scholarly journals Transcriptome-wide investigation of stop codon readthrough in Saccharomyces cerevisiae

PLoS Genetics ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. e1009538
Author(s):  
Kotchaphorn Mangkalaphiban ◽  
Feng He ◽  
Robin Ganesan ◽  
Chan Wu ◽  
Richard Baker ◽  
...  
Keyword(s):  
Stop Codon ◽  
Regulatory Elements ◽  
Ribosome Profiling ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Coding Region ◽  
Genome Wide ◽  
A Genome ◽  
Stop Codon Readthrough

Translation of mRNA into a polypeptide is terminated when the release factor eRF1 recognizes a UAA, UAG, or UGA stop codon in the ribosomal A site and stimulates nascent peptide release. However, stop codon readthrough can occur when a near-cognate tRNA outcompetes eRF1 in decoding the stop codon, resulting in the continuation of the elongation phase of protein synthesis. At the end of a conventional mRNA coding region, readthrough allows translation into the mRNA 3’-UTR. Previous studies with reporter systems have shown that the efficiency of termination or readthrough is modulated by cis-acting elements other than stop codon identity, including two nucleotides 5’ of the stop codon, six nucleotides 3’ of the stop codon in the ribosomal mRNA channel, and stem-loop structures in the mRNA 3’-UTR. It is unknown whether these elements are important at a genome-wide level and whether other mRNA features proximal to the stop codon significantly affect termination and readthrough efficiencies in vivo. Accordingly, we carried out ribosome profiling analyses of yeast cells expressing wild-type or temperature-sensitive eRF1 and developed bioinformatics strategies to calculate readthrough efficiency, and to identify mRNA and peptide features which influence that efficiency. We found that the stop codon (nt +1 to +3), the nucleotide after it (nt +4), the codon in the P site (nt -3 to -1), and 3’-UTR length are the most influential features in the control of readthrough efficiency, while nts +5 to +9 had milder effects. Additionally, we found low readthrough genes to have shorter 3’-UTRs compared to high readthrough genes in cells with thermally inactivated eRF1, while this trend was reversed in wild-type cells. Together, our results demonstrated the general roles of known regulatory elements in genome-wide regulation and identified several new mRNA or peptide features affecting the efficiency of translation termination and readthrough.

scholarly journals Transcriptome-wide investigation of stop codon readthrough in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Kotchaphorn Mangkalaphiban ◽  
Feng He ◽  
Robin Ganesan ◽  
Chan Wu ◽  
Richard Baker ◽  
...  
Keyword(s):  
Stop Codon ◽  
Regulatory Elements ◽  
Ribosome Profiling ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Coding Region ◽  
Genome Wide ◽  
A Genome ◽  
Stop Codon Readthrough

Translation of mRNA into a polypeptide is terminated when the release factor eRF1 recognizes a UAA, UAG, or UGA stop codon in the ribosomal A site and stimulates nascent peptide release. However, stop codon readthrough can occur when a near-cognate tRNA outcompetes eRF1 in decoding the stop codon, resulting in the continuation of the elongation phase of protein synthesis. At the end of a conventional mRNA coding region, readthrough allows translation into the mRNA 3′-UTR. Previous studies with reporter systems have shown that the efficiency of termination or readthrough is modulated by cis-acting elements other than stop codon identity, including two nucleotides 5′ of the stop codon, six nucleotides 3′ of the stop codon in the ribosomal mRNA channel, and stem-loop structures in the mRNA 3′-UTR. It is unknown whether these elements are important at a genome-wide level and whether other mRNA features proximal to the stop codon significantly affect termination and readthrough efficiencies in vivo. Accordingly, we carried out ribosome profiling analyses of yeast cells expressing wild-type or temperature-sensitive eRF1 and developed bioinformatics strategies to calculate readthrough efficiency, and to identify mRNA and peptide features which influence that efficiency. We found that the stop codon (nt +1 to +3), the nucleotide after it (nt +4), the codon in the P site (nt -3 to -1), and 3′-UTR length are the most influential features in the control of readthrough efficiency, while nts +5 to +9 and mRNA secondary structure in the 3′-UTR had milder effects. Additionally, we found low readthrough genes to have shorter 3′-UTRs compared to high readthrough genes in cells with thermally inactivated eRF1, while this trend was reversed in wild-type cells. Together, our results demonstrated the general roles of known regulatory elements in genome-wide regulation and identified several new mRNA or peptide features affecting the efficiency of translation termination and readthrough.

scholarly journals A Genome-Wide Analysis of RNA Pseudoknots That Stimulate Efficient −1 Ribosomal Frameshifting or Readthrough in Animal Viruses

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaolan Huang ◽  
Qiang Cheng ◽  
Zhihua Du
Keyword(s):  
Large Scale ◽  
Stop Codon ◽  
Ribosomal Frameshifting ◽  
Viral Genomes ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
A Genome ◽  
Rna Pseudoknots ◽  
Rna Pseudoknot ◽  
Stop Codon Readthrough

Programmed −1 ribosomal frameshifting (PRF) and stop codon readthrough are two translational recoding mechanisms utilized by some RNA viruses to express their structural and enzymatic proteins at a defined ratio. Efficient recoding usually requires an RNA pseudoknot located several nucleotides downstream from the recoding site. To assess the strategic importance of the recoding pseudoknots, we have carried out a large scale genome-wide analysis in which we used an in-house developed program to detect all possible H-type pseudoknots within the genomic mRNAs of 81 animal viruses. Pseudoknots are detected downstream from ~85% of the recoding sites, including many previously unknown pseudoknots. ~78% of the recoding pseudoknots are the most stable pseudoknot within the viral genomes. However, they are not as strong as some designed pseudoknots that exhibit roadblocking effect on the translating ribosome. Strong roadblocking pseudoknots are not detected within the viral genomes. These results indicate that the decoding pseudoknots have evolved to possess optimal stability for efficient recoding. We also found that the sequence at thegag-polframeshift junction of HIV1 harbors potential elaborated pseudoknots encompassing the frameshift site. A novel mechanism is proposed for possible involvement of the elaborated pseudoknots in the HIV1 PRF event.

scholarly journals Stop Codon Context Influences Genome-Wide Stimulation of Termination Codon Readthrough by Aminoglycosides

2019 ◽  
Author(s):  
Jamie R Wangen ◽  
Rachel Green
Keyword(s):  
Mammalian Cells ◽  
Stop Codon ◽  
Translation Termination ◽  
Premature Termination Codon ◽  
Ribosome Profiling ◽  
Termination Codon ◽  
Stop Codons ◽  
Genome Wide ◽  
A Genome

AbstractStop codon readthrough (SCR) occurs when the ribosome miscodes at a stop codon. Such readthrough events can be therapeutically desirable when a premature termination codon (PTC) is found in a critical gene. To study SCR in vivo in a genome-wide manner, we treated mammalian cells with aminoglycosides and performed ribosome profiling. We find that in addition to stimulating readthrough of PTCs, aminoglycosides stimulate readthrough of normal termination codons (NTCs) genome-wide. Stop codon identity, the nucleotide following the stop codon, and the surrounding mRNA sequence context all influence the likelihood of SCR. In comparison to NTCs, downstream stop codons in 3′UTRs are recognized less efficiently by ribosomes, suggesting that targeting of critical stop codons for readthrough may be achievable without general disruption of translation termination. Finally, we find that G418 treatment globally alters gene expression with substantial effects on translation of histone genes, selenoprotein genes, and S-adenosylmethionine decarboxylase (AMD1).

scholarly journals Ribosome profiling reveals pervasive and regulated stop codon readthrough in Drosophila melanogaster

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Joshua G Dunn ◽  
Catherine K Foo ◽  
Nicolette G Belletier ◽  
Elizabeth R Gavis ◽  
Jonathan S Weissman
Keyword(s):  
Drosophila Melanogaster ◽  
Stop Codon ◽  
Ribosome Profiling ◽  
Terminal Protein ◽  
Regulate Gene Expression ◽  
Genome Wide ◽  
Nascent Peptide ◽  
Show Evidence ◽  
And Function ◽  
Stop Codon Readthrough

Ribosomes can read through stop codons in a regulated manner, elongating rather than terminating the nascent peptide. Stop codon readthrough is essential to diverse viruses, and phylogenetically predicted to occur in a few hundred genes in Drosophila melanogaster, but the importance of regulated readthrough in eukaryotes remains largely unexplored. Here, we present a ribosome profiling assay (deep sequencing of ribosome-protected mRNA fragments) for Drosophila melanogaster, and provide the first genome-wide experimental analysis of readthrough. Readthrough is far more pervasive than expected: the vast majority of readthrough events evolved within D. melanogaster and were not predicted phylogenetically. The resulting C-terminal protein extensions show evidence of selection, contain functional subcellular localization signals, and their readthrough is regulated, arguing for their importance. We further demonstrate that readthrough occurs in yeast and humans. Readthrough thus provides general mechanisms both to regulate gene expression and function, and to add plasticity to the proteome during evolution.

scholarly journals Stop codon context influences genome-wide stimulation of termination codon readthrough by aminoglycosides

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jamie R Wangen ◽  
Rachel Green
Keyword(s):  
Mammalian Cells ◽  
Stop Codon ◽  
Translation Termination ◽  
Premature Termination Codon ◽  
Ribosome Profiling ◽  
Termination Codon ◽  
Stop Codons ◽  
Genome Wide ◽  
A Genome

Stop codon readthrough (SCR) occurs when the ribosome miscodes at a stop codon. Such readthrough events can be therapeutically desirable when a premature termination codon (PTC) is found in a critical gene. To study SCR in vivo in a genome-wide manner, we treated mammalian cells with aminoglycosides and performed ribosome profiling. We find that in addition to stimulating readthrough of PTCs, aminoglycosides stimulate readthrough of normal termination codons (NTCs) genome-wide. Stop codon identity, the nucleotide following the stop codon, and the surrounding mRNA sequence context all influence the likelihood of SCR. In comparison to NTCs, downstream stop codons in 3′UTRs are recognized less efficiently by ribosomes, suggesting that targeting of critical stop codons for readthrough may be achievable without general disruption of translation termination. Finally, we find that G418-induced miscoding alters gene expression with substantial effects on translation of histone genes, selenoprotein genes, and S-adenosylmethionine decarboxylase (AMD1).

scholarly journals A genome-wide map of regulatory elements in zebrafish

Lab Animal ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 17-17
Author(s):  
Alexandra Le Bras
Keyword(s):  
Regulatory Elements ◽  
Genome Wide ◽  
A Genome

scholarly journals A Genome-Wide Analysis of Pathogenesis-Related Protein-1 (PR-1) Genes from Piper nigrum Reveals Its Critical Role during Phytophthora capsici Infection

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 1007
Author(s):  
Divya Kattupalli ◽  
Asha Sreenivasan ◽  
Eppurathu Vasudevan Soniya
Keyword(s):  
Phytophthora Capsici ◽  
Regulatory Elements ◽  
Piper Nigrum ◽  
Binding Motif ◽  
Altered Expression ◽  
Genome Wide ◽  
A Genome ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Black pepper (Piper nigrum L.) is a prominent spice that is an indispensable ingredient in cuisine and traditional medicine. Phytophthora capsici, the causative agent of footrot disease, causes a drastic constraint in P. nigrum cultivation and productivity. To counterattack various biotic and abiotic stresses, plants employ a broad array of mechanisms that includes the accumulation of pathogenesis-related (PR) proteins. Through a genome-wide survey, eleven PR-1 genes that belong to a CAP superfamily protein with a caveolin-binding motif (CBM) and a CAP-derived peptide (CAPE) were identified from P. nigrum. Despite the critical functional domains, PnPR-1 homologs differ in their signal peptide motifs and core amino acid composition in the functional protein domains. The conserved motifs of PnPR-1 proteins were identified using MEME. Most of the PnPR-1 proteins were basic in nature. Secondary and 3D structure analyses of the PnPR-1 proteins were also predicted, which may be linked to a functional role in P. nigrum. The GO and KEGG functional annotations predicted their function in the defense responses of plant-pathogen interactions. Furthermore, a transcriptome-assisted FPKM analysis revealed PnPR-1 genes mapped to the P. nigrum-P. capsici interaction pathway. An altered expression pattern was detected for PnPR-1 transcripts among which a significant upregulation was noted for basic PnPR-1 genes such as CL10113.C1 and Unigene17664. The drastic variation in the transcript levels of CL10113.C1 was further validated through qRT-PCR and it showed a significant upregulation in infected leaf samples compared with the control. A subsequent analysis revealed the structural details, phylogenetic relationships, conserved sequence motifs and critical cis-regulatory elements of PnPR-1 genes. This is the first genome-wide study that identified the role of PR-1 genes during P. nigrum-P. capsici interactions. The detailed in silico experimental analysis revealed the vital role of PnPR-1 genes in regulating the first layer of defense towards a P. capsici infection in Panniyur-1 plants.

Functional interaction between p21rap1A and components of the budding pathway in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (9) ◽  
pp. 4084-4092
Author(s):  
P C McCabe ◽  
H Haubruck ◽  
P Polakis ◽  
F McCormick ◽  
M A Innis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mammalian Cells ◽  
Bound States ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Amino Terminal ◽  
Loop Region

The rap1A gene encodes a 21-kDa, ras-related GTP-binding protein (p21rap1A) of unknown function. A close structural homolog of p21rap1A (65% identity in the amino-terminal two-thirds) is the RSR1 gene product (Rsr1p) of Saccharomyces cerevisiae. Although Rsr1p is not essential for growth, its presence is required for nonrandom selection of bud sites. To assess the similarity of these proteins at the functional level, wild-type and mutant forms of p21rap1A were tested for complementation of activities known to be fulfilled by Rsr1p. Expression of p21rap1A, like multicopy expression of RSR1, suppressed the conditional lethality of a temperature-sensitive cdc24 mutation. Point mutations predicted to affect the localization of p21rap1A or its ability to cycle between GDP and GTP-bound states disrupted suppression of cdc24ts, while other mutations in the 61-65 loop region improved suppression. Expression of p21rap1A could not, however, suppress the random budding phenotype of rsr1 cells. p21rap1A also apparently interfered with the normal activity of Rsrlp, causing random budding in diploid wild-type cells, suggesting an inability of p21rap1A to interact appropriately with Rsr1p regulatory proteins. Consistent with this hypothesis, we found an Rsr1p-specific GTPase-activating protein (GAP) activity in yeast membranes which was not active toward p21rap1A, indicating that p21rap1A may be predominantly GTP bound in yeast cells. Coexpression of human Rap1-specific GAP suppressed the random budding due to expression of p21rap1A or its derivatives, including Rap1AVal-12. Although Rap1-specific GAP stimulated the GTPase of Rsr1p in vitro, it did not dominantly interfere with Rsr1p function in vivo. A chimera consisting of Rap1A1-165::Rsr1p166-272 did not exhibit normal Rsr1p function in the budding pathway. These results indicated that p21rap1A and Rsr1p share at least partial functional homology, which may have implications for p21rap1A function in mammalian cells.

scholarly journals Comprehensive Genomic Discovery of Non-Coding Transcriptional Enhancers in the African Malaria Vector Anopheles coluzzii

2022 ◽  
Vol 12 ◽  
Author(s):  
Inge Holm ◽  
Luisa Nardini ◽  
Adrien Pain ◽  
Emmanuel Bischoff ◽  
Cameron E. Anderson ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Regulatory Elements ◽  
Specific Cell ◽  
Insect Vector ◽  
Anopheles Coluzzii ◽  
Gene Promoters ◽  
Transcriptional Enhancers ◽  
Genome Wide ◽  
A Genome

Almost all regulation of gene expression in eukaryotic genomes is mediated by the action of distant non-coding transcriptional enhancers upon proximal gene promoters. Enhancer locations cannot be accurately predicted bioinformatically because of the absence of a defined sequence code, and thus functional assays are required for their direct detection. Here we used a massively parallel reporter assay, Self-Transcribing Active Regulatory Region sequencing (STARR-seq), to generate the first comprehensive genome-wide map of enhancers in Anopheles coluzzii, a major African malaria vector in the Gambiae species complex. The screen was carried out by transfecting reporter libraries created from the genomic DNA of 60 wild A. coluzzii from Burkina Faso into A. coluzzii 4a3A cells, in order to functionally query enhancer activity of the natural population within the homologous cellular context. We report a catalog of 3,288 active genomic enhancers that were significant across three biological replicates, 74% of them located in intergenic and intronic regions. The STARR-seq enhancer screen is chromatin-free and thus detects inherent activity of a comprehensive catalog of enhancers that may be restricted in vivo to specific cell types or developmental stages. Testing of a validation panel of enhancer candidates using manual luciferase assays confirmed enhancer function in 26 of 28 (93%) of the candidates over a wide dynamic range of activity from two to at least 16-fold activity above baseline. The enhancers occupy only 0.7% of the genome, and display distinct composition features. The enhancer compartment is significantly enriched for 15 transcription factor binding site signatures, and displays divergence for specific dinucleotide repeats, as compared to matched non-enhancer genomic controls. The genome-wide catalog of A. coluzzii enhancers is publicly available in a simple searchable graphic format. This enhancer catalogue will be valuable in linking genetic and phenotypic variation, in identifying regulatory elements that could be employed in vector manipulation, and in better targeting of chromosome editing to minimize extraneous regulation influences on the introduced sequences.Importance: Understanding the role of the non-coding regulatory genome in complex disease phenotypes is essential, but even in well-characterized model organisms, identification of regulatory regions within the vast non-coding genome remains a challenge. We used a large-scale assay to generate a genome wide map of transcriptional enhancers. Such a catalogue for the important malaria vector, Anopheles coluzzii, will be an important research tool as the role of non-coding regulatory variation in differential susceptibility to malaria infection is explored and as a public resource for research on this important insect vector of disease.

Sign in / Sign up

Export Citation Format

Share Document