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İncir İ, Kaplan Ö. Escherichia coli as a versatile cell factory: Advances and challenges in recombinant protein production. Protein Expr Purif 2024; 219:106463. [PMID: 38479588 DOI: 10.1016/j.pep.2024.106463] [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] [Received: 01/03/2024] [Revised: 02/25/2024] [Accepted: 03/11/2024] [Indexed: 05/08/2024]
Abstract
E. coli plays a substantial role in recombinant protein production. Its importance increased with the discovery of recombinant DNA technology and the subsequent production of the first recombinant insulin in E. coli. E. coli is a widely used and cost-effective host to produce recombinant proteins. It is also noteworthy that a significant portion of the approved therapeutic proteins have been produced in this organism. Despite these advantages, it has some disadvantages, such as toxicity and lack of eukaryotic post-translational modifications that can lead to the production of misfolded, insoluble, or dysfunctional proteins. This study focused on the challenges and engineering approaches for improved expression and solubility in recombinant protein production in E. coli. In this context, solution strategies such as strain and vector selection, codon usage, mRNA stability, expression conditions, translocation to the periplasmic region and addition of fusion tags in E. coli were discussed.
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Affiliation(s)
- İbrahim İncir
- Karamanoğlu Mehmetbey University, Kazım Karabekir Vocational School, Department of Medical Services and Techniques, Environmental Health Program Karaman, Turkey.
| | - Özlem Kaplan
- Alanya Alaaddin Keykubat University, Rafet Kayış Faculty of Engineering, Department of Genetics and Bioengineering, Antalya, Turkey.
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2
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Zhu YJ, Liao ML, Dong YW. Exploring the adaptability of the secondary structure of mRNA to temperature in intertidal snails based on SHAPE experiments. J Exp Biol 2023; 226:jeb246544. [PMID: 37767692 DOI: 10.1242/jeb.246544] [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] [Received: 08/16/2023] [Accepted: 09/22/2023] [Indexed: 09/29/2023]
Abstract
RNA-based thermal regulation is an important strategy for organisms to cope with temperature changes. Inhabiting the intertidal rocky shore, a key interface of the ocean, atmosphere and terrestrial environments, intertidal species have developed variable thermal adaptation mechanisms; however, adaptions at the RNA level remain largely uninvestigated. To examine the relationship between mRNA structural stability and species distribution, in the present study, the secondary structure of cytosolic malate dehydrogenase (cMDH) mRNA of Echinolittorina malaccana, Echinolittorina radiata and Littorina brevicula was determined using selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE), and the change in folding free energy of formation (ΔGfold) was calculated. The results showed that ΔGfold increased as the temperature increased. The difference in ΔGfold (ΔΔGfold) between two specific temperatures (25 versus 0°C, 37 versus 0°C and 57 versus 0°C) differed among the three species, and the ΔΔGfold value of E. malaccana was significantly lower than those of E. radiata and L. brevicula. The number of stems of cMDH mRNA of the snails decreased with increasing temperature, and the breakpoint temperature of E. malaccana was the highest among these. The number of loops was also reduced with increasing temperature, while the length of the loop structure increased accordingly. Consequently, these structural changes can potentially affect the translational efficiency of mRNA. These results imply that there were interspecific differences in the thermal stability of RNA secondary structures in intertidal snails, and these differences may be related to snail distribution.
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Affiliation(s)
- Ya-Jie Zhu
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao 266003, PR China
| | - Ming-Ling Liao
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao 266003, PR China
| | - Yun-Wei Dong
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao 266003, PR China
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3
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Li X, Ding N, Zhang Z, Tian D, Han B, Liu D, Liu S, Tian F, Fu D, Song X, Zhao K. Identification of SSTR5 Gene Polymorphisms and Their Association With Growth Traits in Hulun Buir Sheep. Front Genet 2022; 13:831599. [PMID: 35559027 PMCID: PMC9086292 DOI: 10.3389/fgene.2022.831599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/10/2022] [Indexed: 11/15/2022] Open
Abstract
The aim of this study was to locate SSTR5 polymorphisms and evaluate their association with growth traits in Hulun Buir sheep. The study followed up 884 Hulun Buir sheep from birth to 16 months of age, which were born in the same pasture and the same year, and a consistent grazing management strategy was maintained. The birth weight (BRW) was recorded at birth, and body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured at 4 and 9 months of age. BW, BH, BL, ChD, HW, and CaC were also recorded at 16 months of age. Based on the growth traits, 233 sheep were selected as experimental animals. Sanger sequencing was performed, and seven single-nucleotide polymorphisms (SNPs) were identified. Association analyses of the SNPs and the growth traits were then conducted. Seven SNPs of the SSTR5 exhibited moderate polymorphism (0.25
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Affiliation(s)
- Xue Li
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ning Ding
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhichao Zhang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dehong Tian
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Buying Han
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dehui Liu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Sijia Liu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Fei Tian
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Dejun Fu
- Inner Mongolia Daxing 'anling Agricultural Reclamation Group Co. LTD., Hulun Buir, China
| | - Xiaoliang Song
- Inner Mongolia Daxing 'anling Agricultural Reclamation Group Co. LTD., Hulun Buir, China
| | - Kai Zhao
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Qinghai Provincial Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
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Genetic Polymorphisms of IGF1 and IGF1R Genes and Their Effects on Growth Traits in Hulun Buir Sheep. Genes (Basel) 2022; 13:genes13040666. [PMID: 35456472 PMCID: PMC9031115 DOI: 10.3390/genes13040666] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/25/2022] [Accepted: 04/07/2022] [Indexed: 01/08/2023] Open
Abstract
The identification of candidate genes and genetic variations associated with growth traits is important for sheep breeding. Insulin like growth factor 1 (IGF1) and insulin like growth factor 1 receptor (IGF1R) are well-accepted candidate genes that affect animal growth and development. The current study attempted to assess the association between IGF1 and IGF1R genetic polymorphisms and growth traits in Hulun Buir sheep. To achieve this goal, we first identified three and ten single nucleotide polymorphisms (SNPs) in exons of IGF1 and IGF1R in Hulun Buir sheep and then constructed six haplotypes of IGF1R based on linkage disequilibrium, respectively. Association studies were performed between SNPs and haplotypes of IGF1 and IGF1R with twelve growth traits in a population encompassing 229 Hulun Buir sheep using a general linear model. Our result indicated three SNPs in IGF1 were significantly associated with four growth traits (p < 0.05). In IGF1R, three SNPs and two haplotype blocks were significantly associated with twelve growth traits (p < 0.05). The combined haplotype H5H5 and H5H6 in IGF1R showed the strong association with 12 superior growth traits in Hulun Buir sheep (p < 0.05). In conclusion, we identified SNPs and haplotype combinations associated with the growth traits, which provided genetic resources for marker-assisted selection (MAS) in Hulun Buir sheep breeding.
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Identification of Somatostatin Receptor Subtype 1 (SSTR1) Gene Polymorphism and Their Association with Growth Traits in Hulun Buir Sheep. Genes (Basel) 2021; 13:genes13010077. [PMID: 35052417 PMCID: PMC8775034 DOI: 10.3390/genes13010077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/19/2022] Open
Abstract
This study was conducted to evaluate SSTR1 gene polymorphisms and their association with growth traits in Hulun Buir sheep. We followed 233 Hulun Buir sheep from birth to 16 months of age, born in the same pasture and on the same year under a consistent grazing conditions. The body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured and recorded at birth, 4 months, 9 months, and 16 months of age. The polymorphisms of the SSTR1 gene in Hulun Buir sheep were excavated using exon sequencing, and association analyses of between SNPs and growth traits at each growth stage were conducted. The results showed that there were four SNPs in Exon 2 of the SSTR1 gene, SNP1, SNP2, and SNP3 were low mutation sites, and SNP4 was a moderate mutation site. Four SNPs were consistent with Hardy–Weinberg equilibrium, and all of them were synonymous mutations. The association analyses found that the genotypes of SNP2 were significantly associated with WW and BH at 4 months of age, BW, BL, ChC, and HW at 9 months of age (p < 0.05), and extremely significantly associated with ChD at 4 and 9 months of age (p < 0.01). There were significant associations between SNP3 and BH at 9 months of age, between SNP4 and ChD, ChW, and CaC at 9 months of age, and BW and ChC at 16 months of age (p < 0.05). There were no detectable associations with growth traits among the seven haplotypes between the SNP1, 3, and 4 of a strong linkage disequilibrium (p > 0.05). These results indicated that SNP2, SNP3, and SNP4 may be used as molecular markers for growth traits of Hulun Buir sheep.
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Qi T, Xu Y, Zhou T, Gu W. The Evolution of G-quadruplex Structure in mRNA Untranslated Region. Evol Bioinform Online 2021; 17:11769343211035140. [PMID: 34366661 DOI: 10.1177/11769343211035140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/06/2021] [Indexed: 01/22/2023] Open
Abstract
The RNA G-quadruplex (rG4) is a kind of non-canonical high-order secondary structure with important biological functions and is enriched in untranslated regions (UTRs) of protein-coding genes. However, how rG4 structures evolve is largely unknown. Here, we systematically investigated the evolution of RNA sequences around UTR rG4 structures in 5 eukaryotic organisms. We found universal selection on UTR sequences, which facilitated rG4 formation in all the organisms that we analyzed. While G-rich sequences were preferred in the rG4 structural region, C-rich sequences were selectively not preferred. The selective pressure acting on rG4 structures in the UTRs of genes with higher G content was significantly smaller. Furthermore, we found that rG4 structures experienced smaller evolutionary selection near the translation initiation region in the 5' UTR, near the polyadenylation signals in the 3' UTR, and in regions flanking the miRNA targets in the 3' UTR. These results suggest universal selection for rG4 formation in the UTRs of eukaryotic genomes and the selection may be related to the biological functions of rG4s.
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Affiliation(s)
- Ting Qi
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Yuming Xu
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Wanjun Gu
- State Key Laboratory of Bioelectronics, School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China.,Collaborative Innovation Center of Jiangsu Province of Cancer Prevention and Treatment of Chinese Medicine, Nanjing, Jiangsu, China.,School of Artificial Intelligence and Information Technology, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
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Gaither JBS, Lammi GE, Li JL, Gordon DM, Kuck HC, Kelly BJ, Fitch JR, White P. Synonymous variants that disrupt messenger RNA structure are significantly constrained in the human population. Gigascience 2021; 10:6211353. [PMID: 33822938 PMCID: PMC8023685 DOI: 10.1093/gigascience/giab023] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 02/10/2021] [Accepted: 03/10/2021] [Indexed: 12/16/2022] Open
Abstract
Background The role of synonymous single-nucleotide variants in human health and disease is poorly understood, yet evidence suggests that this class of “silent” genetic variation plays multiple regulatory roles in both transcription and translation. One mechanism by which synonymous codons direct and modulate the translational process is through alteration of the elaborate structure formed by single-stranded mRNA molecules. While tools to computationally predict the effect of non-synonymous variants on protein structure are plentiful, analogous tools to systematically assess how synonymous variants might disrupt mRNA structure are lacking. Results We developed novel software using a parallel processing framework for large-scale generation of secondary RNA structures and folding statistics for the transcriptome of any species. Focusing our analysis on the human transcriptome, we calculated 5 billion RNA-folding statistics for 469 million single-nucleotide variants in 45,800 transcripts. By considering the impact of all possible synonymous variants globally, we discover that synonymous variants predicted to disrupt mRNA structure have significantly lower rates of incidence in the human population. Conclusions These findings support the hypothesis that synonymous variants may play a role in genetic disorders due to their effects on mRNA structure. To evaluate the potential pathogenic impact of synonymous variants, we provide RNA stability, edge distance, and diversity metrics for every nucleotide in the human transcriptome and introduce a “Structural Predictivity Index” (SPI) to quantify structural constraint operating on any synonymous variant. Because no single RNA-folding metric can capture the diversity of mechanisms by which a variant could alter secondary mRNA structure, we generated a SUmmarized RNA Folding (SURF) metric to provide a single measurement to predict the impact of secondary structure altering variants in human genetic studies.
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Affiliation(s)
- Jeffrey B S Gaither
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Grant E Lammi
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - James L Li
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - David M Gordon
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Harkness C Kuck
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Benjamin J Kelly
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - James R Fitch
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA
| | - Peter White
- Computational Genomics Group, The Institute for Genomic Medicine, Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH 43215, USA.,Department of Pediatrics, College of Medicine, The Ohio State University, 370 W. 9th Avenue, Columbus, OH 43210, USA
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Hia F, Takeuchi O. The effects of codon bias and optimality on mRNA and protein regulation. Cell Mol Life Sci 2021; 78:1909-1928. [PMID: 33128106 PMCID: PMC11072601 DOI: 10.1007/s00018-020-03685-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/05/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022]
Abstract
The central dogma of molecular biology entails that genetic information is transferred from nucleic acid to proteins. Notwithstanding retro-transcribing genetic elements, DNA is transcribed to RNA which in turn is translated into proteins. Recent advancements have shown that each stage is regulated to control protein abundances for a variety of essential physiological processes. In this regard, mRNA regulation is essential in fine-tuning or calibrating protein abundances. In this review, we would like to discuss one of several mRNA-intrinsic features of mRNA regulation that has been gaining traction of recent-codon bias and optimality. Specifically, we address the effects of codon bias with regard to codon optimality in several biological processes centred on translation, such as mRNA stability and protein folding among others. Finally, we examine how different organisms or cell types, through this system, are able to coordinate physiological pathways to respond to a variety of stress or growth conditions.
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Affiliation(s)
- Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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Peeri M, Tuller T. High-resolution modeling of the selection on local mRNA folding strength in coding sequences across the tree of life. Genome Biol 2020; 21:63. [PMID: 32151272 PMCID: PMC7063772 DOI: 10.1186/s13059-020-01971-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 02/22/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND mRNA can form local secondary structure within the protein-coding sequence, and the strength of this structure is thought to influence gene expression regulation. Previous studies suggest that secondary structure strength may be maintained under selection, but the details of this phenomenon are not well understood. RESULTS We perform a comprehensive study of the selection on local mRNA folding strengths considering variation between species across the tree of life. We show for the first time that local folding strength selection tends to follow a conserved characteristic profile in most phyla, with selection for weak folding at the two ends of the coding region and for strong folding elsewhere in the coding sequence, with an additional peak of selection for strong folding located downstream of the start codon. The strength of this pattern varies between species and organism groups, and we highlight contradicting cases. To better understand the underlying evolutionary process, we show that selection strengths in the different regions are strongly correlated, and report four factors which have a clear predictive effect on local mRNA folding selection within the coding sequence in different species. CONCLUSIONS The correlations observed between selection for local secondary structure strength in the different regions and with the four genomic and environmental factors suggest that they are shaped by the same evolutionary process throughout the coding sequence, and might be maintained under direct selection related to optimization of gene expression and specifically translation regulation.
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Affiliation(s)
- Michael Peeri
- Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel.
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.
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Nucleotide composition affects codon usage toward the 3'-end. PLoS One 2019; 14:e0225633. [PMID: 31800603 PMCID: PMC6892556 DOI: 10.1371/journal.pone.0225633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 11/09/2019] [Indexed: 12/24/2022] Open
Abstract
The 3’-end of the coding sequence in several species is known to show specific codon usage bias. Several factors have been suggested to underlie this phenomenon, including selection against translation efficiency, selection for translation accuracy, and selection against RNA folding. All are supported by some evidence, but there is no general agreement as to which factors are the main determinants. Nor is it known how universal this phenomenon is, and whether the same factors explain it in different species. To answer these questions, we developed a measure that quantifies the codon usage bias at the gene end, and used it to compute this bias for 91 species that span the three domains of life. In addition, we characterized the codons in each species by features that allow discrimination between the different factors. Combining all these data, we were able to show that there is a universal trend to favor AT-rich codons toward the gene end. Moreover, we suggest that this trend is explained by avoidance from forming RNA secondary structures around the stop codon, which may interfere with normal translation termination.
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Chiok KLR, Shah DH. Identification of common highly expressed genes of Salmonella Enteritidis by in silico prediction of gene expression and in vitro transcriptomic analysis. Poult Sci 2019; 98:2948-2963. [PMID: 30953073 DOI: 10.3382/ps/pez119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/27/2019] [Indexed: 01/02/2023] Open
Abstract
Chickens are the reservoir host of Salmonella Enteritidis. Salmonella Enteritidis colonizes the gastro-intestinal tract of chickens and replicates within macrophages without causing clinically discernable illness. Persistence of S. Enteritidis in the hostile environments of intestinal tract and macrophages allows it to disseminate extra-intestinally to liver, spleen, and reproductive tract. Extra-intestinal dissemination into reproductive tract leads to contamination of internal contents of eggs, which is a major risk factor for human infection. Understanding the genes that contribute to S. Enteritidis persistence in the chicken host is central to elucidate the genetic basis of the unique pathobiology of this public health pathogen. The aim of this study was to identify a succinct set of genes associated with infection-relevant in vitro environments to provide a rational foundation for subsequent biologically-relevant research. We used in silico prediction of gene expression and RNA-seq technology to identify a core set of 73 S. Enteritidis genes that are consistently highly expressed in multiple S. Enteritidis strains cultured at avian physiologic temperature under conditions that represent intestinal and intracellular environments. These common highly expressed (CHX) genes encode proteins involved in bacterial metabolism, protein synthesis, cell-envelope biogenesis, stress response, and a few proteins with uncharacterized functions. Further studies are needed to dissect the contribution of these CHX genes to the pathobiology of S. Enteritidis in the avian host. Several of the CHX genes could serve as promising targets for studies towards the development of immunoprophylactic and novel therapeutic strategies to prevent colonization of chickens and their environment with S. Enteritidis.
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Affiliation(s)
- Kim Lam R Chiok
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040
| | - Devendra H Shah
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040
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Horga LG, Halliwell S, Castiñeiras TS, Wyre C, Matos CFRO, Yovcheva DS, Kent R, Morra R, Williams SG, Smith DC, Dixon N. Tuning recombinant protein expression to match secretion capacity. Microb Cell Fact 2018; 17:199. [PMID: 30577801 PMCID: PMC6303999 DOI: 10.1186/s12934-018-1047-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/14/2018] [Indexed: 03/08/2023] Open
Abstract
Background The secretion of recombinant disulfide-bond containing proteins into the periplasm of Gram-negative bacterial hosts, such as E. coli, has many advantages that can facilitate product isolation, quality and activity. However, the secretion machinery of E. coli has a limited capacity and can become overloaded, leading to cytoplasmic retention of product; which can negatively impact cell viability and biomass accumulation. Fine control over recombinant gene expression offers the potential to avoid this overload by matching expression levels to the host secretion capacity. Results Here we report the application of the RiboTite gene expression control system to achieve this by finely controlling cellular expression levels. The level of control afforded by this system allows cell viability to be maintained, permitting production of high-quality, active product with enhanced volumetric titres. Conclusions The methods and systems reported expand the tools available for the production of disulfide-bond containing proteins, including antibody fragments, in bacterial hosts. Electronic supplementary material The online version of this article (10.1186/s12934-018-1047-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Luminita Gabriela Horga
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | - Samantha Halliwell
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | | | | | | | | | - Ross Kent
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | - Rosa Morra
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M1 7DN, UK
| | | | | | - Neil Dixon
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M1 7DN, UK.
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Kent R, Halliwell S, Young K, Swainston N, Dixon N. Rationalizing Context-Dependent Performance of Dynamic RNA Regulatory Devices. ACS Synth Biol 2018; 7:1660-1668. [PMID: 29928800 DOI: 10.1021/acssynbio.8b00041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The ability of RNA to sense, regulate, and store information is an attractive attribute for a variety of functional applications including the development of regulatory control devices for synthetic biology. RNA folding and function is known to be highly context sensitive, which limits the modularity and reuse of RNA regulatory devices to control different heterologous sequences and genes. We explored the cause and effect of sequence context sensitivity for translational ON riboswitches located in the 5' UTR, by constructing and screening a library of N-terminal synonymous codon variants. By altering the N-terminal codon usage we were able to obtain RNA devices with a broad range of functional performance properties (ON, OFF, fold-change). Linear regression and calculated metrics were used to rationalize the major determining features leading to optimal riboswitch performance, and to identify multiple interactions between the explanatory metrics. Finally, partial least squared (PLS) analysis was employed in order to understand the metrics and their respective effect on performance. This PLS model was shown to provide good explanation of our library. This study provides a novel multivariant analysis framework to rationalize the codon context performance of allosteric RNA-devices. The framework will also serve as a platform for future riboswitch context engineering endeavors.
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Affiliation(s)
- Ross Kent
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Samantha Halliwell
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Kate Young
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Neil Swainston
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Neil Dixon
- Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester, M13 9PL, United Kingdom
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14
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Hockenberry AJ, Stern AJ, Amaral LAN, Jewett MC. Diversity of Translation Initiation Mechanisms across Bacterial Species Is Driven by Environmental Conditions and Growth Demands. Mol Biol Evol 2017; 35:582-592. [PMID: 29220489 PMCID: PMC5850609 DOI: 10.1093/molbev/msx310] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The Shine-Dalgarno (SD) sequence motif is frequently found upstream of protein coding genes and is thought to be the dominant mechanism of translation initiation used by bacteria. Experimental studies have shown that the SD sequence facilitates start codon recognition and enhances translation initiation by directly interacting with the highly conserved anti-SD sequence on the 30S ribosomal subunit. However, the proportion of SD-led genes within a genome varies across species and the factors governing this variation in translation initiation mechanisms remain largely unknown. Here, we conduct a phylogenetically informed analysis and find that species capable of rapid growth contain a higher proportion of SD-led genes throughout their genomes. We show that SD sequence utilization covaries with a suite of genomic features that are important for efficient translation initiation and elongation. In addition to these endogenous genomic factors, we further show that exogenous environmental factors may influence the evolution of translation initiation mechanisms by finding that thermophilic species contain significantly more SD-led genes than mesophiles. Our results demonstrate that variation in translation initiation mechanisms across bacterial species is predictable and is a consequence of differential life-history strategies related to maximum growth rate and environmental-specific constraints.
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Affiliation(s)
- Adam J Hockenberry
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Interdisciplinary Program in Biological Sciences, Northwestern University, Evanston, IL, USA
| | - Aaron J Stern
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
| | - Luís A N Amaral
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Northwestern Institute for Complex Systems, Northwestern University, Evanston, IL, USA
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA
- Corresponding authors: E-mails: ;
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
- Northwestern Institute for Complex Systems, Northwestern University, Evanston, IL, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL, USA
- Corresponding authors: E-mails: ;
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15
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Behloul N, Wei W, Baha S, Liu Z, Wen J, Meng J. Effects of mRNA secondary structure on the expression of HEV ORF2 proteins in Escherichia coli. Microb Cell Fact 2017; 16:200. [PMID: 29137642 PMCID: PMC5686824 DOI: 10.1186/s12934-017-0812-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/06/2017] [Indexed: 12/21/2022] Open
Abstract
Background Viral protein expression in Escherichia coli (E. coli) is a powerful tool for structural/functional studies as well as for vaccine and diagnostics development. However, numerous factors such as codon bias, mRNA secondary structure and nucleotides distribution, have been indentified to hamper this heterologous expression. Results In this study, we combined computational and biochemical methods to analyze the influence of these factors on the expression of different segments of hepatitis E virus (HEV) ORF 2 protein and hepatitis B virus surface antigen (HBsAg). Three out of five HEV antigens were expressed while all three HBsAg fragments were not. The computational analysis revealed a significant difference in nucleotide distribution between expressed and non-expressed genes; and all these non-expressing constructs shared similar stable 5′-end mRNA secondary structures that affected the accessibility of both Shine-Dalgarno (SD) sequence and start codon AUG. By modifying the 5′-end of HEV and HBV non-expressed genes, there was a significant increase in the total free energy of the mRNA secondary structures that permitted the exposure of the SD sequence and the start codon, which in turn, led to the successful expression of these genes in E. coli. Conclusions This study demonstrates that the mRNA secondary structure near the start codon is the key limiting factor for an efficient expression of HEV ORF2 proteins in E. coli. It describes also a simple and effective strategy for the production of viral proteins of different lengths for immunogenicity/antigenicity comparative studies during vaccine and diagnostics development. Electronic supplementary material The online version of this article (10.1186/s12934-017-0812-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nouredine Behloul
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 DingJiaQiao Road, Nanjing, 210009, Jiangsu, China
| | - Wenjuan Wei
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 DingJiaQiao Road, Nanjing, 210009, Jiangsu, China
| | - Sarra Baha
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 DingJiaQiao Road, Nanjing, 210009, Jiangsu, China
| | - Zhenzhen Liu
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 DingJiaQiao Road, Nanjing, 210009, Jiangsu, China
| | - Jiyue Wen
- Department of Pharmacology, Anhui Medical University, Hefei, 230032, China
| | - Jihong Meng
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 DingJiaQiao Road, Nanjing, 210009, Jiangsu, China.
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16
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Abstract
MOTIVATION Ribosome profiling is a useful technique for studying translational dynamics and quantifying protein synthesis. Applications of this technique have shown that ribosomes are not uniformly distributed along mRNA transcripts. Understanding how each transcript-specific distribution arises is important for unraveling the translation mechanism. RESULTS Here, we apply kernel smoothing to construct predictive features and build a sparse model to predict the shape of ribosome footprint profiles from transcript sequences alone. Our results on Saccharomyces cerevisiae data show that the marginal ribosome densities can be predicted with high accuracy. The proposed novel method has a wide range of applications, including inferring isoform-specific ribosome footprints, designing transcripts with fast translation speeds and discovering unknown modulation during translation. AVAILABILITY AND IMPLEMENTATION A software package called riboShape is freely available at https://sourceforge.net/projects/riboshape CONTACT yss@berkeley.edu.
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Affiliation(s)
- Tzu-Yu Liu
- Department of Mathematics and Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA Department of Electrical Engineering and Computer Sciences
| | - Yun S Song
- Department of Mathematics and Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA Department of Electrical Engineering and Computer Sciences Department of Statistics and Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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17
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Bhattacharya S, Reddy D, Reddy R, Sharda A, Bose K, Gupta S. Incorporation of a tag helps to overcome expression variability in a recombinant host. ACTA ACUST UNITED AC 2017; 11:62-69. [PMID: 28352541 PMCID: PMC5042304 DOI: 10.1016/j.btre.2016.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 06/08/2016] [Accepted: 06/27/2016] [Indexed: 11/03/2022]
Abstract
Reason for the lack of recombinant protein expression in E. coli is indefinite. Recombinant histone expression does not correlate with rare codon content. Translational variability may lead to lack of expression or degradation of protein. Expression variability could be averted by incorporating a tag.
Epigenetics have witnessed a renewed interest over the past decade and assays with recombinant histones has become an important tool for uncovering various aspects of histone biology. However, at times absence of recombinant histone accumulation in bacteria is encountered which is also commonly observed for many eukaryotic proteins in general. In this study, we have investigated the effect of multiple parameters on heterologous expression of proteins. We show that there is marked variability in the accumulation of H2A.2, H2B.1, H3.2 and H4 in the recombinant host, possibly owing to translational variability and degradation by the host proteases. We found that the variability could be overcome by incorporation of the commonly used purification tags, like GST or MBP, of appropriate size and position. Our results provide compelling evidence that transcript parameters like rare codon and GC content, mRNA secondary structure etc. together modulate translation kinetics and govern recombinant protein accumulation.
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Key Words
- CAI, codon adaptation indexes
- DUSP1, dual specificity phosphatase 1
- GAPDH, glyceraldehyde phosphate dehydrogenase
- GST, glutathione-S-transferase
- HAX-1, human protein HCLS-1 associated protein X-1
- Histones
- IPTG, Isopropyl β-d-1-thiogalactopyranoside
- MALDI, matrix-assisted laser desorption/ionization
- MBP, maltose binding protein
- Misfolding
- NAP1, nucleosome assemble protein 1
- PP1, protein phosphatase 1
- RBS, ribosome-binding site
- RT-PCR, reverse transcriptase polymerase chain reaction
- Rare codons
- TMAO, trimethylamine oxide
- Translation
- Truncated GST
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Affiliation(s)
| | - Divya Reddy
- Epigenetics and Chromatin Biology Group, Gupta Lab, India
| | - Raja Reddy
- Integrated Biophysics and Structural Biology Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Asmita Sharda
- Epigenetics and Chromatin Biology Group, Gupta Lab, India
| | - Kakoli Bose
- Integrated Biophysics and Structural Biology Lab, Cancer Research Institute, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai 410210, MH, India
| | - Sanjay Gupta
- Epigenetics and Chromatin Biology Group, Gupta Lab, India
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18
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Omotajo D, Tate T, Cho H, Choudhary M. Distribution and diversity of ribosome binding sites in prokaryotic genomes. BMC Genomics 2015; 16:604. [PMID: 26268350 PMCID: PMC4535381 DOI: 10.1186/s12864-015-1808-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 08/03/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Prokaryotic translation initiation involves the proper docking, anchoring, and accommodation of mRNA to the 30S ribosomal subunit. Three initiation factors (IF1, IF2, and IF3) and some ribosomal proteins mediate the assembly and activation of the translation initiation complex. Although the interaction between Shine-Dalgarno (SD) sequence and its complementary sequence in the 16S rRNA is important in initiation, some genes lacking an SD ribosome binding site (RBS) are still well expressed. The objective of this study is to examine the pattern of distribution and diversity of RBS in fully sequenced bacterial genomes. The following three hypotheses were tested: SD motifs are prevalent in bacterial genomes; all previously identified SD motifs are uniformly distributed across prokaryotes; and genes with specific cluster of orthologous gene (COG) functions differ in their use of SD motifs. RESULTS Data for 2,458 bacterial genomes, previously generated by Prodigal (PROkaryotic DYnamic programming Gene-finding ALgorithm) and currently available at the National Center for Biotechnology Information (NCBI), were analyzed. Of the total genes examined, ~77.0% use an SD RBS, while ~23.0% have no RBS. Majority of the genes with the most common SD motifs are distributed in a manner that is representative of their abundance for each COG functional category, while motifs 13 (5'-GGA-3'/5'-GAG-3'/5'-AGG-3') and 27 (5'-AGGAGG-3') appear to be predominantly used by genes for information storage and processing, and translation and ribosome biogenesis, respectively. CONCLUSION These findings suggest that an SD sequence is not obligatory for translation initiation; instead, other signals, such as the RBS spacer, may have an overarching influence on translation of mRNAs. Subsequent analyses of the 5' secondary structure of these mRNAs may provide further insight into the translation initiation mechanism.
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Affiliation(s)
- Damilola Omotajo
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, 77341, USA
| | - Travis Tate
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, 77341, USA
| | - Hyuk Cho
- Department of Computer Science, Sam Houston State University, Huntsville, TX, 77341, USA
| | - Madhusudan Choudhary
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, 77341, USA.
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19
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Pop C, Rouskin S, Ingolia NT, Han L, Phizicky EM, Weissman JS, Koller D. Causal signals between codon bias, mRNA structure, and the efficiency of translation and elongation. Mol Syst Biol 2014; 10:770. [PMID: 25538139 PMCID: PMC4300493 DOI: 10.15252/msb.20145524] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Ribosome profiling data report on the distribution of translating ribosomes, at steady-state, with codon-level resolution. We present a robust method to extract codon translation rates and protein synthesis rates from these data, and identify causal features associated with elongation and translation efficiency in physiological conditions in yeast. We show that neither elongation rate nor translational efficiency is improved by experimental manipulation of the abundance or body sequence of the rare AGG tRNA. Deletion of three of the four copies of the heavily used ACA tRNA shows a modest efficiency decrease that could be explained by other rate-reducing signals at gene start. This suggests that correlation between codon bias and efficiency arises as selection for codons to utilize translation machinery efficiently in highly translated genes. We also show a correlation between efficiency and RNA structure calculated both computationally and from recent structure probing data, as well as the Kozak initiation motif, which may comprise a mechanism to regulate initiation.
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Affiliation(s)
- Cristina Pop
- Computer Science Department, Stanford University, Stanford, CA, USA
| | - Silvi Rouskin
- Department of Cellular and Molecular Pharmacology, California Institute of Quantitative Biology, Center for RNA Systems Biology, Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lu Han
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, USA
| | - Eric M Phizicky
- School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, California Institute of Quantitative Biology, Center for RNA Systems Biology, Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Daphne Koller
- Computer Science Department, Stanford University, Stanford, CA, USA
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20
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Kjos M, Oppegård C, Diep DB, Nes IF, Veening JW, Nissen-Meyer J, Kristensen T. Sensitivity to the two-peptide bacteriocin lactococcin G is dependent on UppP, an enzyme involved in cell-wall synthesis. Mol Microbiol 2014; 92:1177-87. [PMID: 24779486 DOI: 10.1111/mmi.12632] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2014] [Indexed: 11/30/2022]
Abstract
Most bacterially produced antimicrobial peptides (bacteriocins) are thought to kill target cells by a receptor-mediated mechanism. However, for most bacteriocins the receptor is unknown. For instance, no target receptor has been identified for the two-peptide bacteriocins (class IIb), whose activity requires the combined action of two individual peptides. To identify the receptor for the class IIb bacteriocin lactococcin G, which targets strains of Lactococcus lactis, we generated 12 lactococcin G-resistant mutants and performed whole-genome sequencing to identify mutations causing the resistant phenotype. Remarkably, all had a mutation in or near the gene uppP (bacA), encoding an undecaprenyl pyrophosphate phosphatase; a membrane protein involved in peptidoglycan synthesis. Nine mutants had stop codons or frameshifts in the uppP gene, two had point mutations in putative regulatory regions and one caused an amino acid substitution in UppP. To verify the receptor function of UppP, it was shown that growth of non-sensitive Streptococcus pneumoniae could be inhibited by lactococcin G when L. lactis uppP was expressed in this bacterium. Furthermore, we show that the related class IIb bacteriocin enterocin 1071 also uses UppP as receptor. The approach used here should be broadly applicable to identify receptors for other bacteriocins as well.
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Affiliation(s)
- Morten Kjos
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, 1432, Ås, Norway; Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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21
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Abstract
Although the mapping of codon to amino acid is conserved across nearly all species, the frequency at which synonymous codons are used varies both between organisms and between genes from the same organism. This variation affects diverse cellular processes including protein expression, regulation, and folding. Here, we mathematically model an additional layer of complexity and show that individual codon usage biases follow a position-dependent exponential decay model with unique parameter fits for each codon. We use this methodology to perform an in-depth analysis on codon usage bias in the model organism Escherichia coli. Our methodology shows that lowly and highly expressed genes are more similar in their codon usage patterns in the 5′-gene regions, but that these preferences diverge at distal sites resulting in greater positional dependency (pD, which we mathematically define later) for highly expressed genes. We show that position-dependent codon usage bias is partially explained by the structural requirements of mRNAs that results in increased usage of A/T rich codons shortly after the gene start. However, we also show that the pD of 4- and 6-fold degenerate codons is partially related to the gene copy number of cognate-tRNAs supporting existing hypotheses that posit benefits to a region of slow translation in the beginning of coding sequences. Lastly, we demonstrate that viewing codon usage bias through a position-dependent framework has practical utility by improving accuracy of gene expression prediction when incorporating positional dependencies into the Codon Adaptation Index model.
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Affiliation(s)
- Adam J Hockenberry
- Department of Chemical and Biological Engineering, Northwestern UniversityInterdepartmental Program in Biological Sciences, Northwestern University
| | - M Irmak Sirer
- Department of Chemical and Biological Engineering, Northwestern University
| | - Luís A Nunes Amaral
- Department of Chemical and Biological Engineering, Northwestern UniversityNorthwestern Institute on Complex Systems, Northwestern UniversityHoward Hughes Medical Institute, Northwestern University
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern UniversityInterdepartmental Program in Biological Sciences, Northwestern UniversityNorthwestern Institute on Complex Systems, Northwestern UniversityChemistry of Life Processes Institute, Northwestern UniversityInstitute for BioNanotechnology and Medicine, Northwestern University
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22
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Soldatov RA, Vinogradova SV, Mironov AA. RNASurface: fast and accurate detection of locally optimal potentially structured RNA segments. ACTA ACUST UNITED AC 2013; 30:457-63. [PMID: 24292360 DOI: 10.1093/bioinformatics/btt701] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
MOTIVATION During the past decade, new classes of non-coding RNAs (ncRNAs) and their unexpected functions were discovered. Stable secondary structure is the key feature of many non-coding RNAs. Taking into account huge amounts of genomic data, development of computational methods to survey genomes for structured RNAs remains an actual problem, especially when homologous sequences are not available for comparative analysis. Existing programs scan genomes with a fixed window by efficiently constructing a matrix of RNA minimum free energies. A wide range of lengths of structured RNAs necessitates the use of many different window lengths that substantially increases the output size and computational efforts. RESULTS In this article, we present an algorithm RNASurface to efficiently scan genomes by constructing a matrix of significance of RNA secondary structures and to identify all locally optimal structured RNA segments up to a predefined size. RNASurface significantly improves precision of identification of known ncRNA in Bacillus subtilis. AVAILABILITY AND IMPLEMENTATION RNASurface C source code is available from http://bioinf.fbb.msu.ru/RNASurface/downloads.html.
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Affiliation(s)
- Ruslan A Soldatov
- Institute for Information Transmission Problems (the Kharkevich Institute), Russian Academy of Sciences, 19 Bolshoy Karetny per., Moscow 127994 and Department of Bioengineering and Bioinformatics, Moscow State University, 1-73 Vorobyevy Gory, Moscow 119991, Russia
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23
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Gaultney RA, Gonzalez T, Floden AM, Brissette CA. BB0347, from the lyme disease spirochete Borrelia burgdorferi, is surface exposed and interacts with the CS1 heparin-binding domain of human fibronectin. PLoS One 2013; 8:e75643. [PMID: 24086600 PMCID: PMC3785480 DOI: 10.1371/journal.pone.0075643] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 08/16/2013] [Indexed: 11/18/2022] Open
Abstract
The causative agent of Lyme disease, Borrelia burgdorferi, codes for several known fibronectin-binding proteins. Fibronectin a common the target of diverse bacterial pathogens, and has been shown to be essential in allowing for the development of certain disease states. Another borrelial protein, BB0347, has sequence similarity with these other known fibronectin-binding proteins, and may be important in Lyme disease pathogenesis. Herein, we perform an initial characterization of BB0347 via the use of molecular and biochemical techniques. We found that BB0347 is expressed, produced, and presented on the outer surface of intact B. burgdorferi. We also demonstrate that BB0347 has the potential to be important in Lyme disease progression, and have begun to characterize the nature of the interaction between human fibronectin and this bacterial protein. Further work is needed to define the role of this protein in the borrelial infection process.
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Affiliation(s)
- Robert A. Gaultney
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Edwin C. James Medical Research Facility Grand Forks, North Dakota, United States of America
| | - Tammy Gonzalez
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Edwin C. James Medical Research Facility Grand Forks, North Dakota, United States of America
| | - Angela M. Floden
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Edwin C. James Medical Research Facility Grand Forks, North Dakota, United States of America
| | - Catherine A. Brissette
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Edwin C. James Medical Research Facility Grand Forks, North Dakota, United States of America
- * E-mail:
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24
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Mao Y, Li Q, Wang W, Liang P, Tao S. Number variation of high stability regions is correlated with gene functions. Genome Biol Evol 2013; 5:484-93. [PMID: 23407773 PMCID: PMC3622296 DOI: 10.1093/gbe/evt020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Various regulatory elements in messenger RNAs (mRNAs) carrying the secondary structure play important roles in a wide range of expression processes. Numerous recent works have focused on the discovery of these functional elements that contain the conserved mRNA structures. However, to date, regions with high structural stability have been largely overlooked. In this study, we defined high stability regions (HSRs) in the coding sequences (CDSs) in bacteria based on the normalized folding free energy. We found that CDSs had high number of HSRs, and these HSRs showed high structural context robustness compared with random sequences, indicating a direct selective constraint imposed on HSRs. A reduced ribosome speed was detected near the start position of HSR, implying a possibility that HSR acted as obstacle to drive translational pausing that coordinated protein synthesis. Interestingly, we found that genes with high HSR density were enriched in the processes of translation, protein folding, and cell division. In addition, essential genes exhibited higher HSR density than nonessential genes. Overall, our study presented the previously unappreciated correlation between the number variation of HSRs and cellular processes.
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Affiliation(s)
- Yuanhui Mao
- College of life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, Shaanxi, China
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25
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Bentele K, Saffert P, Rauscher R, Ignatova Z, Blüthgen N. Efficient translation initiation dictates codon usage at gene start. Mol Syst Biol 2013; 9:675. [PMID: 23774758 PMCID: PMC3964316 DOI: 10.1038/msb.2013.32] [Citation(s) in RCA: 192] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/14/2013] [Indexed: 12/18/2022] Open
Abstract
Rare codons are enriched at gene start in many genomes. Genome analysis and experimental testing show that this enrichment evolved to keep the ribosome binding site free from stable mRNA structures, in order to facilitate efficient translation initiation. ![]()
The use of rare codons coincides with suppression of mRNA structures at the ribosome binding site across genomes. There is preferential selection for synonymous codons that reduce GC-content at the beginning of genes and a stronger pressure for rare codon usage in GC-rich organisms. Amino acids encoded by AU-rich codons are preferred at gene start. Experimental results show that mRNA structure at translation start strongly influences protein yield.
The genetic code is degenerate; thus, protein evolution does not uniquely determine the coding sequence. One of the puzzles in evolutionary genetics is therefore to uncover evolutionary driving forces that result in specific codon choice. In many bacteria, the first 5–10 codons of protein-coding genes are often codons that are less frequently used in the rest of the genome, an effect that has been argued to arise from selection for slowed early elongation to reduce ribosome traffic jams. However, genome analysis across many species has demonstrated that the region shows reduced mRNA folding consistent with pressure for efficient translation initiation. This raises the possibility that unusual codon usage is a side effect of selection for reduced mRNA structure. Here we discriminate between these two competing hypotheses, and show that in bacteria selection favours codons that reduce mRNA folding around the translation start, regardless of whether these codons are frequent or rare. Experiments confirm that primarily mRNA structure, and not codon usage, at the beginning of genes determines the translation rate.
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Affiliation(s)
- Kajetan Bentele
- Institute for Theoretical Biology, Humboldt Universität zu Berlin, Berlin, Germany
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26
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Directed evolution study unveiling key sequence factors that affect translation efficiency in Escherichia coli. J Biosci Bioeng 2013; 116:540-5. [PMID: 23790548 DOI: 10.1016/j.jbiosc.2013.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/23/2022]
Abstract
Synonymous mutations in protein coding genes significantly impact translation efficiency. We synthesized a pair of genes encoding green fluorescent protein that were separated by 160 synonymous mutations to investigate key factors that affect translation efficiency. One sequence was optimized for Escherichia coli (GFP(Eco)) and the other for Bacillus subtilis (GFP(Bsu)). When the genes were expressed in E. coli, GFP(Eco) fluoresced 12-fold stronger than GFP(Bsu), confirming the suboptimal nature of the GFP(Bsu) gene. We then employed directed evolution to improve the expression of GFP(Bsu). Random mutagenesis and DNA shuffling was used to generate mutant libraries, which were screened for fluorescence. A variant showing 6-fold fluorescence enhancement was identified, which contained a single mutation (G10A) in a rare codon for Gly-4. However, the substitution generated another type of rare codon, AGA, for Arg, suggesting that the improvement was caused by a factor other than the rare codon. We next applied saturation mutagenesis to Gly-4. The darkest variant contained a GGG codon (GFP(Bsu)-G) for Gly-4. Taking the location of the mutation into account, we hypothesized that destabilization of the mRNA secondary structure around the initiation codon improved the expression. We then randomized the nucleotide triplet in 5'-untranslated region (5'UTR) of GFP(Bsu), which is complementary to the Gly-4 codon. A variant showing 6-fold fluorescence enhancement was identified, which exhibited a destabilized secondary structure. When this 5'UTR sequence was combined with GFP(Bsu)-G, 22-fold fluorescent improvement was achieved. Collectively, the stability of the mRNA secondary structure around the initiation codon predominantly affected the translation efficiency.
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27
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Ding Y, Shah P, Plotkin JB. Weak 5'-mRNA secondary structures in short eukaryotic genes. Genome Biol Evol 2013; 4:1046-53. [PMID: 23034215 PMCID: PMC3490412 DOI: 10.1093/gbe/evs082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Experimental studies of translation have found that short genes tend to exhibit greater densities of ribosomes than long genes in eukaryotic species. It remains an open question whether the elevated ribosome density on short genes is due to faster initiation or slower elongation dynamics. Here, we address this question computationally using 5′-mRNA folding energy as a proxy for translation initiation rates and codon bias as a proxy for elongation rates. We report a significant trend toward reduced 5′-secondary structure in shorter coding sequences, suggesting that short genes initiate faster during translation. We also find a trend toward higher 5′-codon bias in short genes, suggesting that short genes elongate faster than long genes. Both of these trends hold across a diverse set of eukaryotic taxa. Thus, the elevated ribosome density on short eukaryotic genes is likely caused by differential rates of initiation, rather than differential rates of elongation.
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Affiliation(s)
- Yang Ding
- Department of Biology, University of Pennsylvania, PA, USA
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Mao Y, Wang W, Cheng N, Li Q, Tao S. Universally increased mRNA stability downstream of the translation initiation site in eukaryotes and prokaryotes. Gene 2013; 517:230-5. [PMID: 23313297 DOI: 10.1016/j.gene.2012.12.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/03/2012] [Indexed: 11/26/2022]
Abstract
Local secondary structures in coding sequences have important functions across various translational processes. To date, however, the local structures and their functions in the early stage of translation elongation remain poorly understood. Here, we surveyed the structural stability in the first 180 nucleotides of the coding sequence of 27 species using computational method. We found that the structural stability in the 30-80 nucleotide interval was significantly higher than that in other regions in eukaryotes and most prokaryotes. No significant correlation between local translation efficiency and structural stability was observed, suggesting that this structural region has undergone selection pressure directly to maintain high stability. Furthermore, ribosome was blocked by this region, providing an opportunity for co-translational regulation. Remarkably, in eukaryotes, we found that mRNAs with higher structural stability in the 30-80 nucleotide interval tended to encode the secreted proteins. Overall, our results revealed a previously unappreciated correlation between structural stability and protein localization.
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Affiliation(s)
- Yuanhui Mao
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
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Bull JJ, Molineux IJ, Wilke CO. Slow fitness recovery in a codon-modified viral genome. Mol Biol Evol 2012; 29:2997-3004. [PMID: 22532576 DOI: 10.1093/molbev/mss119] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Extensive synonymous codon modification of viral genomes appears to be an effective way of attenuating strains for use as live vaccines. An assumption of this method is that codon changes have individually small effects, such that codon-attenuated viruses will be slow to evolve back to high fitness (and thus to high virulence). The major capsid gene of the bacterial virus T7 was modified to have varying levels of suboptimal synonymous codons in different constructs, and fitnesses declined linearly with the number of changes. Adaptation of the most extreme design, with 182 codon changes, resulted in a slow fitness recovery by standards of previous experimental evolution with this virus, although fitness effects of substitutions were higher than expected from the average effect of an engineered codon modification. Molecular evolution during recovery was modest, and changes evolved both within the modified gene and outside it. Some changes within the modified gene evolved in parallel across replicates, but with no obvious explanation. Overall, the study supports the premise that codon-modified viruses recover fitness slowly, although the evolution is substantially more rapid than expected from the design principle.
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Affiliation(s)
- J J Bull
- The Institute for Cellular and Molecular Biology, The University of Texas at Austin.
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