Polymerase-Usage Sequencing Identifies Initiation Zones With Less Bias Throughout S phase in Mouse Embryonic Stem Cells
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PROVIDER: PRJNA1189117 | ENA |
REPOSITORIES: ENA
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Project description:In mammalian cells, DNA replication can initiate from various locations even in different cycles of the same cell of origin. Various methods have been developed to map replication initiation zones (IZs) genome-wide, often finding IZs far less than expected considering the replication fork speed and genome size. In particular, IZs for later stages of S phase are under-represented, potentially due to reduced initiation events at this stage, but also likely to be due to variability in the population, requiring higher sensitivity of the methods. However, to what degree these factors contribute to the data, have not been investigated in detail. Mouse ES cells present similar density of replication initiation events throughout S phase, unlike non-ES cells. Here, we re-analyzed IZs with respect to replication timing within S phase, using data sets previously obtained for mouse ES cells. These data sets identified over 5-fold more early IZs compared to late IZs, suggesting that more than 80% of late IZs are missed. In addition, by newly establishing cell lines to carry out polymerase-usage sequencing (Pu-seq), we mapped IZs genome-wide in mouse ES cells. Pu-seq presented less bias towards early IZs, suggesting that better sensitivity for identifying IZs in late S phase.
2024-12-31 | GSE282548 | GEO
Project description:Differences in codon frequency between genomes, genes, or positions along a gene, modulate transcription and translation efficiency, leading to phenotypic and functional differences. Integrative studies quantifying the phenotypic consequences of codon usage bias at different molecular and cellular levels in human cells are lacking. Here, we present a multiscale analysis of the effects of synonymous codon recoding during heterologous gene expression in human cells. Six synonymous versions of an antibiotic resistance gene were generated, fused to a fluorescent reporter, and independently expressed in HEK293 cells. Multiscale phenotype was analysed by means of: quantitative transcriptome and proteome assessment, as proxies for gene expression; cellular fluorescence, as a proxy for single-cell level expression; and real-time cell proliferation in absence or presence of antibiotic, as a proxy for the cell fitness. We show that differences in codon usage bias strongly impact the molecular and cellular phenotype: (i) they result in large differences in mRNA and in protein levels, as well in mRNA-to-protein ratio; (ii) they introduce unpredicted splicing events; (iii) they lead to reproducible phenotypic heterogeneity; and (iv) they lead to a trade-off between the benefit of antibiotic resistance and the burden of heterologous expression. In human cells in culture, codon usage bias modulates gene expression by modifying mRNA availability and suitability for translation, leading to differences in protein levels and eventually eliciting functional phenotypic changes.
2024-05-24 | PXD038324 | Pride
Project description:Usage of synonymous codons represents a characteristic pattern of preference in each organism. It has been inferred that such bias of codon usage has evolved as a result of adaptation for efficient synthesis of proteins. Here we examined synonymous codon usage in genes of the fission yeast Schizosaccharomyces pombe, and compared codon usage bias with expression levels of the gene. In this organism, synonymous codon usage bias was correlated with expression levels of the gene; the bias was most obvious in two-codon amino acids. A similar pattern of the codon usage bias was also observed in Saccharomyces cerevisiae, Arabidopsis thaliana, and Caenorhabditis elegans, but was not obvious in Oryza sativa, Drosophila melanogaster, Takifugu rubripes and Homo sapiens. As codons of the highly expressed genes have greater influence on translational efficiency than codons of genes expressed at lower levels, it is likely that codon usage in the S. pombe genome has been optimized by translational selection through evolution. Relative amounts of mRNA for each ORF were measured by DNA microarray using genomic DNA as a reference, and the copy number of mRNA was calculated using an estimate of the total mRNA number in the cell as 100,000 copies.
2010-06-20 | E-GEOD-13554 | biostudies-arrayexpress
Project description:Usage of synonymous codons represents a characteristic pattern of preference in each organism. It has been inferred that such bias of codon usage has evolved as a result of adaptation for efficient synthesis of proteins. Here we examined synonymous codon usage in genes of the fission yeast Schizosaccharomyces pombe, and compared codon usage bias with expression levels of the gene. In this organism, synonymous codon usage bias was correlated with expression levels of the gene; the bias was most obvious in two-codon amino acids. A similar pattern of the codon usage bias was also observed in Saccharomyces cerevisiae, Arabidopsis thaliana, and Caenorhabditis elegans, but was not obvious in Oryza sativa, Drosophila melanogaster, Takifugu rubripes and Homo sapiens. As codons of the highly expressed genes have greater influence on translational efficiency than codons of genes expressed at lower levels, it is likely that codon usage in the S. pombe genome has been optimized by translational selection through evolution.
2009-04-01 | GSE13554 | GEO
Project description:tRNA regulation and amino acid usage bias reflect a coordinated metabolic adaptation in Plasmodium falciparum
| PRJNA940840 | ENA
Project description:tRNA regulation and amino acid usage bias reflect a coordinated metabolic adaptation in Plasmodium falciparum [RNA-Seq III]
| PRJNA1169869 | ENA
Project description:To study V-gene usage among antigen-specific and non-antigen-specific serum IgA antibodies in celiac disease patients, purified antibody fractions were subjected to proteomic analysis. Patients either had eastablished, untreated disease with severe intestinal inflammation or "potential" celiac disease characterized by presence of antibodies but no or mild inflammation. Quantification of the fraction of antibodies using different IGHV segments revealed that antibodies specific to the autoantigen transglutaminase 2 (TG2) displayed a bias toward usage of IGHV5-51 in agreement with previous observations. The fraction of antibodies using IGHV5-51 correlated with the degree of intestinal inflammation, indicating that production of hallmark IGHV5-51 anti-TG2 antibodies coincides with onset of clinical celiac disease.
2019-07-09 | PXD013777 | Pride
Project description:Spot intensity serves as a proxy for gene expression in dual-label microarray experiments. Dye bias is defined as an intensity difference between samples labeled with different dyes attributable to the dyes instead of the gene expression in the samples. Dye bias that is not removed by array normalization can introduce bias into comparisons between samples of interest. But if the bias is consistent across the samples for the same gene, it can be corrected by proper experimental design and analysis. If the dye bias is not consistent across samples for the same gene, but is different for different samples, then removing the bias becomes more problematic, perhaps indicating a technical limitation to the ability of fluorescent signals to accurately represent gene expression. Thus, it is important to characterize dye bias to determine: (1) whether it will be removed for all genes by array normalization, (2) whether it will not be removed by normalization but can be removed by proper experimental design and analysis and (3) whether dye bias correction is more problematic than either of these and is not easily removable. Keywords: dye swap design
2006-06-06 | GSE4982 | GEO
Project description:Codon usage bias is the preferential or non-random use of synonymous codons, a ubiquitous phenomenon observed in bacteria, plants and animals. Different species have consistent and characteristic codon biases. Codon bias varies not only with species, family or group within kingdom, but also between the genes within an organism. Codon usage bias has evolved through mutation, natural selection, and genetic drift in various organisms. Genome composition, GC content, expression level and length of genes, position and context of codons in the genes, recombination rates, mRNA folding, and tRNA abundance and interactions are some factors influencing codon bias. The factors shaping codon bias may also be involved in evolution of the universal genetic code. Codon-usage bias is critical factor determining gene expression and cellular function by influencing diverse processes such as RNA processing, protein translation and protein folding. Codon usage bias reflects the origin, mutation patterns and evolution of the species or genes. Investigations of codon bias patterns in genomes can reveal phylogenetic relationships between organisms, horizontal gene transfers, molecular evolution of genes and identify selective forces that drive their evolution. Most important application of codon bias analysis is in the design of transgenes, to increase gene expression levels through codon optimization, for development of transgenic crops. The review gives an overview of deviations of genetic code, factors influencing codon usage or bias, codon usage bias of nuclear and organellar genes, computational methods to determine codon usage and the significance as well as applications of codon usage analysis in biological research, with emphasis on plants.
| S-EPMC8613526 | biostudies-literature