Eukaryotic release factors (eRFs) history

Инге-Вечтомов, С. Г.; Zhouravleva, Galina A.; Maury, Philippe

doi:10.1016/s0248-4900(03)00035-2

Cited by 112 publications

(88 citation statements)

References 148 publications

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“…Sup35, which can convert into the [PSI + ] prion, is normally a GTPase subunit of the translational termination factor responsible for the release of nascent protein chains from the ribosome (reviewed in ref. 14). Het-S/[Het-s] is a determinant for heterokaryon incompatibility (reviewed in ref.…”

Section: © 2 0 0 8 L a N D E S B I O S C I E N C E D O N O T D I S mentioning

confidence: 97%

Prion-Prion Interactions

Derkatch

Liebman²

2007

Prion

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Published previously online as a Prion AbStrActThe term prion has been used to describe self-replicating protein conformations that can convert other protein molecules of the same primary structure into its prion conformation. Several different proteins have now been found to exist as prions in Saccharomyces cerevisiae. Surprisingly, these heterologous prion proteins have a strong influence on each others' appearance and propagation, which may result from structural similarity between the prions. Both positive and negative effects of a prion on the de novo appearance of a heterologous prion have been observed in genetic studies. Other examples of reported interactions include mutual or unilateral inhibition and destabilization when two prions are present together in a single cell. In vitro work showing that one purified prion stimulates the conversion of a purified heterologous protein into a prion form, suggests that facilitation of de novo prion formation by heterologous prions in vivo is a result of a direct interaction between the prion proteins (a cross-seeding mechanism) and does not require other cellular components. However, other cellular structures, e.g., the cytoskeleton, may provide a scaffold for these interactions in vivo and chaperones can further facilitate or inhibit this process. Some negative prion-prion interactions may also occur via a direct interaction between the prion proteins. Another explanation is a competition between the prions for cellular factors involved in prion propagation or differential effects of chaperones stimulated by one prion on the heterologous prions.

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Section: © 2 0 0 8 L a N D E S B I O S C I E N C E D O N O T D I S mentioning

confidence: 97%

Prion-Prion Interactions

Derkatch

Liebman²

2007

Prion

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“…A previous report suggested that ϩ1 frameshifting might occur at a stop codon in eRF1-depleted cells (32). To address this possibility, a frameshift construct harboring a reporter in which different epitopes were positioned to distinguish between frameshifting at the PRF versus at the stop codon.…”

Section: ϫ1 Frameshifting Does Not Occur At a Stop Codon Proximal To mentioning

confidence: 99%

“…Eukaryotic release factor 1 (eRF1) was originally identified in a screen in the yeast Saccharomyces cerevisiae and was identified as a suppressor of nonsense mutations and designated SUP45 (32). Subsequent genetic and biochemical analyses demonstrated that SUP45 was a translational release factor which then also became known as eRF1 (32).…”

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confidence: 99%

“…Subsequent genetic and biochemical analyses demonstrated that SUP45 was a translational release factor which then also became known as eRF1 (32). eRF1 adopts a tertiary structure mimicking tRNAs (33) allowing it to recognize all three stop codons when they enter the ribosomal A site.…”

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confidence: 99%

“…eRF1 then mediates peptidyl-tRNA hydrolysis at the peptidyl transferase center of the ribosome to terminate translation. Mutation of eRF1 in yeast has been previously reported to promote stop codon readthrough and to increase the frequency of ϩ1 frameshift suppression (32).…”

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confidence: 99%

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Identification of a Cellular Factor That Modulates HIV-1 Programmed Ribosomal Frameshifting

Kobayashi¹,

Zhuang²,

Peltz

et al. 2010

Journal of Biological Chemistry

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Programmed ؊1 ribosomal frameshifting (PRF) is a distinctive mode of gene expression utilized by some viruses, including human immunodeficiency virus type 1 (HIV-1), to produce multiple proteins from a single mRNA. ؊1 PRF induces a subset of elongating ribosomes to shift their translational reading frame by 1 base in the 5 direction. The appropriate ratio of Gag to Gag-Pol synthesis is tightly regulated by the PRF signal which promotes ribosomes to shift frame, and even small changes in PRF efficiency, either up or down, have significant inhibitory effects upon virus production, making PRF essential for HIV-1 replication. Although little has been reported about the cellular factors that modulate HIV-1 PRF, the cis-acting elements regulating PRF have been extensively investigated, and the PRF signal of HIV-1 was shown to include a slippery site and frameshift stimulatory signal. Recently, a genome-wide screen performed to identify cellular factors that affect HIV-1 replication demonstrated that down-regulation of eukaryotic release factor 1 (eRF1) inhibited HIV-1 replication. Because of the eRF1 role in translation, we hypothesized that eRF1 is important for HIV-1 PRF. Using a dual luciferase reporter system harboring a HIV-1 PRF signal, results showed that depletion or inhibition of eRF1 enhanced PRF in yeast, rabbit reticulocyte lysates, and mammalian cells. Consistent with the eRF1 role in modulating HIV PRF, depleting eRF1 increased the Gag-Pol to Gag ratio in cells infected with replication-competent virus. The increase in PRF was independent of a proximal termination codon and did not result from increased ribosomal pausing at the slippery site. This is the first time that a cellular factor has been identified which can promote HIV-1 PRF and highlights HIV-1 PRF as essential for replication and an important but under exploited antiviral drug target.The ability of ribosomes to maintain the correct translational open reading frame (ORF) 2 is fundamental to the integrity and fidelity of protein synthesis. However, there are a number of examples in which elongating ribosomes are programmed to shift their translational ORF 1 base in either the 5Ј or 3Ј direction (Ϫ1 or ϩ1 ribosomal programmed ribosomal frameshift (PRF), respectively) to translate multiple proteins from a single mRNA (1-5). HIV-1 is one example of a virus that uses this process as an integral part of its replication cycle.The HIV-1 Gag and Pol proteins are synthesized as p55 Gag or p160Gag-Pol polyprotein precursors using the same translation start codon but different ORFs in the full-length viral mRNA (6, 7). The gag ORF is located at the 5Ј end of the viral mRNA, whereas the pol ORF is 3Ј of the HIV-1 PRF element and outof-frame with the gag ORF (Fig. 1). Therefore, the enzymatic protein products of the pol gene are only translated through a Ϫ1 PRF event (8 -10). Importantly, the frequency of the PRF is controlled precisely via the interaction between viral RNA cisacting elements and host translation factors. The frequency of the PRF in HIV-1...

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Nonsense Mutations and Suppression

Herrington

2013

Encyclopedia of Life Sciences

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A nonsense mutation occurs when a sense codon, one that codes for an amino acid, is changed to one of the chain‐termination codons, UAG, UAA or UGA. A nonsense suppressor can result from a second mutation affecting the translational apparatus. This mutation enables the cell to insert an amino acid in response to the nonsense codon, resulting in a wild‐type or near wild‐type phenotype. Some suppressor mutations change the anticodon of a transfer ribonucleic acid (tRNA) such that it can pair with the nonsense codon. Other suppressors increase the readthrough of the nonsense mutation. Readthrough occurs at low levels but changes in the ribosome, in tRNA, or in translation factors can increase readthrough by altering the initial selection steps, proofreading or quality control in decoding of the messenger RNA . Manipulation of the accuracy of translation holds promise as a method for the treatment of genetic diseases, many of which result from nonsense mutations. Key Concepts: Suppression results when one mutation counteracts the effect of another mutation to give a wild‐type phenotype. The nonsense codons UAG, UAA and UGA do not code for amino acids, but signal the end of the protein‐coding sequence in the mRNA. Nonsense suppression competes with chain termination. Errors occur during translation, and include reading a nonsense codon as sense as well as misreading and frameshifting. Decoding during elongation involves conformational changes in the ribosome, tRNA and EF‐Tu. Changes in the ribosome or other components of the translational apparatus can modify changes associated with decoding and thus enhance or reduce readthrough of nonsense codons.

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Eukaryotic release factors (eRFs) history

Cited by 112 publications

References 148 publications

Prion-Prion Interactions

Prion-Prion Interactions

Identification of a Cellular Factor That Modulates HIV-1 Programmed Ribosomal Frameshifting

Nonsense Mutations and Suppression

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