scholarly journals The Role of Nuclear Cap Binding Protein Cbc1p of Yeast in mRNA Termination and Degradation

2000 ◽  
Vol 20 (8) ◽  
pp. 2827-2838 ◽  
Author(s):  
Biswadip Das ◽  
Zijian Guo ◽  
Patrick Russo ◽  
Pascal Chartrand ◽  
Fred Sherman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mrna Export ◽  
Degradation Pathway ◽  
The Other ◽  
Nonsense Mutations ◽  
Mrna Surveillance ◽  
Nonessential Gene ◽  
Cap Binding Complex ◽  
Low Levels

ABSTRACT The cyc1-512 mutation in Saccharomyces cerevisiae causes a 90% reduction in the level of iso-1-cytochrome c because of the lack of a proper 3′-end-forming signal, resulting in low levels of eight aberrantly longcyc1-512 mRNAs which differ in length at their 3′ termini. cyc1-512 can be suppressed by deletion of either of the nonessential genes CBC1 and CBC2, which encode the CBP80 and CBP20 subunits of the nuclear cap binding complex, respectively, or by deletion of the nonessential gene UPF1, which encodes a major component of the mRNA surveillance complex. The upf1-Δ deletion suppressed the cyc1-512defect by diminishing degradation of the longer subset ofcyc1-512 mRNAs, suggesting that downstream elements or structures occurred in the extended 3′ region, similar to the downstream elements exposed by transcripts bearing premature nonsense mutations. On the other hand, suppression of cyc1-512defects by cbc1-Δ occurred by two different mechanisms. The levels of the shorter cyc1-512 transcripts were enhanced in the cbc1-Δ mutants by promoting 3′-end formation at otherwise-weak sites, whereas the levels of the longercyc1-512 transcripts, as well as of all mRNAs, were slightly enhanced by diminishing degradation. Furthermore,cbc1-Δ greatly suppressed the degradation of mRNAs and other phenotypes of a rat7-1 strain which is defective in mRNA export. We suggest that Cbc1p defines a novel degradation pathway that acts on mRNAs partially retained in nuclei.

scholarly journals The Unstable F-box Protein p58-Ctf13 Forms the Structural Core of the CBF3 Kinetochore Complex

1999 ◽  
Vol 145 (5) ◽  
pp. 933-950 ◽  
Author(s):  
Iain D. Russell ◽  
Adam S. Grancell ◽  
Peter K. Sorger
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Functional Properties ◽  
Chromosome Segregation ◽  
Half Life ◽  
Degradation Pathway ◽  
The Other ◽  
Yeast Cells ◽  
Centromeric Dna ◽  
Structural And Functional Properties ◽  
F Box Protein

Kinetochores are smaller and more accessible experimentally in budding yeast than in any other eukaryote. Believing that simple and complex kinetochores have important structural and functional properties in common, we characterized the structure of CBF3, the essential centromere-binding complex that initiates kinetochore formation in Saccharomyces cerevisiae. We find that the four subunits of CBF3 are multimeric in solution: p23Skp1 and p58Ctf13 form a heterodimer, and p64Cep3 and p110Ndc10 form homodimers. Subcomplexes involving p58 and each of the other CBF3 subunits can assemble in the absence of centromeric DNA. In these subcomplexes, p58 appears to function as a structural core mediating stable interactions among other CBF3 proteins. p58 has a short half-life in yeast, being subject to ubiquitin-dependent proteolysis, but we find that it is much more stable following association with p64. We propose that p23Skp1-p58-p64 complexes constitute the primary pool of active p58 in yeast cells. These complexes can either dissociate, reexposing p58 to the degradation pathway, or can bind to p110 and centromeric DNA, forming a functional CBF3 complex in which p58 is fully protected from degradation. This pathway may constitute an editing mechanism preventing the formation of ectopic kinetochores and ensuring the fidelity of chromosome segregation.

scholarly journals Exposure risk to carbonyl compounds and furfuryl alcohol through the consumption of sparkling wines

2019 ◽  
Vol 49 (3) ◽  
Author(s):  
Gabriela Pelizza Peterle ◽  
Karolina Cardoso Hernandes ◽  
Luana Schmidt ◽  
Júlia Barreto Hoffmann Maciel ◽  
Claudia Alcaraz Zini ◽  
...  
Keyword(s):  
Environmental Contamination ◽  
Carbonyl Compounds ◽  
Furfuryl Alcohol ◽  
Ethyl Carbamate ◽  
The Other ◽  
Exposure Risk ◽  
Low Levels ◽  
First Time

ABSTRACT: The goals of this study were to verify the occurrence of furfuryl alcohol (FA) and carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate (EC), formaldehyde and furfural) in sparkling wines and to evaluate, for the first time, whether the consumption of the samples under study could represent risk to consumers health. These compounds are electrophilic; and therefore, may covalently bind to DNA, which may result in mutagenicity. EC and formaldehyde were present at low levels (<1μg L-1) in all samples. Acetaldehyde, furfural and acrolein were also found in low levels (<1.5, 1.4 and 1.0μg L-1, respectively) in 57, 71 and 76% of samples. In the other samples, levels of acetaldehyde, furfural and acrolein ranged from 5.2 to 54.8, 10.5 to 41.0 and 20.3 to 36.7μg L-1, respectively. Furfuryl alcohol was also reported in all samples in levels from 10.4 to 33.5μg L-1. Acrolein was the only compound reported at levels sufficient to represent risk to health, which occurred in 24% of the samples. A study focused on the origin of acrolein deserves attention, investigating the influence of the concentration of precursors and the role of fermentation in the formation of this aldehyde, besides the evaluation of possible environmental contamination of grapes during cultivation.

scholarly journals Distinct Functions of the Cap-Binding Complex in Stimulation of Nuclear mRNA Export

2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Rwik Sen ◽  
Priyanka Barman ◽  
Amala Kaja ◽  
Jannatul Ferdoush ◽  
Shweta Lahudkar ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Level ◽  
Mrna Export ◽  
Mrna Splicing ◽  
Content Type ◽  
Cap Binding Complex ◽  
Cleavage And Polyadenylation ◽  
Nascent Mrna ◽  
Stimulation Of ◽  
Active Genes

ABSTRACTCap-binding complex (CBC) associates cotranscriptionally with the cap structure at the 5′ end of nascent mRNA to protect it from exonucleolytic degradation. Here, we show that CBC promotes the targeting of an mRNA export adaptor, Yra1 (forming transcription export [TREX] complex with THO and Sub2), to the active genes and enhances mRNA export inSaccharomyces cerevisiae. Likewise, recruitment of Npl3 (an hnRNP involved in mRNA export via formation of export-competent ribonuclear protein complex [RNP]) to the active genes is facilitated by CBC. Thus, CBC enhances targeting of the export factors and promotes mRNA export. Such function of CBC is not mediated via THO and Sub2 of TREX, cleavage and polyadenylation factors, or Sus1 (that regulates mRNA export via transcription export 2 [TREX-2]). However, CBC promotes splicing ofSUS1mRNA and, consequently, Sus1 protein level and mRNA export via TREX-2. Collectively, our results support the hypothesis that CBC promotes recruitment of Yra1 and Npl3 to the active genes, independently of THO, Sub2, or cleavage and polyadenylation factors, and enhances mRNA export via TREX and RNP, respectively, in addition to its role in facilitatingSUS1mRNA splicing to increase mRNA export through TREX-2, revealing distinct stimulatory functions of CBC in mRNA export.

scholarly journals Separable functions of Tof1/Timeless in intra-S-checkpoint signalling, replisome stability and DNA topological stress

2020 ◽  
Vol 48 (21) ◽  
pp. 12169-12187
Author(s):  
Rose Westhorpe ◽  
Andrea Keszthelyi ◽  
Nicola E Minchell ◽  
David Jones ◽  
Jonathan Baxter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Replication Stress ◽  
Dna Helicase ◽  
The Other ◽  
Checkpoint Activation ◽  
Replication Checkpoint ◽  
Binding Partner ◽  
Dna Replication Checkpoint

Abstract The highly conserved Tof1/Timeless proteins minimise replication stress and promote normal DNA replication. They are required to mediate the DNA replication checkpoint (DRC), the stable pausing of forks at protein fork blocks, the coupling of DNA helicase and polymerase functions during replication stress (RS) and the preferential resolution of DNA topological stress ahead of the fork. Here we demonstrate that the roles of the Saccharomyces cerevisiae Timeless protein Tof1 in DRC signalling and resolution of DNA topological stress require distinct N and C terminal regions of the protein, whereas the other functions of Tof1 are closely linked to the stable interaction between Tof1 and its constitutive binding partner Csm3/Tipin. By separating the role of Tof1 in DRC from fork stabilisation and coupling, we show that Tof1 has distinct activities in checkpoint activation and replisome stability to ensure the viable completion of DNA replication following replication stress.

scholarly journals A Role for theSaccharomyces cerevisiaeRENT Complex Protein Net1 inHMRSilencing

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1411-1423
Author(s):  
Daniela Kasulke ◽  
Stefanie Seitz ◽  
Ann E Ehrenhofer-Murray
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein A ◽  
Rdna Locus ◽  
The Other ◽  
Central Component ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sir Proteins ◽  
Complex Protein ◽  
Subtelomeric Regions

AbstractSilencing in the yeast Saccharomyces cerevisiae is known in three classes of loci: in the silent mating-type loci HML and HMR, in subtelomeric regions, and in the highly repetitive rDNA locus, which resides in the nucleolus. rDNA silencing differs markedly from the other two classes of silencing in that it requires a DNA-associated protein complex termed RENT. The Net1 protein, a central component of RENT, is required for nucleolar integrity and the control of exit from mitosis. Another RENT component is the NAD+-dependent histone deacetylase Sir2, which is the only silencing factor known to be shared among the three classes of silencing. Here, we investigated the role of Net1 in HMR silencing. The mutation net1-1, as well as NET1 expression from a 2μ-plasmid, restored repression at silencing-defective HMR loci. Both effects were strictly dependent on the Sir proteins. We found overexpressed Net1 protein to be directly associated with the HMR-E silencer, suggesting that Net1 could interact with silencer binding proteins and recruit other silencing factors to the silencer. In agreement with this, Net1 provided ORC-dependent, Sir1-independent silencing when artificially tethered to the silencer. In contrast, our data suggested that net1-1 acted indirectly in HMR silencing by releasing Sir2 from the nucleolus, thus shifting the internal competition for Sir2 from the silenced loci toward HMR.

scholarly journals Comparative Activity of Six Recombinant Stilbene Synthases in Yeast for Resveratrol Production

2020 ◽  
Vol 10 (14) ◽  
pp. 4847
Author(s):  
Nemesio Villa-Ruano ◽  
Antonio Rivera ◽  
Efraín Rubio-Rosas ◽  
Gerardo Landeta-Cortés ◽  
Jenaro Leocadio Varela-Caselis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Batch Fermentation ◽  
Expression Vector ◽  
The Other ◽  
Acidic Ph ◽  
Polygonum Cuspidatum ◽  
Recombinant Yeast ◽  
Coumaric Acid ◽  
Comparative Activity

Resveratrol is a nutraceutical with relevant benefits to human health. This investigation reports on the generation and evaluation of six recombinant yeast lines that produce resveratrol from p-coumaric acid. The yeast lines contained a single p-coumaric acid-Co-A ligase from Plagiochasma appendiculatum combined with the stilbene synthases from Parthenocissus henryana, Polygonum cuspidatum, Morus alba var. atropurpurea, Rheum tataricum, Vitis vinifera and Arachis hypogaea. Codon optimized versions of these sequences were inserted in an expression vector flanked by the constitutive PGK and GPD promoters before expression in Saccharomyces cerevisiae. Batch fermentation (60 h) revealed that yeast lines had different capacities (p < 0.01) to produce resveratrol. Slightly acidic pH (6) and concentrations <100 mg L−1 p-coumaric acid improved resveratrol yields. Among the six lines, those containing the stilbene synthases (STS) from P. cuspidatum and M. alba produced up to 39 mg L−1 using 70 mg L−1 p-coumaric acid. On the other hand, lines expressing STS from V. vinifera, A. hypogaea and R. tataricum generated resveratrol faster than other lines but accumulated lower amounts at the end of the batch period (27–30 mg L−1). The simultaneous consumption of ethanol and p-coumaric acid corroborates the role of ethanol as a carbon source involved in the conversion of p-coumaric acid into resveratrol.

scholarly journals The origin of Brettanomyces bruxellensis in wines: a review

OENO One ◽  
2007 ◽  
Vol 41 (3) ◽  
pp. 161 ◽  
Author(s):  
Vincent Renouf ◽  
Aline Lonvaud-Funel ◽  
Joana Coulon
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Red Wine ◽  
Microbial Consortium ◽  
Yeast Species ◽  
The Other ◽  
Volatile Phenols ◽  
Brettanomyces Bruxellensis ◽  
Microbial Analysis ◽  
Key Steps

<p style="text-align: justify;"><strong>Aims</strong>: This work reviews the latest knowledge concerning the role of Brettanomyces bruxellensis in red wine alteration.</p><p style="text-align: justify;"><strong>Results and conclusion</strong>: The origin of this yeast species and its place in the wine microbial consortium are discussed as well as microbial equilibriums with the other species, notably Saccharomyces cerevisiae and lactic acid bacteria. As a consequence, fermentations are described as key steps in Brettanomyces development management. Furthermore, the influence of ageing through the use of traditional winemaking practices is explained.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: Finally, this paper emphases the need for a better understanding of chemical and microbial analysis together in order to better control this undesirable yeast and prevent the production of volatile phenols.</p>

scholarly journals Role of Doa1 in the Saccharomyces cerevisiae DNA Damage Response

2006 ◽  
Vol 26 (11) ◽  
pp. 4122-4133 ◽  
Author(s):  
Ewa T. Lis ◽  
Floyd E. Romesberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Dna Replication ◽  
Dna Damage Response ◽  
Cellular Response ◽  
Chromatin Modification ◽  
Degradation Pathway ◽  
Histone H2b ◽  
Damage Response

ABSTRACT The cellular response to DNA damage requires not only direct repair of the damage but also changes in the DNA replication machinery, chromatin, and transcription that facilitate survival. Here, we describe Saccharomyces cerevisiae Doa1, which helps to control the damage response by channeling ubiquitin from the proteosomal degradation pathway into pathways that mediate altered DNA replication and chromatin modification. DOA1 interacts with genes involved in PCNA ubiquitination, including RAD6, RAD18, RAD5, UBC13, and MMS2, as well as genes involved in histone H2B ubiquitination or deubiquitination, including RAD6, BRE1, LGE1, CDC73, UBP8, UBP10, and HTB2. In the absence of DOA1, damage-induced ubiquitination of PCNA does not occur. In addition, the level of ubiquitinated H2B is decreased under normal conditions and completely absent in the presence of DNA damage. In the case of PCNA, the defect associated with the doa1Δ mutant is alleviated by overexpression of ubiquitin, but in the case of H2B, it is not. The data suggest that Doa1 is the major source of ubiquitin for the DNA damage response and that Doa1 also plays an additional essential and more specific role in the monoubiquitination of histone H2B.

scholarly journals Separable functions of Tof1/Timeless in intra-S-checkpoint signalling, replisome stability and DNA topological stress

2019 ◽  
Author(s):  
Rose Westhorpe ◽  
Andrea Keszthelyi ◽  
Nicola E. Minchell ◽  
David Jones ◽  
Jonathan Baxter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Replication Stress ◽  
Dna Helicase ◽  
The Other ◽  
Checkpoint Activation ◽  
Replication Checkpoint ◽  
Binding Partner ◽  
Dna Replication Checkpoint

AbstractThe highly conserved Tof1/Timeless proteins minimise replication stress and promote normal DNA replication. They are required to mediate the DNA replication checkpoint (DRC), the stable pausing of forks at protein fork blocks, the coupling of DNA helicase and polymerase functions during replication stress (RS) and the preferential resolution of DNA topological stress ahead of the fork. Here we demonstrate that the roles of the Saccharomyces cerevisiae Timeless protein Tof1 in DRC signalling and resolution of DNA topological stress require distinct N and C terminal regions of the protein, whereas the other functions of Tof1 are closely linked to the stable interaction between Tof1 and its constitutive binding partner Csm3/Tipin. By separating the role of Tof1 in DRC from fork stabilisation and coupling, we show that Tof1 has distinct activities in checkpoint activation and replisome stability to ensure the viable completion of DNA replication following replication stress.

scholarly journals Monocyte Subsets in Schistosomiasis Patients with Periportal Fibrosis

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Jamille Souza Fernandes ◽  
Maria Ilma Araujo ◽  
Diego Mota Lopes ◽  
Robson da Paixão de Souza ◽  
Edgar M. Carvalho ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Protective Role ◽  
The Other ◽  
Monocyte Subsets ◽  
Periportal Fibrosis ◽  
Hla Dr ◽  
Low Levels ◽  
Classical Monocytes ◽  
Severe Fibrosis

A major issue withSchistosoma mansoniinfection is the development of periportal fibrosis, which is predominantly caused by the host immune response to egg antigens. Experimental studies have pointed to the participation of monocytes in the pathogenesis of liver fibrosis. The aim of this study was to characterize the subsets of monocytes in individuals with different degrees of periportal fibrosis secondary to schistosomiasis. Monocytes were classified into classical (CD14++CD16−), intermediate (CD14++CD16+), and nonclassical (CD14+CD16++). The expressions of monocyte markers and cytokines were assessed using flow cytometry. The frequency of classical monocytes was higher than the other subsets. The expression of HLA-DR, IL-6, TNF-α, and TGF-βwas higher in monocytes from individuals with moderate to severe fibrosis as compared to other groups. Although no differences were observed in receptors expression (IL-4R and IL-10R) between groups of patients, the expression of IL-12 was lower in monocytes from individuals with moderate to severe fibrosis, suggesting a protective role of this cytokine in the development of fibrosis. Our data support the hypothesis that the three different monocyte populations participate in the immunopathogenesis of periportal fibrosis, since they express high levels of proinflammatory and profibrotic cytokines and low levels of regulatory markers.

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