Biochemistry, Biophysics, and Structural Biology Commons^™

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. …

Cytoplasmic Polyadenylation Element Binding Protein 2 Alternative Splicing Regulates Hif1Α During Chronic Hypoxia, Emily M. Mayo

USF Tampa Graduate Theses and Dissertations

Chronic pulmonary hypoxia commonly results in the sustained expression of HIF1 (hypoxia inducible factor 1), a heterodimeric transcription factor, that, if unrestrained, can result in dramatic vasculature remodeling, pulmonary arterial hypertension, and right-sided heart failure. Together, these pulmonary disorders cost approximately $100 billion annually to treat due to the limited therapeutic targets designed to inhibit HIF1 expression. In this study, we introduce a translational regulator of HIF1 expression, known as Cytosolic polyadenylation element binding proteins 2 (CPEB2). Our lab has previously demonstrated in cancer cells that alternatively spliced isoforms of CPEB2 regulate the translation of the HIF1 oxygen-dependent subunit, HIF1α, …

Global Coordination Between Gene Expression Processes In C. Crescentus, James Raymond Aretakis

Wayne State University Dissertations

Gene expression is an essential process of all organisms which occurs in two steps, mRNA transcription, and translation and which is shut off by mRNA decay. For a bacterium to grow and divide, these steps need to be tuned to optimize the synthesis rates of thousands of proteins from their genes. Genome-wide experiments were used to determine the absolute transcription rates, mRNA degradation rates, and translation rates on a gene by gene basis in the model bacterium Caulobacter crescentus. This not only provides a system biology view of the organism’s gene expression resource allocation, but also provides a chance to …

Identification Of Ires Activity In Cellular Mrnas And Viral Rna Using A Circular Rna Construct, Priyanka Sehta

Legacy Theses & Dissertations (2009 - 2024)

Translation initiation is a critical step in the process of protein synthesis. The canonical way of translation initiation involves ribosomes being recruited to the 7-methyl guanosine cap present at the 5’end of the untranslated region (5’ UTR) of the RNAs. However, viral RNAs and some cellular mRNAs lack this 5’ cap structure and thus deploy an alternate non-canonical translation initiation mechanism. In non-canonical translation initiation, ribosome recruitment is facilitated by the RNA secondary structures called Internal Ribosome Entry Site (IRES) present most often in the 5’ UTR. To measure IRES-mediated translation, the dual luciferase assay has been the gold standard. …

Iojap: Morphological And Physiological Phenotype Characterization In Arabidopsis, Thomas Jay Payne

Doctoral Dissertations

IOJAP protein is found in all organisms that contain a ribosome of bacterial origin. The majority of studies suggest that IOJAP plays a role in translation, although this has yet to be thoroughly investigated in plants. Using Arabidopsis thaliana, an extensive phenotype characterization of iojap mutants was performed. Many processes of plant growth were slightly impaired at optimal temperature (22˚C) but became severely hindered at low temperature (12˚C and 4˚C). These cold temperature defects manifested in an overall reduction of plant growth as well as variegation, chlorosis, leaf hyponasty, as well as reduced maximum quantum yield (F_v/F …

Regulation Of Gene Expression Through Ribosome-Associated Proteins, Clare Margaret Miller

Legacy Theses & Dissertations (2009 - 2024)

Translation is a crucial mechanism for generating proteins to carry out cellular processes and for ensuring proper cell functions. Ribosomes are at the center of translation and are complex pieces of machinery. They consist of at least 80 core eukaryotic ribosomal proteins, which are conserved from prokaryotes, and four ribosomal RNAs (rRNAs): 18S, 28S, 5,8A 5S. In addition, numerous translation factors aid the ribosome in protein production. While ribosomes are typically described by these core features, they are known to exist in a heterogenous pool with variations in protein composition, modifications of rRNA, and an assortment of non-ribosomal proteins that …

The Impact Of Mrna Structure On Trna Selection And Ribosome Rescue, Erica Nicole Thomas

Arts & Sciences Electronic Theses and Dissertations

The faithful and rapid translation of proteins from genetic information is an essential feature of the ribosome. The general process of tRNA selection is governed by the ability of the ribosome to select for the aminoacylated tRNA (aa-tRNA) that matches the codon in its A-site. The efficiency and accuracy of this selection depends on the ability of nucleotides to form proper hydrogen bonds. While much is known about how chemical alterations of tRNA and rRNA can impact the fidelity of translation, less is known about how similar changes to mRNA affect decoding. In this work, we describe several studies aimed …

Rack1 Is A Critical Component In Ires-Mediated Translation, Ethan Asher Lafontaine

Legacy Theses & Dissertations (2009 - 2024)

Due to its sheer number of interacting partners, core ribosomal protein RACK1 is a key player in many cellular processes and has been shown to play a vital role of translation initiation of the Hepatitis C virus RNA. The HCV 5′ untranslated region contains an internal ribosome entry site. IRES-mediated translation is a process employed in eukaryotes by select viruses and some cellular mRNAs by which translation initiation bypasses the canonical mRNA cap-dependent pathway by means of an RNA secondary structure (the IRES). While cap-dependent translation requires the recruitment of a suite of initiation factors, IRES-mediated translation requires few to …

Regulation Of Gene Expression By Rna Binding Proteins And Micrornas, Kyle Cottrell

Arts & Sciences Electronic Theses and Dissertations

Regulation of gene expression is essential to life. Post-transcriptional regulation of gene expression is a complex process with many inputs that lead to changes in localization, translation and stability of mRNAs. The translation and stability of many mRNAs is regulated by cis-elements, such as mRNA-structure or codon optimality; and by trans-acting factors such as RBPs and miRNAs. Here I report on the complex interactions between RBPs, miRNAs and characteristics of their target mRNAs in respect to effects on translation and RNA stability.

Using a reporter based approach we studied modulation of microRNA-mediated repression by various mRNA characteristics. We observed the …

Mechanisms Of Regulation Of Tau Ires Mediated Translation, Niza Nemkul

Dissertations & Theses (Open Access)

The translation of most eukaryotic mRNAs occurs in a cap-dependent manner. However, a subset of mRNAs are capable of initiating translation in a cap-independent manner by utilizing sequences in their 5’ UTR called IRES. It was previously shown that the 5’ UTR of the tau mRNA contains an IRES. In this study I show that IRES dependent translation of tau IRES is regulated at multiple levels in order to regulate the expression of the tau protein.

Tau protein is ubiquitously expressed but is concentrated in the brain. In this study, I utilized neural and non-neural cell lines to show that …

The Role Of Trm9 In Stress Responses, Ashish Ravindra Patil

Legacy Theses & Dissertations (2009 - 2024)

Cells need to respond appropriately to environmental changes in order to maintain homeostasis. The cellular response to an environmental stress is regulated at transcriptional, translational and post translational levels. The tRNA, which acts as an adaptor molecule between the mRNA and the protein, plays an important role in the translational regulation of cellular responses to stress and is one of the most heavily modified biomolecules. In Saccharomyces cerevisiae , the wobble uracil of the tRNA(3'-UCU-5') Arg, tRNA(3'-UUC-5') Glu and certain other specific tRNAs are modified to 5-methoxycarbonylmethyluridine (mcm5U) and 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) residues by the tRNA methyltransferase 9 (Trm9). Modifications at …