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Saccharomyces cerevisiae

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Articles 1 - 30 of 53

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Crossover Recombination And Synapsis Are Linked By Adjacent Regions Within The N Terminus Of The Zip1 Synaptonemal Complex Protein, Karen Voelkel-Meiman, Shun-Yun Cheng, Melanie Parziale, Savannah J. Morehouse, Arden Feil, Owen R. Davies, Arnaud De Muyt, Valerie Borde, Amy J. Macqueen Jun 2019

Crossover Recombination And Synapsis Are Linked By Adjacent Regions Within The N Terminus Of The Zip1 Synaptonemal Complex Protein, Karen Voelkel-Meiman, Shun-Yun Cheng, Melanie Parziale, Savannah J. Morehouse, Arden Feil, Owen R. Davies, Arnaud De Muyt, Valerie Borde, Amy J. Macqueen

Open Access Articles

Accurate chromosome segregation during meiosis relies on the prior establishment of at least one crossover recombination event between homologous chromosomes. Most meiotic recombination intermediates that give rise to interhomolog crossovers are embedded within a hallmark chromosomal structure called the synaptonemal complex (SC), but the mechanisms that coordinate the processes of SC assembly (synapsis) and crossover recombination remain poorly understood. Among known structural components of the budding yeast SC, the Zip1 protein is unique for its independent role in promoting crossover recombination; Zip1 is specifically required for the large subset of crossovers that also rely on the meiosis-specific MutSgamma complex. Here ...


Transfer Rna Genes Affect Chromosome Structure And Function Via Local Effects, Omar Hamdani, Tsung-Han S. Hsieh, Oliver J. Rando, Rohinton T. Kamakaka Apr 2019

Transfer Rna Genes Affect Chromosome Structure And Function Via Local Effects, Omar Hamdani, Tsung-Han S. Hsieh, Oliver J. Rando, Rohinton T. Kamakaka

Open Access Articles

The genome is packaged and organized in an ordered, non-random manner and specific chromatin segments contact nuclear substructures to mediate this organization. Transfer RNA genes (tDNAs) are binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the role of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacks any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromatin architecture or chromosome tethering and mobility. However, loss of ...


N-Terminal Sumoylation Of Centromeric Histone H3 Variant Cse4 Regulates Its Proteolysis To Prevent Mislocalization To Non-Centromeric Chromatin, Kentaro Ohkuni, Reuben Levy-Myers, Jack Warren, Wei-Chun Au, Yoshimitsu Takahashi, Richard E. Baker, Munira A. Basrai Mar 2018

N-Terminal Sumoylation Of Centromeric Histone H3 Variant Cse4 Regulates Its Proteolysis To Prevent Mislocalization To Non-Centromeric Chromatin, Kentaro Ohkuni, Reuben Levy-Myers, Jack Warren, Wei-Chun Au, Yoshimitsu Takahashi, Richard E. Baker, Munira A. Basrai

Open Access Articles

Stringent regulation of cellular levels of evolutionarily conserved centromeric histone H3 variant (CENP-A in humans, CID in flies, Cse4 in yeast) prevents its mislocalization to non-centromeric chromatin. Overexpression and mislocalization of CENP-A has been observed in cancers and leads to aneuploidy in yeast, flies, and human cells. Ubiquitin-mediated proteolysis of Cse4 by E3 ligases such as Psh1 and Sumo-Targeted Ubiquitin Ligase (STUbL) Slx5 prevent mislocalization of Cse4. Previously, we identified Siz1 and Siz2 as the major E3 ligases for sumoylation of Cse4. In this study, we have identified lysine 65 (K65) in Cse4 as a site that regulates sumoylation and ...


Sumo Targeting Of A Stress-Tolerant Ulp1 Sumo Protease, Jennifer Peek, Catherine Harvey, Dreux Gray, Danny Rosenberg, Likhitha Kolla, Reuben Levy-Myers, Rui Yin, Oliver Kerscher, Jonathan L. Mcmurry Jan 2018

Sumo Targeting Of A Stress-Tolerant Ulp1 Sumo Protease, Jennifer Peek, Catherine Harvey, Dreux Gray, Danny Rosenberg, Likhitha Kolla, Reuben Levy-Myers, Rui Yin, Oliver Kerscher, Jonathan L. Mcmurry

Faculty Publications

SUMO proteases of the SENP/Ulp family are master regulators of both sumoylation and desumoylation and regulate SUMO homeostasis in eukaryotic cells. SUMO conjugates rapidly increase in response to cellular stress, including nutrient starvation, hypoxia, osmotic stress, DNA damage, heat shock, and other proteotoxic stressors. Nevertheless, little is known about the regulation and targeting of SUMO proteases during stress. To this end we have undertaken a detailed comparison of the SUMO-binding activity of the budding yeast protein Ulp1 (ScUlp1) and its ortholog in the thermotolerant yeast Kluyveromyces marxianus, KmUlp1. We find that the catalytic UD domains of both ScUlp1 and ...


Determining The Role Of Epigenetic Factors In Antifungal Drug Resistance, Abigail R. Gress, Scott D. Briggs, Nina Serratore Aug 2017

Determining The Role Of Epigenetic Factors In Antifungal Drug Resistance, Abigail R. Gress, Scott D. Briggs, Nina Serratore

The Summer Undergraduate Research Fellowship (SURF) Symposium

Epigenetic factors are proteins that regulate gene expression by altering transcriptional machinery access to nucleosomes, DNA wrapped around histone proteins. Two classes of epigenetic factors are ATP-dependent chromatin remodelers and histone modifiers such as histone methyltransferases (HMTs), proteins that add methyl groups to histone tails. This study focuses on AIF4 (Antifungal-Induced Factor 4), a possible HMT induced upon neutral lipid depletion that we hypothesize is regulating antifungal drug resistance genes. Overexpression of AIF4 results in hypersensitivity to antifungal drugs. Studying epigenetic factors in the yeast Saccharomyces cerevisiae, including AIF4, can lead to better understanding of cell adaptation to their environments ...


Negative Regulation Of Haa1 By Casein Kinase I Protein Hrr25 In Saccharomyces Cerevisiae, Morgan Collins May 2017

Negative Regulation Of Haa1 By Casein Kinase I Protein Hrr25 In Saccharomyces Cerevisiae, Morgan Collins

University of New Orleans Theses and Dissertations

Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. How Haa1 is activated by weak acids is not clear. This study proposes that Hrr25 is an important regulator of cellular adaptation to weak acid stress by inhibiting Haa1 through phosphorylation. YRO2, one of the targets of Haa1, shows increase in expression during stationary phase. This increase is due to basal activity of Haa1 and another, unknown, transcription factor. This study proposes that Gsm1 is another transcription factor that regulates YRO2 expression in the stationary phase. Finally, the ...


Using Rb-Tnseq To Analyze Natural Variation In Saccharomyces Cerevisiae, Syed Raza Mahmood May 2017

Using Rb-Tnseq To Analyze Natural Variation In Saccharomyces Cerevisiae, Syed Raza Mahmood

Theses and Dissertations

One of the main challenges in biology today is the characterization of millions of genes of unknown function being continuously identified in sequencing studies. Transposon mutagenesis is a technique that has been widely used for annotating gene function and has now been combined with next-generation sequencing (Tn-Seq) to assess mutant fitness on a genome wide basis. However, Tn-Seq approaches are often constrained by laborious library preparation protocols which limit the number of organisms or conditions that can be assessed. Random bar code transposon-site sequencing (RB-TnSeq), is a transposon sequencing technique that streamlines library preparation and increases the throughput of mutant ...


In Silico Driven Metabolic Engineering Towards Enhancing Biofuel And Biochemical Production, Richard Adam Thompson May 2016

In Silico Driven Metabolic Engineering Towards Enhancing Biofuel And Biochemical Production, Richard Adam Thompson

Doctoral Dissertations

The development of a secure and sustainable energy economy is likely to require the production of fuels and commodity chemicals in a renewable manner. There has been renewed interest in biological commodity chemical production recently, in particular focusing on non-edible feedstocks. The fields of metabolic engineering and synthetic biology have arisen in the past 20 years to address the challenge of chemical production from biological feedstocks. Metabolic modeling is a powerful tool for studying the metabolism of an organism and predicting the effects of metabolic engineering strategies. Various techniques have been developed for modeling cellular metabolism, with the underlying principle ...


Regulation Of Chaperone Binding And Nucleosome Dynamics By Key Residues Within The Globular Domain Of Histone H3, Sarah J. Hainer, Joseph A. Martens Apr 2016

Regulation Of Chaperone Binding And Nucleosome Dynamics By Key Residues Within The Globular Domain Of Histone H3, Sarah J. Hainer, Joseph A. Martens

Open Access Articles

BACKGROUND: Nucleosomes have an important role in modulating access of DNA by regulatory factors. The role specific histone residues have in this process has been shown to be an important mechanism of transcription regulation. Previously, we identified eight amino acids in histones H3 and H4 that are required for nucleosome occupancy over highly transcribed regions of the genome.

RESULTS: We investigate the mechanism through which three of these previously identified histone H3 amino acids regulate nucleosome architecture. We find that histone H3 K122, Q120, and R49 are required for Spt2, Spt6, and Spt16 occupancies at genomic locations where transcription rates ...


Investigating The Architecture And Vesicle Tethering Function Of The Yeast Exocyst Complex: A Dissertation, Margaret R. Heider Jan 2016

Investigating The Architecture And Vesicle Tethering Function Of The Yeast Exocyst Complex: A Dissertation, Margaret R. Heider

GSBS Dissertations and Theses

The exocyst is an evolutionarily conserved, hetero-octameric protein complex proposed to serve as a multi-subunit tethering complex for exocytosis, although it remains poorly understood at the molecular level. The classification of the exocyst as a multisubunit tethering complex (MTC) stems from its known interacting partners, polarized localization at the plasma membrane, and structural homology to other putative MTCs. The presence of 8 subunits begs the questions: why are so many subunits required for vesicle tethering and what are the contributions of each of these subunits to the overall structure of the complex? Additionally, are subunit or subcomplex dynamics a required ...


Characterization Of The Yeast Cysteine Desulfurase Complex Within The Mitochondrial Fe-S Cluster Biogenesis, Dulmini Pabasara Barupala Jan 2016

Characterization Of The Yeast Cysteine Desulfurase Complex Within The Mitochondrial Fe-S Cluster Biogenesis, Dulmini Pabasara Barupala

Wayne State University Dissertations

Disrupted iron homeostasis within the human body materializes as various disorders. Pathophysiology of many of them relates to iron induced oxidative damage to key cellular components caused by iron accumulation within the tissues. Pertaining to the growing occurrence, cost of patient care and devastating burden associated with these diseases, the call for understanding the role of iron homeostasis within these disorders becomes inevitable. Being an abundant iron containing cofactor, the role of Fe-S clusters in cellular iron homeostasis is indisputable in the case of Friedreich’s ataxia, a disease caused by a deficiency in the protein frataxin that is indispensable ...


In Vivo Single-Particle Imaging Of Nuclear Mrna Export In Budding Yeast Demonstrates An Essential Role For Mex67p, Carlas Smith, Azra Lari, Carina Patrizia. Derrer, Anette Ouwehand, Ammeret Rossouw, Maximiliaan Huisman, Thomas Dange, Mark Hopman, Aviva Joseph, Daniel Zenklusen, Karsten Weis, David Grünwald, Ben Montpetit Dec 2015

In Vivo Single-Particle Imaging Of Nuclear Mrna Export In Budding Yeast Demonstrates An Essential Role For Mex67p, Carlas Smith, Azra Lari, Carina Patrizia. Derrer, Anette Ouwehand, Ammeret Rossouw, Maximiliaan Huisman, Thomas Dange, Mark Hopman, Aviva Joseph, Daniel Zenklusen, Karsten Weis, David Grünwald, Ben Montpetit

RNA Therapeutics Institute Publications

Many messenger RNA export proteins have been identified; yet the spatial and temporal activities of these proteins and how they determine directionality of messenger ribonucleoprotein (mRNP) complex export from the nucleus remain largely undefined. Here, the bacteriophage PP7 RNA-labeling system was used in Saccharomyces cerevisiae to follow single-particle mRNP export events with high spatial precision and temporal resolution. These data reveal that mRNP export, consisting of nuclear docking, transport, and cytoplasmic release from a nuclear pore complex (NPC), is fast ( approximately 200 ms) and that upon arrival in the cytoplasm, mRNPs are frequently confined near the nuclear envelope. Mex67p functions ...


The Shape Of Silence: The Solution-State Conformation Of Sir Heterochromatin: A Dissertation, Sarah G. Swygert Aug 2015

The Shape Of Silence: The Solution-State Conformation Of Sir Heterochromatin: A Dissertation, Sarah G. Swygert

GSBS Dissertations and Theses

Heterochromatin is a silenced chromatin region essential for maintaining genomic stability in eukaryotes and for driving developmental processes in higher organisms. A hallmark of heterochromatin is the presence of specialized architectural proteins that alter chromatin structure to inhibit transcription and recombination. Although it is generally assumed that heterochromatin is highly condensed, surprisingly little is known about the structure of heterochromatin or its dynamics in solution. In budding yeast, heterochromatin assembly at telomeres and the HM silent mating type loci requires the Sir proteins: Sir3, believed to be the major structural component of SIR heterochromatin, and the Sir2/4 complex, responsible ...


Characterizing The Role Of Aif4 In Saccharomyces Cerevisiae, Antonia L. Hur Ms., Nina Serratore Ms., Scott D. Briggs Aug 2015

Characterizing The Role Of Aif4 In Saccharomyces Cerevisiae, Antonia L. Hur Ms., Nina Serratore Ms., Scott D. Briggs

The Summer Undergraduate Research Fellowship (SURF) Symposium

Chromatin remodelers are important regulatory mechanisms that eukaryotic cells use to modify the structure of chromatin, which is made up of DNA and proteins. DNA wraps around histone proteins to make up chromatin. When these proteins are modified, the shape of the chromatin is altered. “Loosening” the chromatin structure by chromatin modifications allows for active gene expression whereas “tightening” or compaction of chromatin results in gene repression. Therefore the modifications on chromatin modulate gene expression in all eukaryotes. It has been shown that mis-regulation of chromatin remodelers contribute to various cancers. Understanding the biochemistry behind how chromatin associating proteins modify ...


Dissecting Cis And Trans Determinants Of Nucleosome Positioning: A Dissertation, Amanda L. Hughes Nov 2014

Dissecting Cis And Trans Determinants Of Nucleosome Positioning: A Dissertation, Amanda L. Hughes

GSBS Dissertations and Theses

Eukaryotic DNA is packaged in chromatin, whose repeating subunit, the nucleosome, consists of an octamer of histone proteins wrapped by about 147bp of DNA. This packaging affects the accessibility of DNA and hence any process that occurs on DNA, such as replication, repair, and transcription. An early observation from genome-wide nucleosome mapping in yeast was that genes had a surprisingly characteristic structure, which has motivated studies to understand what determines this architecture. Both sequence and trans acting factors are known to influence chromatin packaging, but the relative contributions of cis and trans determinants of nucleosome positioning is debated. Here we ...


Energy Stress Causes Chaperones To Assemble Into Cytoplasmic Complexes, Kimberly J. Cope Aug 2014

Energy Stress Causes Chaperones To Assemble Into Cytoplasmic Complexes, Kimberly J. Cope

UT GSBS Dissertations and Theses (Open Access)

The majority of proteins require molecular chaperones to assist their folding into tertiary and quaternary structures. Certain stresses can compromise the weak hydrophobic forces responsible for these structures and lead to protein unfolding, misfolding, and aggregation. Aggregates of proteins are hallmarks of devastating diseases such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. Fortunately, bacteria, plants, and fungi have a potent disaggregase, named Hsp104 in Saccharomyces cerevisiae. Recently, heat-induced aggregates, termed Q-bodies, were found to contain three molecular chaperones: Hsp70, Hsp104, and Hsp42. Their coalescence from small puncta into larger inclusions required Hsp104. During glucose deprivation, a stress that ...


Identification Of Set1 Target Genes, William Beyer, Scott D. Briggs Oct 2013

Identification Of Set1 Target Genes, William Beyer, Scott D. Briggs

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Set1 complex, a histone methyltransferase complex found in S. cerevisiae (budding yeast), is the only histone methyltransferase responsible for catalyzing methylation of histone H3 at Lysine 4. It possesses homologues in other species, humans included. While yeast only have the Set1 complex, the human homologues of the yeast Set1 complex include mixed-lineage leukemia family (MLL1-4), Set1 A, Set1 B, among others. MLL1-4 has been shown to play a role in transcription, cell type specification, and the development of leukemia. One application of characterizing the role of a protein is that the information gained can provide insight into the function ...


Modeling Biochemical Processes As Designed Systems, Steven M. Gollmer Aug 2013

Modeling Biochemical Processes As Designed Systems, Steven M. Gollmer

Steven M. Gollmer, Ph.D.

Being in the post-genomic era, there is a need for new methodologies from an interdisciplinary perspective, which can complement current genomics research. Bioinformatics and systems biology are rapidly growing research areas that are meeting this need. Operating with the assumption that there is design with a purpose, creationists provide a unique perspective for discovering order in the complexity of genes, regulatory networks, and biochemical reactions.

Since the genome acts as an information storage system, it seems reasonable to apply design concepts, originating from computer and network programming, to make sense of genomic information. One such concept is that of design ...


Translocation Channel Gating Kinetics Balances Protein Translocation Efficiency With Signal Sequence Recognition Fidelity, Steven Trueman, Elisabet Mandon, Reid Gilmore Jul 2013

Translocation Channel Gating Kinetics Balances Protein Translocation Efficiency With Signal Sequence Recognition Fidelity, Steven Trueman, Elisabet Mandon, Reid Gilmore

Elisabet Mandon

The transition between the closed and open conformations of the Sec61 complex permits nascent protein insertion into the translocation channel. A critical event in this structural transition is the opening of the lateral translocon gate that is formed by four transmembrane (TM) spans (TM2, TM3, TM7, and TM8 in Sec61p) to expose the signal sequence-binding site. To gain mechanistic insight into lateral gate opening, mutations were introduced into a lumenal loop (L7) that connects TM7 and TM8. The sec61 L7 mutants were found to have defects in both the posttranslational and cotranslational translocation pathways due to a kinetic delay in ...


Investigation Of Multiple Concerted Mechanisms Underlying Stimulus-Induced G1 Arrest In Yeast: A Dissertation, Patricia A. Pope Jun 2013

Investigation Of Multiple Concerted Mechanisms Underlying Stimulus-Induced G1 Arrest In Yeast: A Dissertation, Patricia A. Pope

GSBS Dissertations and Theses

Progression through the cell cycle is tightly controlled, and the decision whether or not to enter a new cell cycle can be influenced by both internal and external cues. For budding yeast one such external cue is pheromone treatment, which can induce G1 arrest. Two distinct mechanisms are known to be involved in this arrest, one dependent on the arrest protein Far1 and one independent of Far1, but the exact mechanisms have remained enigmatic. The studies presented here further elucidate both of these mechanisms.

We looked at two distinct aspects of the Far1-independent arrest mechanism. First, we studied the role ...


Wax Ester Biosynthetic Pathway, Daolin Cheng Jan 2013

Wax Ester Biosynthetic Pathway, Daolin Cheng

Graduate Theses and Dissertations

Wax esters occur widely among bacteria, plants and mammals. Due to their special properties, they have many applications such as lubricants, cosmetics, pharmaceutical products, ink, polishes and candles. They are also considered as potential biofuels and biolubricants in the future. Wax ester producing enzymes synthesize wax esters from alcohols and fatty acyl coenzyme A thioesters. There are three gene families encoding enzymes capable of synthesizing wax esters. Two of them exist in plans; the jojoba-like wax synthase (WS), and the bifunctional wax synthase/diacylglycerol acyl transferase (WS/DGAT). We investigated the phylogenetic relationships among and between WS and WS/DGAT ...


Engineering Novel Terpene Production Platforms In The Yeast Saccharomyces Cerevisiae, Xun Zhuang Jan 2013

Engineering Novel Terpene Production Platforms In The Yeast Saccharomyces Cerevisiae, Xun Zhuang

Theses and Dissertations--Plant and Soil Sciences

The chemical diversity and biological activities of terpene and terpenoids have served in the development of new flavors, fragrances, medicines and pesticides. While terpenes are made predominantly by plants and microbes in small amounts and as components of complex mixtures, chemical synthesis of terpenes remains technically challenging, costly and inefficient. In this dissertation, methods to create new yeast lines possessing a dispensable mevalonate biosynthetic pathway wherein carbon flux can be diverted to build any chemical class of terpene product are described. The ability of this line to generate diterpenes was next investigated. Using a 5.5 L fed bath fermentation ...


Insights Into Mrnp Biogenesis Provided By New Genetic Interactions Among Export And Transcription Factors, Francisco Estruch, Christine Hodge, Natalia Gómez-Navarro, Lorena Peiró-Chova, Catherine V. Heath, Charles N. Cole Sep 2012

Insights Into Mrnp Biogenesis Provided By New Genetic Interactions Among Export And Transcription Factors, Francisco Estruch, Christine Hodge, Natalia Gómez-Navarro, Lorena Peiró-Chova, Catherine V. Heath, Charles N. Cole

Open Dartmouth: Faculty Open Access Scholarship

The various steps of mRNP biogenesis (transcription, processing and export) are interconnected. It has been shown that the transcription machinery plays a pivotal role in mRNP assembly, since several mRNA export factors are recruited during transcription and physically interact with components of the transcription machinery. Although the shuttling DEAD-box protein Dbp5p is concentrated on the cytoplasmic fibrils of the NPC, previous studies demonstrated that it interacts physically and genetically with factors involved in transcription initiation. We investigated the effect of mutations affecting various components of the transcription initiation apparatus on the phenotypes of mRNA export mutant strains. Our results show ...


Accelerated Maximum Likelihood Parameter Estimation For Stochastic Biochemical Systems, Bernie J. Daigle Jr., Min K. Roh, Linda R. Petzold, Jarad Niemi May 2012

Accelerated Maximum Likelihood Parameter Estimation For Stochastic Biochemical Systems, Bernie J. Daigle Jr., Min K. Roh, Linda R. Petzold, Jarad Niemi

Statistics Publications

Background: A prerequisite for the mechanistic simulation of a biochemical system is detailed knowledge of its kinetic parameters. Despite recent experimental advances, the estimation of unknown parameter values from observed data is still a bottleneck for obtaining accurate simulation results. Many methods exist for parameter estimation in deterministic biochemical systems; methods for discrete stochastic systems are less well developed. Given the probabilistic nature of stochastic biochemical models, a natural approach is to choose parameter values that maximize the probability of the observed data with respect to the unknown parameters, a.k.a. the maximum likelihood parameter estimates (MLEs). MLE computation ...


Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet Mandon, Alex Hausler, Kelley Moremen, Carlos Hirschberg, Phillips Robbins Feb 2012

Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet Mandon, Alex Hausler, Kelley Moremen, Carlos Hirschberg, Phillips Robbins

Elisabet Mandon

Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn ...


Down-Regulating Sphingolipid Synthesis Increases Yeast Lifespan, Xinhe Huang, Jun Liu, Robert C. Dickson Feb 2012

Down-Regulating Sphingolipid Synthesis Increases Yeast Lifespan, Xinhe Huang, Jun Liu, Robert C. Dickson

Molecular and Cellular Biochemistry Faculty Publications

Knowledge of the mechanisms for regulating lifespan is advancing rapidly, but lifespan is a complex phenotype and new features are likely to be identified. Here we reveal a novel approach for regulating lifespan. Using a genetic or a pharmacological strategy to lower the rate of sphingolipid synthesis, we show that Saccharomyces cerevisiae cells live longer. The longer lifespan is due in part to a reduction in Sch9 protein kinase activity and a consequent reduction in chromosomal mutations and rearrangements and increased stress resistance. Longer lifespan also arises in ways that are independent of Sch9 or caloric restriction, and we speculate ...


Insights Into Er Translocation Channel Gating. Structural Regulation Of The Transition Between The Closed And Open Channel Conformations: A Dissertation, Steven F. Trueman Oct 2011

Insights Into Er Translocation Channel Gating. Structural Regulation Of The Transition Between The Closed And Open Channel Conformations: A Dissertation, Steven F. Trueman

GSBS Dissertations and Theses

The transition between the closed and open conformations of the Sec61 complex permits nascent protein insertion into the translocation channel. A critical event in this structural transition is the opening of the lateral translocon gate that is formed by four transmembrane (TM) spans (TM2, TM3, TM7 and TM8 in Sec61p) to expose the signal sequence-binding (SSB) site. To gain mechanistic insight into lateral gate opening, mutations were introduced into a lumenal loop (L7) that connects TM7 and TM8. The sec61 L7 mutants were found to have defects in both the posttranslational and cotranslational translocation pathways due to a kinetic delay ...


A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun Oct 2011

A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun

Open Dartmouth: Faculty Open Access Scholarship

Intracellular membrane fusion requires R-SNAREs and Q-SNAREs to assemble into a four-helical parallel coiled-coil, with their hydrophobic anchors spanning the two apposed membranes. Based on the fusion properties of chemically defined SNARE- proteoliposomes, it has been proposed that the assembly of this helical bundle transduces force through the entire bilayer via the transmembrane SNARE anchor domains to drive fusion. However, an R-SNARE, Nyv1p, with a genetically engineered lipid anchor that spans half of the bilayer suffices for the fusion of isolated vacuoles, although this organelle has other R-SNAREs. To demonstrate unequivocally the fusion activity of lipid-anchored Nyv1p, we reconstituted proteoliposomes ...


The Mitospecific Region Of Mrp20 And Its Importance For The Assembly Of Mitochondrial Ribosomes In Saccharomyces Cerevisiae, Jasvinder Kaur Jul 2011

The Mitospecific Region Of Mrp20 And Its Importance For The Assembly Of Mitochondrial Ribosomes In Saccharomyces Cerevisiae, Jasvinder Kaur

Dissertations (2009 -)

Yeast mitochondrial ribosomes are composed of an rRNA scaffold, encoded by the mitochondrial genome and many different proteins, which, with the exception of one, are encoded by nuclear genes. These ribosomal proteins are imported into the mitochondrial matrix following their synthesis in the cytosol, however, little is known about the subsequent events which result in an assembled, translationally-competent ribosome. Many of the mitochondrial ribosomal proteins bear homology to bacterial ancestors. In addition to the acquisition of mitochondrial targeting signals, a number of these nuclearly-encoded ribosomal proteins have acquired additional domains, often at their C-termini, which are termed "mitochondrial-specific domains". The ...


Systematic Two-Hybrid And Comparative Proteomic Analyses Reveal Novel Yeast Pre-Mrna Splicing Factors Connected To Prp19, Liping Ren, Janel R. Mclean, Tony R. Hazbun, Stanley Fields, Craig Vander Kooi, Melanie D. Ohi, Kathleen L. Gould Feb 2011

Systematic Two-Hybrid And Comparative Proteomic Analyses Reveal Novel Yeast Pre-Mrna Splicing Factors Connected To Prp19, Liping Ren, Janel R. Mclean, Tony R. Hazbun, Stanley Fields, Craig Vander Kooi, Melanie D. Ohi, Kathleen L. Gould

Molecular and Cellular Biochemistry Faculty Publications

Prp19 is the founding member of the NineTeen Complex, or NTC, which is a spliceosomal subcomplex essential for spliceosome activation. To define Prp19 connectivity and dynamic protein interactions within the spliceosome, we systematically queried the Saccharomyces cerevisiae proteome for Prp19 WD40 domain interaction partners by two-hybrid analysis. We report that in addition to S. cerevisiae Cwc2, the splicing factor Prp17 binds directly to the Prp19 WD40 domain in a 1:1 ratio. Prp17 binds simultaneously with Cwc2 indicating that it is part of the core NTC complex. We also find that the previously uncharacterized protein Urn1 (Dre4 in Schizosaccharomyces pombe ...