Yeast elongation factor homolog New1 protects a subset of mRNAs from degradation by no-go decay
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE275093 | GEO | 2024/11/26
REPOSITORIES: GEO
Similar Datasets
Project description:Diphthamide (DPH) is a conserved amino acid modification on eukaryotic translation elongation factor eEF2. We show that loss of DPH increases -1 ribosomal frameshifting at both programmed, including in SARS-CoV-2, and non-programmed sites. Ribosome profiling of yeast and mammalian cells lacking DPH reveals increased ribosomal drop-off during elongation. The drop-off defect on the long yeast MDN1 gene was suppressed by eliminating out-of-frame stop codons. Our data reveal that loss of DPH impairs the fidelity of translocation during translation elongation resulting in increased rates of ribosomal frameshifting and premature termination at out-of-frame stop codons.
2023-01-10 | GSE176169 | GEO
Project description:Elongation factor P (EF-P) is required to enhance peptidyl transferase on pausing ribosomes, which can be induced by certain codons on mRNA. It regulates expression of genes in specific conditions. Therefore, to search EF-P mediated ribosome stalling motif, ribosome profiling has been used on organisms such as yeast and E. coli. However, it has not been addressed on the intracellular pathogen Salmonella Typhimurium. Through the ribosome profiling, 135 sites in 128 genes were identified as EF-P dependent sequences and many of these sites had consecutive proline codons specifically at P site of the ribosome. As a motif level, PPG was the most abundant amino acid sequence at EPA site of the ribosome and followed by APP and DPP sequence. Also, our findings revealed that salmonella-specific gene, ugtL, is regulated by frameshifting caused during translation as ribosome stalled in the DPP motif. In addition, we showed that both proline motif and EF-P are engaged in this regulation, and it affects the resistance to antimicrobial peptides. In conclusion, this study emphasized the importance of poly proline motif on EF-P and suggested a possible mechanism how EF-P affects the physiology of Salmonella.
2024-07-01 | GSE249725 | GEO
Project description:This translation model consists of 274 biochemical reactions, including 119 reactions with non-linear kinetics. This mechanistic model accounts for the concentrations of mRNA, the ribosome, the different charged tRNAs, and the elongation factors Ts (EF-Ts) and Tu (EF-Tu). We fully parameterized the model with molecular masses and kinetic constants measured experimentally; the only exceptions are the initiation parameters, which were previously estimated from gene expression data, and the ribosomal Michaelis constant for the ternary complexes, which was estimated based on the diffusion limit and hence represents a lower bound. The model is based purely on biochemical and biophysical considerations; it contains no free parameters for fitting, nor does it include any explicit growth-rate dependencies. This model is used to test our hypothesis that, to maximize the E. coli growth rate in a given environment, natural selection minimizes the total cost of translation components utilized to achieve the required protein production rate.
2020-07-01 | MODEL2006210001 | BioModels
Project description:Key protein adapters couple translation to mRNA decay on specific classes of problematic mRNAs in eukaryotes. Slow decoding on nonoptimal codons leads to codon-optimality-mediated decay (COMD) and prolonged arrest at stall sites leads to no-go decay (NGD). The identities of the decay factors underlying these processes and the mechanisms by which they respond to translational distress remain open areas of investigation. We use carefully-designed reporter mRNAs to perform genetic screens and functional assays in S. cerevisiae. We characterize the roles of Hel2 and Syh1 in coordinating translational repression and mRNA decay on NGD reporter mRNAs, finding that Syh1 acts as the primary link to mRNA decay in NGD. Importantly we, observe that these NGD factors are not involved in the degradation of mRNAs enriched in nonoptimal codons. Further, we establish that key factors previously implicated in COMD, Not5 and Dhh1 , contribute modestly to the degradation of an NGD-targeted mRNA. Finally, we use ribosome profiling to reveal distinct ribosomal states associated with each reporter mRNA that readily rationalize the contributions of NGD and COMD factors to degradation of these reporters. Taken together, these results provide new mechanistic insight into the role of Syh1 in NGD and define the molecular triggers that determine how distinct pathways target mRNAs for degradation in yeast.
2022-08-08 | GSE189404 | GEO
Project description:Key protein adapters couple translation to mRNA decay on specific classes of problematic mRNAs in eukaryotes. Slow decoding on nonoptimal codons leads to codon-optimality-mediated decay (COMD) and prolonged arrest at stall sites leads to no-go decay (NGD). The identities of the decay factors underlying these processes and the mechanisms by which they respond to translational distress remain open areas of investigation. We use carefully-designed reporter mRNAs to perform genetic screens and functional assays in S. cerevisiae. We characterize the roles of Hel2 and Syh1 in coordinating translational repression and mRNA decay on NGD reporter mRNAs, finding that Syh1 acts as the primary link to mRNA decay in NGD. Importantly we, observe that these NGD factors are not involved in the degradation of mRNAs enriched in nonoptimal codons. Further, we establish that key factors previously implicated in COMD, Not5 and Dhh1 , contribute modestly to the degradation of an NGD-targeted mRNA. Finally, we use ribosome profiling to reveal distinct ribosomal states associated with each reporter mRNA that readily rationalize the contributions of NGD and COMD factors to degradation of these reporters. Taken together, these results provide new mechanistic insight into the role of Syh1 in NGD and define the molecular triggers that determine how distinct pathways target mRNAs for degradation in yeast.
2022-08-08 | PXD030076 | Pride
Project description:The recycling of ribosomal subunits after translation termination is critical for efficient gene expression. Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR) function as 40S recycling factors in vitro, but it is unknown whether they perform this function in vivo or serve as alternative initiation factors. Ribosome profiling of strains missing these factors revealed 80S ribosomes queued behind the stop codon, consistent with a block in 40S recycling. We found that unrecycled ribosomes could reinitiate translation at AUG codons in the 3’UTR, as evidenced by peaks in the footprint data and 3’UTR reporter analysis. In vitro translation experiments using reporter mRNAs containing upstream ORFs (uORFs) further established that reinitiation increased in the absence of these proteins. In some cases, 40S ribosomes appeared to rejoin with 60S subunits and undergo an alternative 80S reinitiation process in 3’UTRs. These results support a crucial role for Tma64, Tma20, and Tma22 in the recycling of 40S ribosomal subunits at stop codons and translation reinitiation.
2018-08-30 | GSE108942 | GEO
Project description:The genetic code that specifies the identity of amino acids incorporated into proteins during protein synthesis is almost universally conserved. Mitochondrial translation, however, exhibits deviations from the standard genetic code including reassigning of two arginine codons to stop codons. Translation termination at these non-canonical stop codons requires a protein factor to release the newly synthesized polypeptide chain. Currently it is not known how, and by which release factor, these stop codons are recognized. Here, we used biochemical experiments on knockout mutants in human cells in combination with cryo-electron microscopy to establish that the unusual mitochondrial release factor 1 (mtRF1) detects the non-canonical stop codons. We show that loss of this factor leads to stalling of mitochondrial ribosomes on non-canonical stop codons. As a result, reduced levels of cytochrome C oxidase subunit 1 of the oxidative phosphorylation complex IV are synthesized leading to a defect in mitochondrial respiration. We further show that binding of mtRF1 to the decoding center of the ribosome stabilizes a highly unusual distortion in the mRNA conformation and that the ribosomal RNA importantly participates in the specific recognition of the non-canonical stop codons.
2023-05-09 | GSE216779 | GEO
Project description:The genetic code that specifies the identity of amino acids incorporated into proteins during protein synthesis is almost universally conserved. Mitochondrial translation deviates from the standard genetic code which includes the reassignment of two arginine codons into stop codons {Jukes, 1993 #438}. Translation termination at these non-canonical stop codons requires a protein factor to release the newly synthesized polypeptide chain, however, the identity of this factor is not known currently{Nadler, 2021 #406}. Here, we used gene editing and ribo-profiling in combination with cryo-electron microscopy to establish that the unusual mitochondrial release factor 1 (mtRF1) detects the non-canonical stop codons. We show that loss of mtRF1 leads to stalling of mitochondrial ribosomes on non-canonical stop codons and consequent reduced translation of cytochrome C oxidase subunit 1 that results in decreased mitochondrial respiration. We show that binding of mtRF1 to the decoding center of the ribosome stabilizes a highly unusual distortion in the mRNA conformation and that the ribosomal RNA importantly participates in the specific recognition of the non-canonical stop codons.
2023-03-21 | GSE216979 | GEO
Project description:In eukaryotic cells, many mRNAs possess upstream open reading frames (uORFs) in addition to the main coding region. After uORF translation, the ribosome could either recycle at the stop codon or resume scanning for downstream start codons in a process known as reinitiation. Accumulating evidence suggests that some initiation factors, including eIF3, linger on the early elongating ribosome, forming an eIF3-80S complex. Very little is known how the eIF3 is carried along with the 80S during elongation and its implications in subsequent translation reinitiation. Here we report that eIF3a undergoes dynamic O-GlcNAc modification in response to nutrient starvation. Stress-induced de-O-GlcNAcylation promotes eIF3 retention on the elongating ribosome and facilitates reinitiation at downstream start codons. Eliminating the modification site from eIF3a via genome editing induces ATF4 reinitiation under the nutrient rich condition. Our findings illustrate a mechanism in balancing ribosome recycling and reinitiation, thereby linking integrated stress response and translational reprogramming.
2021-11-01 | GSE181040 | GEO
Project description:Protein synthesis is performed by the ribosome and a host of highly conserved elongation factors. Elongation factor P (EF-P) prevents ribosome stalling at difficult-to-translate sequences, particularly polyproline tracts. In bacteria, phenotypes associated with efp deletion range from modest to lethal, suggesting that some species encode an additional translation factor that has similar function to EF-P. Here we identify YfmR as a translation factor that is essential in the absence of EF-P in B. subtilis. YfmR is an ABCF ATPase that is closely related to both Uup and EttA, ABCFs that bind the ribosomal E-site and are conserved in more than 50% of bacterial genomes. We show that YfmR associates with actively translating ribosomes, and that depleting YfmR from ∆efp cells causes severe ribosome stalling at a polyproline tract in vivo. YfmR depletion from ∆efp cells was lethal, and caused reduced levels of actively translating ribosomes. Our results therefore identify YfmR as an important translation factor that is essential in B. subtilis in the absence of EF-P.
2024-03-06 | GSE249203 | GEO