Maximizing Transcription Efficiency Causes Codon Usage Bias

Genetics ◽  
1996 ◽  
Vol 144 (3) ◽  
pp. 1309-1320 ◽  
Author(s):  
Xuhua Xia
Keyword(s):  
Protein Synthesis ◽  
Metabolic Rate ◽  
Codon Usage ◽  
High Metabolic Rate ◽  
Initiation Rate ◽  
Synonymous Codons ◽  
Mrna Concentration ◽  
Initiation Of Translation ◽  
Transcription Efficiency ◽  
Transcriptional Process

Abstract The rate of protein synthesis depends on both the rate of initiation of translation and the rate of elongation of the peptide chain. The rate of initiation depends on the encountering rate between ribosomes and mRNA; this rate in turn depends on the concentration of ribosomes and mRNA. Thus, patterns of codon usage that increase transcriptional efficiency should increase mRNA concentration, which in turn would increase the initiation rate and the rate of protein synthesis. An optimality model of the transcriptional process is presented with the prediction that the most frequently used ribonuclectide at the third codon sites in mRNA molecules should be the same as the most abundant ribonucleotide in the cellular matrix where mRNA is transcribed. This prediction is supported by four kinds of evidence. First, A-ending codons are the most frequently used synonymous codons in mitochondria, where ATP is much more abundant than that of the three other ribonucleotides. Second, A-ending codons are more frequently used in mitochondrial genes than in nuclear genes. Third, protein genes from organisms with a high metabolic rate use more A-ending codons and have higher A content in their introns than those from organisms with a low metabolic rate.

scholarly journals Human Retrovirus Codon Usage from tRNA Point of View: Therapeutic Insights

2013 ◽  
Vol 7 ◽  
pp. BBI.S12093 ◽  
Author(s):  
Diego Frias ◽  
Joana P. Monteiro-Cunha ◽  
Aline C. Mota-Miranda ◽  
Vagner S. Fonseca ◽  
Tulio De Oliveira ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Codon Usage ◽  
Supply And Demand ◽  
Mrna Translation ◽  
Protein Translation ◽  
Point Of View ◽  
T Score ◽  
Synonymous Codons ◽  
Trna Species ◽  
Gene Data

The purpose of this study was to investigate the balance between transfer ribonucleic acid (tRNA) supply and demand in retrovirus-infected cells, seeking the best targets for antiretroviral therapy based on the hypothetical tRNA Inhibition Therapy (TRIT). Codon usage and tRNA gene data were retrieved from public databases. Based on logistic principles, a therapeutic score (T-score) was calculated for all sense codons, in each retrovirus-host system. Codons that are critical for viral protein translation, but not as critical for the host, have the highest T-score values. Theoretically, inactivating the cognate tRNA species should imply a severe reduction of the elongation rate during viral mRNA translation. We developed a method to predict tRNA species critical for retroviral protein synthesis. Four of the best TRIT targets in HIV-1 and HIV-2 encode Large Hydrophobic Residues (LHR), which have a central role in protein folding. One of them, codon CUA, is also a TRIT target in both HTLV-1 and HTLV-2. Therefore, a drug designed for inactivating or reducing the cytoplasmatic concentration of tRNA species with anticodon TAG could attenuate significantly both HIV and HTLV protein synthesis rates. Inversely, replacing codons ending in UA by synonymous codons should increase the expression, which is relevant for DNA vaccine design.

The effect of expression levels on codon usage inPlasmodium falciparum

Parasitology ◽  
2004 ◽  
Vol 128 (3) ◽  
pp. 245-251 ◽  
Author(s):  
L. PEIXOTO ◽  
V. FERNÁNDEZ ◽  
H. MUSTO
Keyword(s):  
Amino Acids ◽  
Plasmodium Falciparum ◽  
Natural Selection ◽  
Codon Usage ◽  
Complete Sequence ◽  
Expression Data ◽  
Expression Levels ◽  
Synonymous Codons ◽  
Translational Selection ◽  
Highly Expressed Genes

The usage of alternative synonymous codons in the completely sequenced, extremely A+T-rich parasitePlasmodium falciparumwas studied. Confirming previous studies obtained with less than 3% of the total genes recently described, we found that A- and U-ending triplets predominate but translational selection increases the frequency of a subset of codons in highly expressed genes. However, some new results come from the analysis of the complete sequence. First, there is more variation in GC3 than previously described; second, the effect of natural selection acting at the level of translation has been analysed with real expression data at 4 different stages and third, we found that highly expressed proteins increment the frequency of energetically less expensive amino acids. The implications of these results are discussed.

scholarly journals Caspase-mediated cleavage of eukaryotic translation initiation factor subunit 2α

1999 ◽  
Vol 342 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Shinya SATOH ◽  
Makoto HIJIKATA ◽  
Hiroshi HANDA ◽  
Kunitada SHIMOTOHNO
Keyword(s):  
Protein Synthesis ◽  
Translation Initiation ◽  
Caspase 3 ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation Initiation Factor ◽  
Α Subunit ◽  
Eukaryotic Translation ◽  
Initiation Of Translation ◽  
Eukaryotic Translation Initiation

Eukaryotic translation initiation factor 2α (eIF-2α), a target molecule of the interferon-inducible double-stranded-RNA-dependent protein kinase (PKR), was cleaved in apoptotic Saos-2 cells on treatment with poly(I)˙poly(C) or tumour necrosis factor α. This cleavage occurred with a time course similar to that of poly(ADP-ribose) polymerase, a well-known caspase substrate. In addition, eIF-2α was cleaved by recombinant active caspase-3 in vitro. By site-directed mutagenesis, the cleavage site was mapped to an Ala-Glu-Val-Asp300 ↓ Gly301 sequence located in the C-terminal portion of eIF-2α. PKR phosphorylates eIF-2α on Ser51, resulting in the suppression of protein synthesis. PKR-mediated translational suppression was repressed when the C-terminally cleaved product of eIF-2α was overexpressed in Saos-2 cells, even though PKR can phosphorylate this cleaved product. These results suggest that caspase-3 or related protease(s) can modulate the efficiency of protein synthesis by cleaving the α subunit of eIF-2, a key component in the initiation of translation.

Viral Susceptibility and Embryonic Differentiation.

Development ◽  
1963 ◽  
Vol 11 (4) ◽  
pp. 757-764
Author(s):  
Juhani Rapola ◽  
Tapani Vainio ◽  
Lauri Saxén
Keyword(s):  
Tissue Culture ◽  
Viral Replication ◽  
Metabolic Rate ◽  
Tissue Damage ◽  
Embryonic Tissue ◽  
High Metabolic Rate ◽  
Viral Susceptibility ◽  
Proliferative Rate ◽  
Active Proliferation ◽  
Severe Tissue

The fact that viral susceptibility changes during embryogenesis has been pointed out by both experimental embryologists and clinical practitioners, not to mention virologists working with avian material. In attempts to find the fundamental factors which make embryonic tissue susceptible or resistant to a given virus, the metabolic and proliferative rate have been considered relevant (Williamson et al., 1953; Robertson et al., 1955; Töndury, 1956). Experience accumulated in studies of the replication of various viruses in tissue culture has taught us that a high metabolic rate and active proliferation may not always enhance viral replication (Ginsberg, 1958). However, there seems to be justification for the view that an injurious agent leads to more severe tissue damage when it exercises its effect upon actively proliferating tissues than when it does so at the ‘resting stage’.

Rare Human Codons and HCMV Translational Regulation

2017 ◽  
Vol 27 (4) ◽  
pp. 213-216 ◽  
Author(s):  
Darja Kanduc
Keyword(s):  
Protein Synthesis ◽  
Codon Usage ◽  
Human Cytomegalovirus ◽  
Translational Regulation ◽  
Protein Production ◽  
Nucleotide Sequences ◽  
Positive Correlation ◽  
Human Host ◽  
Rare Codons

Restriction of protein synthesis characterizes human cytomegalovirus (HCMV) latency in the human host. In analyzing the molecular factors that hinder HCMV expression, the present study shows that HCMV genes frequently use 6 rare codons, i.e., GCG (Ala), CCG (Pro), CGT (Arg), CGC (Arg), TCG (Ser), and ACG (Thr). In some instances, the rare host codons are clustered along viral nucleotide sequences and represent the majority in sequences encoding short alanine and proline repeats. Given the positive correlation between codon usage, tRNA content, and protein production, the results support the hypothesis that HCMV usage of rare human codons might hinder HCMV protein synthesis, in this way leading to HCMV latency.

scholarly journals Codon usage bias creates a ramp of hydrogen bonding at the 5′-end in prokaryotic ORFeomes

2019 ◽  
Author(s):  
Juan C. Villada ◽  
Maria F. Duran ◽  
Patrick K. H. Lee
Keyword(s):  
Hydrogen Bonding ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Translation Efficiency ◽  
Molecular Processes ◽  
Molecular Feature ◽  
Web Based ◽  
Synonymous Codons ◽  
Double Stranded Dna ◽  
Codon Positions

Codon usage bias exerts control over a wide variety of molecular processes. The positioning of synonymous codons within coding sequences (CDSs) dictates protein expression by mechanisms such as local translation efficiency, mRNA Gibbs free energy, and protein co-translational folding. In this work, we explore how codon variants affect the position-dependent content of hydrogen bonding, which in turn influences energy requirements for unwinding double-stranded DNA. By analyzing over 14,000 bacterial, archaeal, and fungal ORFeomes, we found that Bacteria and Archaea exhibit an exponential ramp of hydrogen bonding at the 5′-end of CDSs, while a similar ramp was not found in Fungi. The ramp develops within the first 20 codon positions in prokaryotes, eventually reaching a steady carrying capacity of hydrogen bonding that does not differ from Fungi. Selection against uniformity tests proved that selection acts against synonymous codons with high content of hydrogen bonding at the 5′-end of prokaryotic ORFeomes. Overall, this study provides novel insights into the molecular feature of hydrogen bonding that is governed by the genetic code at the 5′-end of CDSs. A web-based application to analyze the position-dependent hydrogen bonding of ORFeomes has been developed and is publicly available (https://juanvillada.shinyapps.io/hbonds/).

scholarly journals Analysis of computational codon usage models and their association with translationally slow codons

2020 ◽  
Author(s):  
Gabriel Wright ◽  
Anabel Rodriguez ◽  
Jun Li ◽  
Patricia L. Clark ◽  
Tijana Milenković ◽  
...  
Keyword(s):  
Codon Usage ◽  
Computational Models ◽  
Selective Pressure ◽  
Synonymous Codon ◽  
Ground Truth ◽  
Protein Translation ◽  
Weak Correlation ◽  
Experimental Conditions ◽  
Synonymous Codons ◽  
Genome Wide

AbstractImproved computational modeling of protein translation rates, including better prediction of where translational slowdowns along an mRNA sequence may occur, is critical for understanding co-translational folding. Because codons within a synonymous codon group are translated at different rates, many computational translation models rely on analyzing synonymous codons. Some models rely on genome-wide codon usage bias (CUB), believing that globally rare and common codons are the most informative of slow and fast translation, respectively. Others use the CUB observed only in highly expressed genes, which should be under selective pressure to be translated efficiently (and whose CUB may therefore be more indicative of translation rates). No prior work has analyzed these models for their ability to predict translational slowdowns. Here, we evaluate five models for their association with slowly translated positions as denoted by two independent ribosome footprint (RFP) count experiments from S. cerevisiae, because RFP data is often considered as a “ground truth” for translation rates across mRNA sequences. We show that all five considered models strongly associate with the RFP data and therefore have potential for estimating translational slowdowns. However, we also show that there is a weak correlation between RFP counts for the same genes originating from independent experiments, even when their experimental conditions are similar. This raises concerns about the efficacy of using current RFP experimental data for estimating translation rates and highlights a potential advantage of using computational models to understand translation rates instead.

Comparative analysis of codon usage bias in Crenarchaea and Euryarchaea genome reveals differential preference of synonymous codons to encode highly expressed ribosomal and RNA polymerase proteins

2016 ◽  
Vol 95 (3) ◽  
pp. 537-549 ◽  
Author(s):  
VISHWA JYOTI BARUAH ◽  
SIDDHARTHA SANKAR SATAPATHY ◽  
BHESH RAJ POWDEL ◽  
ROCKTOTPAL KONWARH ◽  
ALAK KUMAR BURAGOHAIN ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Rna Polymerase ◽  
Codon Usage ◽  
Codon Usage Bias ◽  
Synonymous Codons
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