617-24. [PMID: 23318806 DOI: 10.1128/aac.02582-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Acute and chronic infections caused by the opportunistic pathogen Pseudomonas aeruginosa pose a serious threat to human health worldwide, and its increasing resistance to antibiotics requires alternative treatments that are more effective than available strategies. Clinical studies have clearly demonstrated that cystic fibrosis (CF) patients with chronic P. aeruginosa infections benefit from long-term low-dose azithromycin (AZM) treatment. Immunomodulating activity, the impact of AZM on the expression of quorum-sensing-dependent virulence factors, type three secretion, and motility in P. aeruginosa seem to contribute to the therapeutic response. However, to date, the molecular mechanisms underlying these AZM effects have remained elusive. Our data indicate that the AZM-mediated phenotype is caused by a depletion of the intracellular pools of tRNAs available for protein synthesis. Overexpression of the P. aeruginosa peptidyl-tRNA hydrolase, which recycles the tRNA from peptidyl-tRNA drop-off during translation, counteracted the effects of AZM on stationary-phase cell killing, cytotoxicity, and the production of rhamnolipids and partially restored swarming motility. Intriguingly, the exchange of a rare for a frequent codon in rhlR also explicitly diminished the AZM-mediated decreased production of rhamnolipids. These results indicate that depletion of the tRNA pools by AZM seems to affect the translation of genes that use rare aminoacyl-tRNA isoacceptors to a great extent and might explain the selective activity of AZM on the P. aeruginosa proteome and possibly also on the protein expression profiles of other bacterial pathogens.
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Monshupanee T, Johansen SK, Dahlberg AE, Douthwaite S. Capreomycin susceptibility is increased by TlyA-directed 2'-O-methylation on both ribosomal subunits. Mol Microbiol 2012; 85:1194-203. [PMID: 22779429 DOI: 10.1111/j.1365-2958.2012.08168.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The binding site of the cyclic peptide antibiotics capreomycin and viomycin is located on the ribosomal subunit interface close to nucleotides C1409 in 16S rRNA and C1920 in 23S rRNA. In Mycobacterium tuberculosis, the 2'-hydroxyls of both nucleotides are methylated by the enzyme TlyA. Loss of these methylations through inactivation of TlyA confers resistance to capreomycin and viomycin. We report here that TlyA orthologues occur in diverse bacteria and fall into two distinct groups. One group, now termed TlyA(I) , has shorter N- and C-termini and methylates only C1920; the second group (now TlyA(II) ) includes the mycobacterial enzyme, and these longer orthologues methylate at both C1409 and C1920. Ribosomal subunits are the preferred substrates for both groups of orthologues. Amino acid substitutions at the N-terminus of TlyA(II) reduce its ability to methylate these substrates. Growing pairs of recombinant TlyA(II) Escherichia coli strains in competition shows that even subtle changes in the level of rRNA methylation lead to significant differences in susceptibility to sub-inhibitory concentrations of capreomycin. The findings reveal that 2'-O-methyls at both C1409 and C1920 play a role in facilitating the inhibitory effects of capreomycin and viomycin on the bacterial ribosome.
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Affiliation(s)
- Tanakarn Monshupanee
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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23
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Loh E, Memarpour F, Vaitkevicius K, Kallipolitis BH, Johansson J, Sondén B. An unstructured 5'-coding region of the prfA mRNA is required for efficient translation. Nucleic Acids Res 2011; 40:1818-27. [PMID: 22053088 PMCID: PMC3287183 DOI: 10.1093/nar/gkr850] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Expression of virulence factors in the human bacterial pathogen Listeria monocytogenes is almost exclusively regulated by the transcriptional activator PrfA. The translation of prfA is controlled by a thermosensor located in the 5′-untranslated RNA (UTR), and is high at 37°C and low at temperatures <30°C. In order to develop a thermoregulated translational expression system, the 5′-UTR and different lengths of the prfA-coding sequences were placed in front of lacZ. When expressed in Escherichia coli, the β-galactosidase expression was directly correlated to the length of the prfA-coding mRNA lying in front of lacZ. A similar effect was detected with gfp as a reporter gene in both L. monocytogenes and E. coli, emphasizing the requirement of the prfA-coding RNA for maximal expression. In vitro transcription/translation and mutational analysis suggests a role for the first 20 codons of the native prfA-mRNA for maximal expression. By toe-print and RNA-probing analysis, a flexible hairpin-loop located immediately downstream of the start-codon was shown to be important for ribosomal binding. The present work determines the importance of an unstructured part of the 5′-coding region of the prfA-mRNA for efficient translation.
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Affiliation(s)
- Edmund Loh
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, 90187 Umeå, Sweden
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Ahn JH, Keum JW, Kim DM. Expression screening of fusion partners from an E. coli genome for soluble expression of recombinant proteins in a cell-free protein synthesis system. PLoS One 2011; 6:e26875. [PMID: 22073212 PMCID: PMC3206877 DOI: 10.1371/journal.pone.0026875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2011] [Accepted: 10/05/2011] [Indexed: 12/04/2022] Open
Abstract
While access to soluble recombinant proteins is essential for a number of proteome studies, preparation of purified functional proteins is often limited by the protein solubility. In this study, potent solubility-enhancing fusion partners were screened from the repertoire of endogenous E. coli proteins. Based on the presumed correlation between the intracellular abundance and folding efficiency of proteins, PCR-amplified ORFs of a series of highly abundant E. coli proteins were fused with aggregation-prone heterologous proteins and then directly expressed for quantitative estimation of the expression efficiency of soluble translation products. Through two-step screening procedures involving the expression of 552 fusion constructs targeted against a series of cytokine proteins, we were able to discover a number of endogenous E. coli proteins that dramatically enhanced the soluble expression of the target proteins. This strategy of cell-free expression screening can be extended to quantitative, global analysis of genomic resources for various purposes.
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Affiliation(s)
- Jin-Ho Ahn
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, Republic of Korea
| | - Jung-Won Keum
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea
| | - Dong-Myung Kim
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, Republic of Korea
- * E-mail:
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25
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Enhancing the recombinant protein expression of halohydrin dehalogenase HheA in Escherichia coli by applying a codon optimization strategy. Enzyme Microb Technol 2011; 49:395-401. [DOI: 10.1016/j.enzmictec.2011.06.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/20/2011] [Accepted: 06/25/2011] [Indexed: 11/21/2022]
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26
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Tsao D, Shabalina SA, Gauthier J, Dokholyan NV, Diatchenko L. Disruptive mRNA folding increases translational efficiency of catechol-O-methyltransferase variant. Nucleic Acids Res 2011; 39:6201-12. [PMID: 21486747 PMCID: PMC3152328 DOI: 10.1093/nar/gkr165] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Catechol-O-methyltransferase (COMT) is a major enzyme controlling catecholamine levels that plays a central role in cognition, affective mood and pain perception. There are three common COMT haplotypes in the human population reported to have functional effects, divergent in two synonymous and one nonsynonymous position. We demonstrate that one of the haplotypes, carrying the non-synonymous variation known to code for a less stable protein, exhibits increased protein expression in vitro. This increased protein expression, which would compensate for lower protein stability, is solely produced by a synonymous variation (C166T) situated within the haplotype and located in the 5′ region of the RNA transcript. Based on mRNA secondary structure predictions, we suggest that structural destabilization near the start codon caused by the T allele could be related to the observed increase in COMT expression. Our folding simulations of the tertiary mRNA structures demonstrate that destabilization by the T allele lowers the folding transition barrier, thus decreasing the probability of occupying its native state. These data suggest a novel structural mechanism whereby functional synonymous variations near the translation initiation codon affect the translation efficiency via entropy-driven changes in mRNA dynamics and present another example of stable compensatory genetic variations in the human population.
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Affiliation(s)
- Douglas Tsao
- Department of Chemistry, Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599, USA
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27
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Reduced stability of mRNA secondary structure near the translation-initiation site in dsDNA viruses. BMC Evol Biol 2011; 11:59. [PMID: 21385374 PMCID: PMC3072339 DOI: 10.1186/1471-2148-11-59] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 03/07/2011] [Indexed: 11/21/2022] Open
Abstract
Background Recent studies have demonstrated a selection pressure for reduced mRNA secondary-structure stability near the start codon of coding sequences. This selection pressure can be observed in bacteria, archaea, and eukaryotes, and is likely caused by the requirement of efficient translation initiation in cellular organism. Results Here, we surveyed the complete genomes of 650 dsDNA virus strains for signals of reduced stability of mRNA secondary structure near the start codon. Our analysis included viruses infecting eukaryotic, prokaryotic, and archaeic hosts. We found that many viruses showed evidence for reduced mRNA secondary-structure stability near the start codon. The effect was most pronounced in viruses infecting prokaryotes, but was also observed in viruses infecting eukaryotes and archaea. The reduction in stability generally increased with increasing genomic GC content. For bacteriophage, the reduction was correlated with a corresponding reduction of stability in the phage hosts. Conclusions We conclude that reduced stability of the mRNA secondary structure near the start codon is a common feature for dsDNA viruses, likely driven by the same selective pressures that cause it in cellular organisms.
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28
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Shemesh R, Novik A, Cohen Y. Follow the leader: preference for specific amino acids directly following the initial methionine in proteins of different organisms. GENOMICS PROTEOMICS & BIOINFORMATICS 2011; 8:180-9. [PMID: 20970746 PMCID: PMC5054127 DOI: 10.1016/s1672-0229(10)60020-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
It is well established that the vast majority of proteins of all taxonomical groups and species are initiated by an AUG codon, translated into the amino acid methionine (Met). Many attempts were made to evaluate the importance of the sequences surrounding the initiation codon, mostly focusing on the RNA sequence. However, the role and importance of the amino acids following the initiating Met residue were rarely investigated, mostly in bacteria and fungi. Herein, we computationally examined the protein sequences of all major taxonomical groups represented in the Swiss-Prot database, and evaluated the preference of each group to specific amino acids at the positions directly following the initial Met. The results indicate that there is a species-specific preference for the second amino acid of the majority of protein sequences. Interestingly, the preference for a certain amino acid at the second position changes throughout evolution from lysine in prokaryotes, through serine in lower eukaryotes, to alanine in higher plants and animals.
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Welch M, Villalobos A, Gustafsson C, Minshull J. Designing genes for successful protein expression. Methods Enzymol 2011; 498:43-66. [PMID: 21601673 DOI: 10.1016/b978-0-12-385120-8.00003-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
DNA sequences are now far more readily available in silico than as physical DNA. De novo gene synthesis is an increasingly cost-effective method for building genetic constructs, and effectively removes the constraint of basing constructs on extant sequences. This allows scientists and engineers to experimentally test their hypotheses relating sequence to function. Molecular biologists, and now synthetic biologists, are characterizing and cataloging genetic elements with specific functions, aiming to combine them to perform complex functions. However, the most common purpose of synthetic genes is for the expression of an encoded protein. The huge number of different proteins makes it impossible to characterize and catalog each functional gene. Instead, it is necessary to abstract design principles from experimental data: data that can be generated by making predictions followed by synthesizing sequences to test those predictions. Because of the degeneracy of the genetic code, design of gene sequences to encode proteins is a high-dimensional problem, so there is no single simple formula to guarantee success. Nevertheless, there are several straightforward steps that can be taken to greatly increase the probability that a designed sequence will result in expression of the encoded protein. In this chapter, we discuss gene sequence parameters that are important for protein expression. We also describe algorithms for optimizing these parameters, and troubleshooting procedures that can be helpful when initial attempts fail. Finally, we show how many of these methods can be accomplished using the synthetic biology software tool Gene Designer.
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Affiliation(s)
- Mark Welch
- DNA2.0, Inc., Suite A, Menlo Park, California, USA
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30
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Goltermann L, Borch Jensen M, Bentin T. Tuning protein expression using synonymous codon libraries targeted to the 5′ mRNA coding region. Protein Eng Des Sel 2010; 24:123-9. [DOI: 10.1093/protein/gzq086] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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31
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Bivona L, Zou Z, Stutzman N, Sun PD. Influence of the second amino acid on recombinant protein expression. Protein Expr Purif 2010; 74:248-56. [PMID: 20600944 DOI: 10.1016/j.pep.2010.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/15/2010] [Accepted: 06/15/2010] [Indexed: 11/25/2022]
Abstract
Factors affecting protein expression have been intensely studied to the benefit of recombinant protein production. Through mutational analysis at the +2 amino acid position of recombinant Igα, we examined the effect of all 20 amino acids on protein expression. The results showed that amino acids at the +2 position affected 10-fold in the recombinant protein expression. Specifically, Ala, Cys, Pro, Ser, Thr, and Lys at the +2 position resulted in significantly higher expression of recombinant Igα than other amino acids, while Met, His and Glu resulted in greatly reduced protein expression. This expression difference depended on the amino acid instead of their codon usage. Consistent with the mutational results, a statistically significant enrichment in Ala and Ser at the +2 position was observed among highly expressed Escherichia coli genes. This work suggests a general approach to enhance protein expression by incorporating an Ala or Ser after the initiation codon.
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Affiliation(s)
- Louis Bivona
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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Gu W, Zhou T, Wilke CO. A universal trend of reduced mRNA stability near the translation-initiation site in prokaryotes and eukaryotes. PLoS Comput Biol 2010; 6:e1000664. [PMID: 20140241 PMCID: PMC2816680 DOI: 10.1371/journal.pcbi.1000664] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 12/30/2009] [Indexed: 12/05/2022] Open
Abstract
Recent studies have suggested that the thermodynamic stability of mRNA secondary structure near the start codon can regulate translation efficiency in Escherichia coli, and that translation is more efficient the less stable the secondary structure. We survey the complete genomes of 340 species for signals of reduced mRNA secondary structure near the start codon. Our analysis includes bacteria, archaea, fungi, plants, insects, fishes, birds, and mammals. We find that nearly all species show evidence for reduced mRNA stability near the start codon. The reduction in stability generally increases with increasing genomic GC content. In prokaryotes, the reduction also increases with decreasing optimal growth temperature. Within genomes, there is variation in the stability among genes, and this variation correlates with gene GC content, codon bias, and gene expression level. For birds and mammals, however, we do not find a genome-wide trend of reduced mRNA stability near the start codon. Yet the most GC rich genes in these organisms do show such a signal. We conclude that reduced stability of the mRNA secondary structure near the start codon is a universal feature of all cellular life. We suggest that the origin of this reduction is selection for efficient recognition of the start codon by initiator-tRNA. Synonymous mutations are mutations that change the nucleotide sequence of a gene without changing the amino-acid sequence. Because these mutations don't alter the expressed protein, they are frequently also called silent mutations. Yet increasing evidence demonstrates that synonymous mutations are not that silent. In particular, experimental work in Escherichia coli has shown that the choice of synonymous codons near the start codon can greatly influence protein production. Codons that allow the mRNA to fold into a stable secondary structure seem to inhibit efficient translation initiation. This observation suggests that selection should prefer reduced mRNA stability near the start codon in many organisms. Here, we show that this prediction generally holds true in most organisms, including bacteria, archaea, fungi, plants, insects, and fishes. In birds and mammals it doesn't hold true genome-wide, but it does hold true in the most GC-rich genes. In all organisms, the extent to which mRNA stability is reduced increases with increasing GC content. In prokaryotes, it also increases with decreasing optimal growing temperature. Thus, it seems that all organisms have to optimize their synonymous sites near the start codon to guarantee efficient protein translation.
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Affiliation(s)
- Wanjun Gu
- Key Laboratory of Child Development and Learning Science of Ministry of Education of China, Southeast University, Nanjing, Jiangsu, China
| | - Tong Zhou
- Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America
- Section of Integrative Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Claus O. Wilke
- Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America
- Section of Integrative Biology, The University of Texas at Austin, Austin, Texas, United States of America
- Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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Welch M, Govindarajan S, Ness JE, Villalobos A, Gurney A, Minshull J, Gustafsson C. Design parameters to control synthetic gene expression in Escherichia coli. PLoS One 2009; 4:e7002. [PMID: 19759823 PMCID: PMC2736378 DOI: 10.1371/journal.pone.0007002] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 08/17/2009] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Production of proteins as therapeutic agents, research reagents and molecular tools frequently depends on expression in heterologous hosts. Synthetic genes are increasingly used for protein production because sequence information is easier to obtain than the corresponding physical DNA. Protein-coding sequences are commonly re-designed to enhance expression, but there are no experimentally supported design principles. PRINCIPAL FINDINGS To identify sequence features that affect protein expression we synthesized and expressed in E. coli two sets of 40 genes encoding two commercially valuable proteins, a DNA polymerase and a single chain antibody. Genes differing only in synonymous codon usage expressed protein at levels ranging from undetectable to 30% of cellular protein. Using partial least squares regression we tested the correlation of protein production levels with parameters that have been reported to affect expression. We found that the amount of protein produced in E. coli was strongly dependent on the codons used to encode a subset of amino acids. Favorable codons were predominantly those read by tRNAs that are most highly charged during amino acid starvation, not codons that are most abundant in highly expressed E. coli proteins. Finally we confirmed the validity of our models by designing, synthesizing and testing new genes using codon biases predicted to perform well. CONCLUSION The systematic analysis of gene design parameters shown in this study has allowed us to identify codon usage within a gene as a critical determinant of achievable protein expression levels in E. coli. We propose a biochemical basis for this, as well as design algorithms to ensure high protein production from synthetic genes. Replication of this methodology should allow similar design algorithms to be empirically derived for any expression system.
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Wu ZL, Qiao J, Zhang ZG, Guengerich FP, Liu Y, Pei XQ. Enhanced bacterial expression of several mammalian cytochrome P450s by codon optimization and chaperone coexpression. Biotechnol Lett 2009; 31:1589-93. [PMID: 19557307 DOI: 10.1007/s10529-009-0059-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 05/26/2009] [Accepted: 05/27/2009] [Indexed: 12/16/2022]
Abstract
To elucidate the effects of codon optimization and chaperone coexpression on the heterologous expression of mammalian cytochrome P450s (P450) in Escherichia coli, the expression of P450s 2B1, 2S1, 2U1, 2W1, and 27C1 were investigated. With codon optimization for N-terminus or the entire gene, the expression levels of P450 27C1, 2U1 and 2W1 increased 22-fold, 3.6-fold and 2.1-fold, respectively, while those for P450s 2B1 and 2S1 remained unchanged. With coexpression of E. coli molecular chaperones GroEL/ES, the expression level increased up to 14-fold for P450 27C1, and 3- to 5-fold for P450s 2B1, 2S1, and 2W1. Simultaneous application of these two techniques resulted in synergetic effects.
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Affiliation(s)
- Zhong-Liu Wu
- Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, 610041, Chengdu, China.
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35
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Seshadri A, Dubey B, Weber MHW, Varshney U. Impact of rRNA methylations on ribosome recycling and fidelity of initiation inEscherichia coli. Mol Microbiol 2009; 72:795-808. [DOI: 10.1111/j.1365-2958.2009.06685.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kudla G, Murray AW, Tollervey D, Plotkin JB. Coding-sequence determinants of gene expression in Escherichia coli. Science 2009; 324:255-8. [PMID: 19359587 DOI: 10.1126/science.1170160] [Citation(s) in RCA: 1031] [Impact Index Per Article: 68.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Synonymous mutations do not alter the encoded protein, but they can influence gene expression. To investigate how, we engineered a synthetic library of 154 genes that varied randomly at synonymous sites, but all encoded the same green fluorescent protein (GFP). When expressed in Escherichia coli, GFP protein levels varied 250-fold across the library. GFP messenger RNA (mRNA) levels, mRNA degradation patterns, and bacterial growth rates also varied, but codon bias did not correlate with gene expression. Rather, the stability of mRNA folding near the ribosomal binding site explained more than half the variation in protein levels. In our analysis, mRNA folding and associated rates of translation initiation play a predominant role in shaping expression levels of individual genes, whereas codon bias influences global translation efficiency and cellular fitness.
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Affiliation(s)
- Grzegorz Kudla
- Department of Biology and Program in Applied Mathematics and Computational Science, University of Pennsylvania, Philadelphia, PA 19104, USA
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37
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Zalucki YM, Beacham IR, Jennings MP. Biased codon usage in signal peptides: a role in protein export. Trends Microbiol 2009; 17:146-50. [PMID: 19307122 DOI: 10.1016/j.tim.2009.01.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 12/03/2008] [Accepted: 01/14/2009] [Indexed: 10/21/2022]
Abstract
The signal peptide of proteins exported via the general secretory pathway encodes structural features that enable the targeting and export of the protein to the periplasm. Recent studies have shown biased codon usage at the second amino acid position and a high usage of non-optimal codons within the signal peptide. Altering these biases in codon usage can have deleterious effects on protein folding and export. We propose that these codon-usage biases act in concert to optimize the export process through modulating ribosome spacing on the transcript. This highlights a new aspect of protein export and implies that codon usage in the signal peptide encodes signals that are important for protein targeting and export to the periplasm.
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Affiliation(s)
- Yaramah M Zalucki
- School of Molecular and Microbial Sciences, University of Queensland, St. Lucia 4072, Brisbane, QLD, Australia
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38
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Welch M, Villalobos A, Gustafsson C, Minshull J. You're one in a googol: optimizing genes for protein expression. J R Soc Interface 2009; 6 Suppl 4:S467-76. [PMID: 19324676 DOI: 10.1098/rsif.2008.0520.focus] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A vast number of different nucleic acid sequences can all be translated by the genetic code into the same amino acid sequence. These sequences are not all equally useful however; the exact sequence chosen can have profound effects on the expression of the encoded protein. Despite the importance of protein-coding sequences, there has been little systematic study to identify parameters that affect expression. This is probably because protein expression has largely been tackled on an ad hoc basis in many independent projects: once a sequence has been obtained that yields adequate expression for that project, there is little incentive to continue work on the problem. Synthetic biology may now provide the impetus to transform protein expression folklore into design principles, so that DNA sequences may easily be designed to express any protein in any system. In this review, we offer a brief survey of the literature, outline the major challenges in interpreting existing data and constructing robust design algorithms, and propose a way to proceed towards the goal of rational sequence engineering.
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Affiliation(s)
- Mark Welch
- DNA 2.0, Inc., 1430 O'Brien Drive, Menlo Park, CA 94025, USA
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Thangadurai C, Suthakaran P, Barfal P, Anandaraj B, Pradhan SN, Ramalingam S, Murugan V. Rare codon priority and its position specificity at the 5' of the gene modulates heterologous protein expression in Escherichia coli. Biochem Biophys Res Commun 2008; 376:647-52. [PMID: 18801340 DOI: 10.1016/j.bbrc.2008.09.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Accepted: 09/05/2008] [Indexed: 11/20/2022]
Abstract
Rare codons and their effects in heterologous protein expression in Escherichia coli were addressed by many investigators. Here, we propose that not all rare codons of a foreign gene have negative effect but selective codon among them and its specific position in the downstream of the start codon modulates the expression. In our study, streptokinase (47 kDa), encoded by skc gene of Streptococcus equisimilis was expressed in E.coli. The analysis of relative codon frequency of skc gene in E.coli reveals the presence of 30% of rare codons in it. Nevertheless, E.coli managed to yield over-expression of this target protein. To explore the codon bias in expression, we have introduced the selective AGG codon at different positions of skc gene such as +2,+3,+5,+8,+9 and +11. The results revealed that at +2 position "AGG" aided over-expression while shifting to +3 and +5 positions it rendered nil expression. In contrary, shifting of AGG codon to later positions like +9 and +11 the inhibitory effect was reversed and resulted in over-expression. The effect of 'AGG' rare codon was further studied in GFP expression. In conclusion, besides the choice of rare codons, their precise positions in the foreign gene dictate the level of protein expression.
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Affiliation(s)
- Chinnathambi Thangadurai
- Genetic Engineering Unit, Centre for Biotechnology, Sadar Patel Road, Anna University, Guindy, Chennai-600 025, India
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40
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Pai VR, Murugan V. A synergistic effect of suppressive CGG codon in +2 position and downstream CAT repeats for efficient heterologous protein expression in Escherichia coli. Biochem Biophys Res Commun 2008; 371:380-384. [PMID: 18440305 DOI: 10.1016/j.bbrc.2008.04.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2008] [Accepted: 04/14/2008] [Indexed: 05/26/2023]
Abstract
The negative effect of NGG codons at +2 position has been well documented for the down regulation of recombinant protein expression in Escherichia coli. But this is not true when certain specific sequences are present in the downstream of NGG codons. This has been proved in our study while expressing human Erythropoietin (EPO) in E. coli GJ1158. Towards this, nine recombinant constructs were made and their expression profile was compared. In our results, we found that the suppressive nature of NGG codon (GGG, CGG) in the +2 position was overcome by imposing a downstream CAT repeat motif. The expression of EPO levels is higher in the constructs having the combination of both CGG codon at 2nd position and CAT repeats than the other constructs having either CGG or CAT repeat alone. In addition, it is also interesting to note that increasing number of CAT repeats shows increased expression levels.
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Affiliation(s)
- Vaishnavo Rabindranath Pai
- Genetic Engineering Unit, Centre for Biotechnology, Anna University, Sardar Patel Road, Guindy, Chennai 600 025, India
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41
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Jacinto-Loeza E, Vivanco-Domínguez S, Guarneros G, Hernández-Sánchez J. Minigene-like inhibition of protein synthesis mediated by hungry codons near the start codon. Nucleic Acids Res 2008; 36:4233-41. [PMID: 18583364 PMCID: PMC2490762 DOI: 10.1093/nar/gkn395] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rare AGA or AGG codons close to the initiation codon inhibit protein synthesis by a tRNA-sequestering mechanism as toxic minigenes do. To further understand this mechanism, a parallel analysis of protein synthesis and peptidyl-tRNA accumulation was performed using both a set of lacZ constructs where AGAAGA codons were moved codon by codon from +2, +3 up to +7, +8 positions and a series of 3–8 codon minigenes containing AGAAGA codons before the stop codon. β-Galactosidase synthesis from the AGAAGA lacZ constructs (in a Pth defective in vitro system without exogenous tRNA) diminished as the AGAAGA codons were closer to AUG codon. Likewise, β-galactosidase expression from the reporter +7 AGA lacZ gene (plus tRNA, 0.25 μg/μl) waned as the AGAAGAUAA minigene shortened. Pth counteracted both the length-dependent minigene effect on the expression of β-galactosidase from the +7 AGA lacZ reporter gene and the positional effect from the AGAAGA lacZ constructs. The +2, +3 AGAAGA lacZ construct and the shortest +2, +3 AGAAGAUAA minigene accumulated the highest percentage of peptidyl-tRNAArg4. These observations lead us to propose that hungry codons at early positions, albeit with less strength, inhibit protein synthesis by a minigene-like mechanism involving accumulation of peptidyl-tRNA.
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Affiliation(s)
- Eva Jacinto-Loeza
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México DF, 07000, México
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42
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Ahn JH, Keum JW, Kim DM. High-Throughput, Combinatorial Engineering of Initial Codons for Tunable Expression of Recombinant Proteins. J Proteome Res 2008; 7:2107-13. [DOI: 10.1021/pr700856s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jin-Ho Ahn
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Korea, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea, and Department of Fine Chemical Engineering and Chemistry, Chungnam National University, Daejeon 305-764, Korea
| | - Jung-Won Keum
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Korea, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea, and Department of Fine Chemical Engineering and Chemistry, Chungnam National University, Daejeon 305-764, Korea
| | - Dong-Myung Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Korea, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea, and Department of Fine Chemical Engineering and Chemistry, Chungnam National University, Daejeon 305-764, Korea
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43
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Byun JY, Kim DM. An In Vitro strategy for the rapid expression of recombinant proteins at low temperatures. BIOTECHNOL BIOPROC E 2008. [DOI: 10.1007/s12257-007-0178-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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44
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Kim KH, Yang JK, Waldo GS, Terwilliger TC, Suh SW. From no expression to high-level soluble expression in Escherichia coli by screening a library of the target proteins with randomized N-termini. Methods Mol Biol 2008; 426:187-195. [PMID: 18542864 DOI: 10.1007/978-1-60327-058-8_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
For structural studies by x-ray crystallography and nuclear magnetic resonance it is important for the target protein to be available in large quantity and high purity. Escherichia coli expression systems remain the most versatile and convenient means to produce a large quantity of recombinant proteins. Unfortunately, some proteins fail to be expressed in E. coli or are expressed in an insoluble form. To overcome the difficulty of no expression or expression at a very low level, a simple and efficient approach of screening a library of variants of a target protein with randomized N-termini was devised. In this method, a few N-terminal residues are randomized by designing a mixture of oligonucleotides for the forward PCR primer and we fuse the library in front of green fluorescent protein, which serves as a reporter for the target protein expression level and folding yield. In favorable cases this approach can result in high-level soluble expression of recombinant proteins in E. coli. This chapter describes the results of a test of this approach with a bacterial protein (the HI0952 gene product) that is not well expressed in E. coli.
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Affiliation(s)
- Kyoung Hoon Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, Korea
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45
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Nagase T, Nishio S, Itoh T. Essential elements in the coding region of mRNA for translation of ColE2 Rep protein. Plasmid 2007; 59:36-44. [PMID: 18061669 DOI: 10.1016/j.plasmid.2007.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 07/23/2007] [Accepted: 07/24/2007] [Indexed: 10/22/2022]
Abstract
Translation initiation of mRNA encoding the plasmid-specified initiator protein (Rep) required for initiation of the ColE2 plasmid DNA replication is fairly efficient in Escherichia coli despite the absence of a canonical Shine-Dalgarno sequence. Although a GA cluster sequence exists upstream the initiation codon, its activity as the SD sequence has been shown to be very inefficient. Deletion analyses have shown that there are sequences important for the Rep translation in the regions upstream the GA cluster sequence and downstream the initiation codon. To further define regions important for translation of the Rep mRNA, a set of the ColE2 rep genes bearing single-base substitution mutations in the coding region near the initiation codon was generated and their translation activities examined. We showed that translation of the Rep mRNA was reduced by some of these mutations in a region ranging at least 70 nucleotides from the initiation codon in the coding region, indicating the presence of translation enhancer(s) outside the translation initiation region which is covered by the ribosome bound to the initiation codon. Some of them seem to be essential and specific for translation of the ColE2 Rep mRNA due to the absence of a canonical SD sequence.
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Affiliation(s)
- T Nagase
- Department of Biology, Faculty of Science, Shinshu University, Matsumoto, Nagano 390-8621, Japan
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46
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Schwarz D, Junge F, Durst F, Frölich N, Schneider B, Reckel S, Sobhanifar S, Dötsch V, Bernhard F. Preparative scale expression of membrane proteins in Escherichia coli-based continuous exchange cell-free systems. Nat Protoc 2007; 2:2945-57. [PMID: 18007631 DOI: 10.1038/nprot.2007.426] [Citation(s) in RCA: 210] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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47
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Transient erythromycin resistance phenotype associated with peptidyl-tRNA drop-off on early UGG and GGG codons. J Bacteriol 2007; 189:8993-9000. [PMID: 17951392 DOI: 10.1128/jb.01004-07] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of minigenes encoding tetra- or pentapeptides MXLX or MXLXV (E peptides), where X is a nonpolar amino acid, renders cells erythromycin resistant whereas expression of minigenes encoding tripeptide MXL does not. By using a 3A' reporter gene system beginning with an E-peptide-encoding sequence, we asked whether the codons UGG and GGG, which are known to promote peptidyl-tRNA drop-off at early positions in mRNA, would result in a phenotype of erythromycin resistance if located after this sequence. We find that UGG or GGG, at either position +4 or +5, without a following stop codon, is associated with an erythromycin resistance phenotype upon gene induction. Our results suggest that, while a stop codon at +4 gives a tripeptide product (MIL) and erythromycin sensitivity, UGG or GGG codons at the same position give a tetrapeptide product (MILW or MILG) and phenotype of erythromycin resistance. Thus, the drop-off event on GGG or UGG codons occurs after incorporation of the corresponding amino acid into the growing peptide chain. Drop-off gives rise to a peptidyl-tRNA where the peptide moiety functionally mimics a minigene peptide product of the type previously associated with erythromycin resistance. Several genes in Escherichia coli fulfill the requirements of high mRNA expression and an E-peptide sequence followed by UGG or GGG at position +4 or +5 and should potentially be able to give an erythromycin resistance phenotype.
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Buchan JR, Stansfield I. Halting a cellular production line: responses to ribosomal pausing during translation. Biol Cell 2007; 99:475-87. [PMID: 17696878 DOI: 10.1042/bc20070037] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cellular protein synthesis is a complex polymerization process carried out by multiple ribosomes translating individual mRNAs. The process must be responsive to rapidly changing conditions in the cell that could cause ribosomal pausing and queuing. In some circumstances, pausing of a bacterial ribosome can trigger translational abandonment via the process of trans-translation, mediated by tmRNA (transfer-messenger RNA) and endonucleases. Together, these factors release the ribosome from the mRNA and target the incomplete polypeptide for destruction. In eukaryotes, ribosomal pausing can initiate an analogous process carried out by the Dom34p and Hbs1p proteins, which trigger endonucleolytic attack of the mRNA, a process termed mRNA no-go decay. However, ribosomal pausing can also be employed for regulatory purposes, and controlled translational delays are used to help co-translational folding of the nascent polypeptide on the ribosome, as well as a tactic to delay translation of a protein while its encoding mRNA is being localized within the cell. However, other responses to pausing trigger ribosomal frameshift events. Recent discoveries are thus revealing a wide variety of mechanisms used to respond to translational pausing and thus regulate the flow of ribosomal traffic on the mRNA population.
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Affiliation(s)
- J Ross Buchan
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, Scotland, UK
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49
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Zamora-Romo E, Cruz-Vera LR, Vivanco-Domínguez S, Magos-Castro MA, Guarneros G. Efficient expression of gene variants that harbour AGA codons next to the initiation codon. Nucleic Acids Res 2007; 35:5966-74. [PMID: 17726048 PMCID: PMC2034473 DOI: 10.1093/nar/gkm643] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In an effort to improve the knowledge about the rules which direct the effect of the early ORF sequences on translation efficiency, we have analyzed the effect of pairs of the six arginine codons at the second and third positions on the expression of lacZ variants. Whereas the pairs of identical AGA or AGG codons were favorable for the gene expression, identical pairs of each of the four CGN codons were very inefficient. This result was unexpected because tandems of AGA or AGG codons located in more internal gene positions provoke deficient expression whilst internally located CGU and CGC are the most abundant and efficiently translated arginine codons. The mixed combinations of AGA and each of the CGN codons usually resulted in efficient rates of lacZ expression independently of the peptidyl-tRNA propensity to dissociate from the ribosome. Thus, the variant harboring the pair of AGA codons was expressed as efficiently as the variant carrying a pair of AAA codons in the same positions, a configuration reported as one of the most common and efficient for gene expression. We explain these results assuming that the presence of adenines in these early positions enhance gene expression. As expected, specific mRNA levels correlated with the intensity of lacZ expression for each variant. However, the induction of lacZ AGA AGA gene in pth cells accumulated peptidyl-tRNAArg4 as well as a short 5′-proximal lacZ mRNA fragment suggesting ribosome stalling due to depletion of aminoacylated-tRNAArg4.
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Affiliation(s)
- Efraín Zamora-Romo
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 México D. F. and Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA
| | - Luis Rogelio Cruz-Vera
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 México D. F. and Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA
| | - Serafín Vivanco-Domínguez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 México D. F. and Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA
| | - Marco Antonio Magos-Castro
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 México D. F. and Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA
| | - Gabriel Guarneros
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 México D. F. and Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA
- *To whom correspondence should be addressed. +52 55 5061 3338+52 55 5061 3392
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Abstract
In Escherichia coli and Salmonella enterica, activation of sigma(E)-dependent envelope stress response leads to the abrupt decline in the synthesis of all major outer membrane proteins (OMPs). Recent studies found that two sigma(E)-controlled small RNAs (sRNAs), MicA and RybB, downregulate a number of OMPs. While RybB targets several different mRNAs, including ompC and ompD, MicA was up to date thought to act solely on ompA. Here we present evidence showing that MicA downregulates a second Salmonella OMP: LamB maltoporine. In strains overexpressing sigma(E), MicA accumulation leads to a significant decrease in LamB protein and mRNA levels, as well as a reduction in beta-galactosidase activity in a strain carrying a lamB-lacZ translational fusion. The latter findings provided the basis for a genetic screen that allowed isolating point mutations in the micA gene and in its sigma(E) promoter. All alleles obtained displayed their altered regulatory phenotype from their natural chromosomal location. LamB downregulation by MicA requires a functional Hfq protein. Besides this role, confined to sigma(E)-activated conditions, we show that loss of Hfq results in the accumulation of a lamB-malM dimeric precursor and of malM mRNA during unchallenged growth. This suggests that Hfq normally intervenes in a mechanism that uncouples expression of the malK-lamB-malM operon, causing the distal portion of the transcript to be clipped off and degraded.
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Affiliation(s)
- Lionello Bossi
- Centre de Génétique Moléculaire, CNRS, 91198, Gif-sur-Yvette, France.
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