Molecular Biology Commons^™

Dpc29 Promotes Post-Initiation Mitochondrial Translation In Saccharomyces Cerevisiae, Kyle A. Hubble, Michael F. Henry

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We …

Dpc29 Promotes Mitochondrial Translation Post-Initation In Saccharomyces Cerevisiae, Kyle Andrew Hubble

Graduate School of Biomedical Sciences Theses and Dissertations

Although the cytosolic and bacterial translation systems are well studied, much less is known about translation in mitochondria. In the yeast Saccharomyces cerevisiae, mitochondrial gene expression is predominately regulated by translational activators. These regulators are thought to promote translation by binding the elongated 5’-UTRs on their target mRNAs. Since mammalian mitochondrial mRNAs generally lack 5’-UTRs, they must regulate translation by other mechanisms. As expected, most yeast translational activators lack orthologues in mammals. Recently, a mitochondrial gene-specific translational activator, TACO1, was reported in mice and humans. To better define its role in mitochondrial translation I examined the yeast TACO1 orthologue, DPC29. …

Effects Of Trans-Acting Factors On The Translational Machinery In Yeast, Brandon M. Trainor

Graduate School of Biomedical Sciences Theses and Dissertations

Synthesis of proteins, or translation, is a complex biological process requiring the coordinated effort of numerous protein and RNA factors. Central to translation is the ribosome, a complex macromolecular complex consisting of both ribosomal RNA (rRNA) and ribosomal protein (r-protein). Ribosomes are essential and are one of the oldest and most abundant biomolecules across all forms of life. In addition to the ribosome, translation requires messenger RNA (mRNA), transfer-RNA conjugated to an amino acid (aa-tRNA), translation factors, and energy in the form of ATP and GTP. Translation universally occurs in four major stages, initiation, elongation, termination, and recycling, with initiation …

Retrotransposon-Mediated Transduction Of An Environmental Cue To Regulate Centrosome Fate, Shawn Patrick Murphy

Legacy Theses & Dissertations (2009 - 2024)

In 1969, the enrichment of mobile element repeat sequences led Britton and Davidson to propose the hypothesis that gene expression in higher eukaryotes is regulated through the exaptation of mobile elements. In this work, I have explored the hypothesis that mobile elements can also be harnessed by the host to regulate asymmetric cell division, thereby determining cell fate. Retrotransposons are ubiquitous eukaryotic mobile elements that transpose through an RNA intermediate. They are often active in cell types that divide asymmetrically to yield daughter cells with different fates, such as embryonic stem cells, germline stem cells, neuronal stem cells and the …

Acetic Acid Induces Sch9p-Dependent Translocation Of Isc1p From The Endoplasmic Reticulum Into Mitochondria, António Rego, Katrina F Cooper, Justin Snider, Yusuf A Hannun, Vítor Costa, Manuela Côrte-Real, Susana R Chaves

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Changes in sphingolipid metabolism have been linked to modulation of cell fate in both yeast and mammalian cells. We previously assessed the role of sphingolipids in cell death regulation using a well characterized yeast model of acetic acid-induced regulated cell death, finding that Isc1p, inositol phosphosphingolipid phospholipase C, plays a pro-death role in this process. Indeed, isc1∆ mutants exhibited a higher resistance to acetic acid associated with reduced mitochondrial alterations. Here, we show that Isc1p is regulated by Sch9p under acetic acid stress, since both single and double mutants lacking Isc1p or/and Sch9p have the same resistant phenotype, and SCH9 …

The Role Of The Mediator Transcriptional Co-Activator Complex And Promoter Dependence In Ty1 Retrotransposition In Saccharomyces Cerevisiae, Alicia Salinero

Legacy Theses & Dissertations (2009 - 2024)

Retrotransposons are mobile genetic elements that replicate via an RNA intermediary and constitute a significant portion of most eukaryotic genomes. Saccharomyces cerevisiae has been invaluable to retrotransposon research due to the presence of an active retroelement known as Ty1. The mobility of Ty1 is regulated both positively and negatively by numerous host factors, including several subunits of the Mediator transcriptional co-activator complex. The Mediator core complex is organized into genetically and structurally defined head, middle, and tail modules, along with a transiently associated kinase module. We show that with the exception of the kinase module, deletion of non-essential subunits from …

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 …

Med13p Prevents Stress-Independent Mitochondrial Hyperfragmentation And Aberrant Apoptosis Activation In Saccharomyces Cerevisiae By Controlling Cyclin C Nuclear Localization, Svetlana Khakhina

Graduate School of Biomedical Sciences Theses and Dissertations

During aging, and as a result of environmental changes, cells are exposed to elevated levels of reactive oxygen species (ROS). High ROS levels induce lipid oxidation, protein aggregation, mitochondrial hyperfragmentation, DNA damage and programmed cell death (PCD), also called apoptosis. PCD is a highly regulated process and its misregulation has been linked to neurodegenerative diseases and cancer development.

Our hypothesis is that cyclin C plays a role in the initiation of apoptosis. During normal conditions, cyclin C represses the transcription of stress response genes (SRG). In response to stress, cyclin C translocates to the cytoplasm where it facilitates mitochondrial hyperfragmentation …

The Role Of Chromatin And Cofactors In The Transcriptional Memory Effect Exerted In Saccharomyces Cerevisiae, Emily Leigh Paul

Legacy Theses & Dissertations (2009 - 2024)

Abf1 and Rap1 are functionally similar general regulatory factors (GRFs) found in Saccharomyces cerevisiae . Abf1, in its role as a transcriptional activator, exerts a memory effect on some genes under its control. This effect results in transcription levels remaining steady when Abf1 dissociates from its binding site in a conditional mutant. In contrast, Rap1 fails to elicit the same effect on its regulatory targets. Transcriptional memory effects have been observed in many fields of study, including immunology, cancer, and stem cells, and conservation of transcription machinery will allow studies in yeast to be applied to higher organisms.

Quantifying And Resolving Multiple Vector Transformants In S. Cerevisiae Plasmid Libraries, Thomas C. Scanlon, Elizabeth C. Gray, Karl E. Griswold

Dartmouth Scholarship

In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the …

The Cell Cycle–Regulated Genes Of Schizosaccharomyces Pombe, Anna Oliva, Adan Rosebrock, Francisco Ferrezuelo, Haiying Chen, Saumyadipta Pyne, Steve Skiena, Bruce Futcher, Janet Leatherwood

Department of Molecular Genetics and Microbiology Faculty Publications

Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 …