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Christopher U T Hellen
Termination of mRNA translation occurs when a stop codon enters the A site of the ribosome, and in eukaryotes is mediated by release factors eRF1 and eRF3, which form a ternary eRF1/eRF3-guanosine triphosphate (GTP) complex. eRF1 recognizes the stop codon, and after hydrolysis of GTP by eRF3, mediates release of the nascent peptide. The post-termination complex is then disassembled, enabling its constituents to participate in further rounds of translation. Ribosome recycling involves splitting of the 80S ribosome by the ATP-binding cassette protein ABCE1 to release the 60S subunit...
May 7, 2018: Cold Spring Harbor Perspectives in Biology
Angel Fernandez I Marti, Christopher A Saski, George A Manganaris, Ksenija Gasic, Carlos H Crisosto
It has recently been described that the Japanese plum "Santa Rosa" bud sport series contains variations in ripening pattern: climacteric, suppressed-climacteric and non-climacteric types. This provides an interesting model to study the role of ethylene and other key mechanisms governing fruit ripening, softening and senescence. The aim of the current study was to investigate such differences at the genomic level, using this series of plum bud sports, with special reference to genes involved in ethylene biosynthesis, signal transduction, and sugar metabolism...
2018: Frontiers in Plant Science
Mohamed A El-Esawi, Hosam O Elansary, Nader A El-Shanhorey, Amal M E Abdel-Hamid, Hayssam M Ali, Mohamed S Elshikh
Salinity stress as a major agricultural limiting factor may influence the chemical composition and bioactivity of Rosmarinus officinallis L. essential oils and leaf extracts. The application of salicylic acid (SA) hormone may alleviate salinity stress by modifying the chemical composition, gene expression and bioactivity of plant secondary metabolites. In this study, SA was applied to enhance salinity tolerance in R. officinallis. R. officinallis plants were subjected to saline water every 2 days (640, 2,000, and 4,000 ppm NaCl) and 4 biweekly sprays of SA at 0, 100, 200, and 300 ppm for 8 weeks...
2017: Frontiers in Physiology
Laura Molina-García, Rafael Giraldo
Amyloid aggregation of the eukaryotic translation terminator eRF3/Sup35p, the [PSI (+)] prion, empowers yeast ribosomes to read-through UGA stop codons. No similar functional prion, skipping a stop codon, has been found in Escherichia coli, a fact possibly due to the efficient back-up systems found in bacteria to rescue non-stop complexes. Here we report that engineering hydrophobic amyloidogenic repeats from a synthetic bacterial prion-like protein (RepA-WH1) into the E. coli releasing factor RF1 promotes its aggregation and enables ribosomes to continue with translation through a premature UAG stop codon located in a β-galactosidase reporter...
September 19, 2017: Scientific Reports
Valery N Urakov, Olga V Mitkevich, Irina V Safenkova, Michael D Ter-Avanesyan
In eukaryotes, termination of translation is controlled by polypeptide chain release factors eRF1 and eRF3, of which the former recognizes nonsense codons, while the latter interacts with eRF1 and stimulates polypeptide release from the ribosome in a GTP- dependent manner, and ABCE1, which facilitates ribosome recycling. In this work, we demonstrate that Pub1, a yeast protein known to be involved in stress granule formation, regulation of gene expression, and organization of the tubulin cytoskeleton, also plays a role in translation termination...
June 2017: FEBS Journal
Konstantin N Bulygin, Dmitri M Graifer, Codjo Hountondji, Ludmila Yu Frolova, Galina G Karpova
Here we employed site-directed cross-linking with the application of tRNA and mRNA analogues bearing an oxidized ribose at the 3'-terminus to investigate mutual arrangement of the main components of translation termination complexes formed on the human 80S ribosome bound with P site deacylated tRNA using eRF1•eRF3•GTP or eRF1 alone. In addition, we applied a model complex obtained in the same way with eRF1•eRF3•GMPPNP. We found that eRF3 content in the complexes with GTP and GMPPNP is similar, proving that eRF3 does not leave the ribosome after GTP hydrolysis...
July 2017: Biochimica et Biophysica Acta
Xiaohong Zhao, Ramon Rodriguez, Rebecca E Silberman, Joseph M Ahearn, Sheela Saidha, Kaelyn C Cummins, Evan Eisenberg, Lois E Greene
Prions arise from proteins that have two possible conformations: properly folded and non-infectious or misfolded and infectious. The [ PSI + ] yeast prion, which is the misfolded and self-propagating form of the translation termination factor eRF3 (Sup35), can be cured of its infectious conformation by overexpression of Hsp104, which helps dissolve the prion seeds. This dissolution depends on the trimming activity of Hsp104, which reduces the size of the prion seeds without increasing their number. To further understand the relationship between trimming and curing, trimming was followed by measuring the loss of GFP-labeled Sup35 foci from both strong and weak [ PSI + ] variants; the former variant has more seeds and less soluble Sup35 than the latter...
May 26, 2017: Journal of Biological Chemistry
Sichen Shao, Jason Murray, Alan Brown, Jack Taunton, V Ramakrishnan, Ramanujan S Hegde
In eukaryotes, accurate protein synthesis relies on a family of translational GTPases that pair with specific decoding factors to decipher the mRNA code on ribosomes. We present structures of the mammalian ribosome engaged with decoding factor⋅GTPase complexes representing intermediates of translation elongation (aminoacyl-tRNA⋅eEF1A), termination (eRF1⋅eRF3), and ribosome rescue (Pelota⋅Hbs1l). Comparative analyses reveal that each decoding factor exploits the plasticity of the ribosomal decoding center to differentially remodel ribosomal proteins and rRNA...
November 17, 2016: Cell
A G Matveenko, M V Belousov, S A Bondarev, S E Moskalenko, G A Zhouravleva
Translation termination is an important step in gene expression. Its correct processing is governed by eRF1 (Sup45) and eRF3 (Sup35) proteins. In Saccharomyces cerevisiae, mutations in the corresponding genes, as well as Sup35 aggregation in [PSI^(+)] cells that propagate the prion form of Sup35 lead to inaccurate stop codon recognition and, consequently, nonsense suppression. The presence of stronger prion variants results in the more efficient suppression of nonsense mutations. Previously, we proposed a synthetic lethality test that enables the identification of genes that may influence either translation termination factors or [PSI^(+)] manifestation...
September 2016: Molekuliarnaia Biologiia
Christopher K Morrison, Tanya Arseneault, Amy Novinscak, Martin Filion
Phytophthora infestans causes late blight of potato, one of the most devastating diseases affecting potato production. Alternative approaches for controlling late blight are being increasingly sought due to increasing environmental concerns over the use of chemical pesticides and the increasing resistance of P. infestans to fungicides. Our research group has isolated a new strain of Pseudomonas fluorescens (LBUM636) of biocontrol interest producing the antibiotic phenazine-1-carboxylic acid (PCA). Wild-type LBUM636 was shown to significantly inhibit the growth of Phytophthora infestans in in vitro confrontational assays whereas its isogenic mutant (phzC-; not producing PCA) only slightly altered the pathogen's growth...
March 2017: Phytopathology
Andrew G Matveenko, Polina B Drozdova, Mikhail V Belousov, Svetlana E Moskalenko, Stanislav A Bondarev, Yury A Barbitoff, Anton A Nizhnikov, Galina A Zhouravleva
[PSI(+) ] is the prion form of the translation termination factor Sup35 (eRF3); [PSI(+) ] strains display nonsense suppression. Another prion-like element, [ISP(+) ], is linked to antisuppression in a specific background. Transcriptional regulator Sfp1 was shown to be responsible for [ISP(+) ] propagation. In this work, we identified SFP1 as a multicopy inducer of [PSI(+) ]-dependent lethality. Sfp1 is likely to up-regulate transcription of genes encoding release factors; however, its overproduction increases Sup35, but not Sup45 protein level...
December 2016: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Alexandr Ivanov, Tatyana Mikhailova, Boris Eliseev, Lahari Yeramala, Elizaveta Sokolova, Denis Susorov, Alexey Shuvalov, Christiane Schaffitzel, Elena Alkalaeva
Poly(A)-binding protein (PABP) is a major component of the messenger RNA-protein complex. PABP is able to bind the poly(A) tail of mRNA, as well as translation initiation factor 4G and eukaryotic release factor 3a (eRF3a). PABP has been found to stimulate translation initiation and to inhibit nonsense-mediated mRNA decay. Using a reconstituted mammalian in vitro translation system, we show that PABP directly stimulates translation termination. PABP increases the efficiency of translation termination by recruitment of eRF3a and eRF1 to the ribosome...
September 19, 2016: Nucleic Acids Research
Wataru Horikawa, Kei Endo, Miki Wada, Koichi Ito
Ski7 functions as a cofactor in both normal mRNA turnover and non-stop mRNA decay (NSD) mRNA surveillance in budding yeast. The N-terminal region of Ski7 (Ski7N) interacts with the ski-complex and the exosome. The C-terminal region of Ski7 (Ski7C) binds guanine nucleotides and shares overall sequence and structural homology with the proteins of the translational GTPase superfamily, especially the tRNA/tRNA-mimic carrier protein subfamilies such as EF1α, eRF3, and Hbs1. Previous reports showed that Ski7N polypeptide functions adequately in vivo, while Ski7C, if any, only slightly...
2016: Scientific Reports
Xuhua Tang, Yiping Zhu, Stacey L Baker, Matthew W Bowler, Benjamin Jieming Chen, Chen Chen, J Robert Hogg, Stephen P Goff, Haiwei Song
Retroviral reverse transcriptase (RT) of Moloney murine leukemia virus (MoMLV) is expressed in the form of a large Gag-Pol precursor protein by suppression of translational termination in which the maximal efficiency of stop codon read-through depends on the interaction between MoMLV RT and peptidyl release factor 1 (eRF1). Here, we report the crystal structure of MoMLV RT in complex with eRF1. The MoMLV RT interacts with the C-terminal domain of eRF1 via its RNase H domain to sterically occlude the binding of peptidyl release factor 3 (eRF3) to eRF1...
June 22, 2016: Nature Communications
Natalia Shcherbik, Tatiana A Chernova, Yury O Chernoff, Dimitri G Pestov
Cotranslational degradation of polypeptide nascent chains plays a critical role in quality control of protein synthesis and the rescue of stalled ribosomes. In eukaryotes, ribosome stalling triggers release of 60S subunits with attached nascent polypeptides, which undergo ubiquitination by the E3 ligase Ltn1 and proteasomal degradation facilitated by the ATPase Cdc48. However, the identity of factors acting upstream in this process is less clear. Here, we examined how the canonical release factors Sup45-Sup35 (eRF1-eRF3) and their paralogs Dom34-Hbs1 affect the total population of ubiquitinated nascent chains associated with yeast ribosomes...
August 19, 2016: Nucleic Acids Research
Yury O Chernoff, Denis A Kiktev
Chaperones of the diverse ubiquitous Hsp70 family are involved in the regulation of ordered self-perpetuating protein aggregates (amyloids and prions), implicated in both devastating diseases and protein-based inheritance. Yeast ribosome-associated chaperone complex (RAC), composed of the Hsp40 protein Zuo1 and non-canonical Hsp70 protein Ssz1, mediates association of the Hsp70 chaperone Ssb with translating ribosomes. Ssb participates in co-translational protein folding, regulation of premature translation termination, and ribosome biogenesis...
November 2016: Current Genetics
Soumaya Jerbi, Béatrice Jolles, Tahar Bouceba, Olivier Jean-Jean
The eukaryotic release factor 3 (eRF3) has been involved in the control of mRNA degradation through its association with the cytoplasmic Poly(A) Binding Protein, PABP. In mammals, eRF3 N-terminal domain contains two overlapping PAM2 motifs which specifically recognize the MLLE domain of PABP. In humans, eRF3a/GSPT1 gene contains a stable GGC repeat encoding a repeat of glycine residues in eRF3a N-terminus. There are five known eRF3a/GSPT1 alleles in the human population, encoding 7, 9, 10, 11 and 12 glycines...
2016: RNA Biology
Petra Beznosková, Stanislava Gunišová, Leoš Shivaya Valášek
The molecular mechanism of stop codon recognition by the release factor eRF1 in complex with eRF3 has been described in great detail; however, our understanding of what determines the difference in termination efficiencies among various stop codon tetranucleotides and how near-cognate (nc) tRNAs recode stop codons during programmed readthrough in Saccharomyces cerevisiae is still poor. Here, we show that UGA-C as the only tetranucleotide of all four possible combinations dramatically exacerbated the readthrough phenotype of the stop codon recognition-deficient mutants in eRF1...
March 2016: RNA
Andrés López-Perrote, Raquel Castaño, Roberto Melero, Teresa Zamarro, Hitomi Kurosawa, Tetsuo Ohnishi, Akiko Uchiyama, Kyoko Aoyagi, Gretel Buchwald, Naoyuki Kataoka, Akio Yamashita, Oscar Llorca
Nonsense-mediated mRNA decay (NMD) is an mRNA degradation pathway that regulates gene expression and mRNA quality. A complex network of macromolecular interactions regulates NMD initiation, which is only partially understood. According to prevailing models, NMD begins by the assembly of the SURF (SMG1-UPF1-eRF1-eRF3) complex at the ribosome, followed by UPF1 activation by additional factors such as UPF2 and UPF3. Elucidating the interactions between NMD factors is essential to comprehend NMD, and here we demonstrate biochemically and structurally the interaction between human UPF2 and eukaryotic release factor 3 (eRF3)...
February 29, 2016: Nucleic Acids Research
Saifeng Cheng, Dao-Xiu Zhou, Yu Zhao
Roots are essential organs for anchoring plants, exploring and exploiting soil resources, and establishing plant-microorganisms communities in vascular plants. Rice has a complex root system architecture consisting of several root types, including primary roots, lateral roots, and crown roots. Crown roots constitute the major part of the rice root system and play important roles during the growing period. Recently, we have refined a mechanism that involves ERF3/WOX11 interaction is required to regulate the expression of genes in the cytokinin signaling pathway during the different stages of crown roots development in rice...
2016: Plant Signaling & Behavior
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