Biochemistry Commons^™

Structure And Function Of Coding And Non-Coding Rna Domains, Fei Liu

Legacy Theses & Dissertations (2009 - 2024)

As a versatile molecule, RNA exhibits an astonishing variety of functional activities, which is typically attributed to its particular structure-forming capacity. There are an increasing number of established roles and systems where RNA structures, in particular, RNA pseudoknots, affect specific biological processes based on their structural features. The structure-function-relationships of RNA in three systems has been invesgated: the telomerase RNA pseudoknot domain from S. cerevisiae, a poteintial unusual H-type pseudoknot forming region near the 3'-splice-site in the influenza virus NS1 mRNA, and the 5'-untranslated-region of the CC16 mRNA where mutations in the wildtype sequence have been related to asthma. UV-monitored …

Design And Application Of Composite Rna Aptamers, Shengchun Wang

Legacy Theses & Dissertations (2009 - 2024)

aptamers are being developed as an essential tool in many fields of biological research. Their utility is not limited to being protein inhibitors; a lot of novel functions can be realized. However, in vivo application of RNA aptamers still faces many challenges. The aim of this dissertation is to design and apply composite aptamers in multiple expression and delivery systems to address some critical issues, such as correct folding, high level production, degradation by nucleases, excessive consumption of cellular resource and potential toxic effect.

Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Trm5 is a eukaryal and archaeal tRNA methyltransferase that catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to the N(1) position of G37 directly 3' to the anticodon. While the biological role of m(1)G37 in enhancing translational fidelity is well established, the catalytic mechanism of Trm5 has remained obscure. To address the mechanism of Trm5 and more broadly the mechanism of N-methylation to nucleobases, we examined the pH-activity profile of an archaeal Trm5 enzyme, and performed structure-guided mutational analysis. The data reveal a marked dependence of enzyme-catalyzed methyl transfer on hydrogen ion equilibria: the single-turnover rate constant for methylation increases by one …

Synthesis Of 2,4,5-Triaminocyclohexane Carboxylic Acid As A Novel 2-Deoxystreptamine Mimetic, Sarah Elizabeth Roberts

Theses and Dissertations

RNAs have become increasingly recognized as possible drug targets due to their involvement in important biochemical functions, as well as their unique but well-defined structures. Recently published crystal structures depict the binding of a series of aminoglycosides- or more specifically- 2-deoxystretamine (2-DOS), the most preserved central scaffold of aminoglycosides, to a conserved 5'-GU-3'region on their target RNAs. A novel unnatural γ-amino acid, 1, has been synthesized using 2-deoxystreptamine as a template through structure-based rational design. The unnatural amino acid has been designed to replace a glycosidic linkage with an amide bond, which may limit the promiscuous binding characteristics of aminoglycosides …

Secondary Structures And Thermodynamic Properties Of Ampa Receptor Aptamers, Sabarinath Jayaseelan

Legacy Theses & Dissertations (2009 - 2024)

Using systematic evolution of ligands by exponential enrichment (SELEX), our lab previously selected a class of competitive RNA aptamers against the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. One aptamer in this class was found to have a minimal, functional sequence of 58 nucleotides. In vitro transcription generates two RNA transcripts with the same sequence, which we named M1 and M2, both of which are required to work together to inhibit the AMPA receptors. Although the M1 and M2 species have the same sequence, they cannot be interconverted through unfolding by denaturation/refolding by renaturation. To probe the secondary structures and the thermodynamic …

Evidence Of A Novel Rna Secondary Structure In The Coding Region Of Hiv-1 Pol Gene., Qi Wang, Ian Barr, Feng Guo, Christopher Lee

Natural Sciences and Mathematics | Faculty Scholarship

RNA secondary structures play several important roles in the human immunodeficiency virus (HIV) life cycle. To assess whether RNA secondary structure might affect the function of the HIV protease and reverse transcriptase genes, which are the main targets of anti-HIV drugs, we applied a series of different computational approaches to detect RNA secondary structures, including thermodynamic RNA folding predictions, synonymous variability analysis, and covariance analysis. Each method independently revealed strong evidence of a novel RNA secondary structure at the junction of the protease and reverse transcriptase genes, consisting of a 107-nucleotide region containing three stems, A, B, and C. First, …

The Effect Of 1,25-Dihydroxy Vitamin D3 On At1 Cell Receptor Expression In Human Iliac Artery Endothelial Cells (Hiaec), Jenny Thomas

Theses and Dissertations

The renin-angiotensin system (RAS) plays an important part in homeostasis through angiotensin IPs role as a vasoconstrictor. Defects in the renin angiotensin system can lead to hypertension, heart attack, and stroke (Weir, 1999). Studies have shown an inverse relationship between Vitamin D3 and blood pressure (Li et al., 2002). While studies have been performed on vitamin D's effect on renin expression, little is known about vitamin D's effect on the angiotensin II high-affinity type 1 (ATi) receptor. The hypothesis for this study was that human iliac artery endothelial cells (HIAEC) supplemented with 1,25-dihydroxy vitamin D3 will express less AT] receptor …

Transcriptional Regulation Of The Bmp2 Gene: Retinoic Acid Induction In F9 Embryonal Carcinoma Cells And Saccharomyces Cerevisiae, Loree C. Heller, Yong Li, Kevin L. Abrams, Melissa B. Rogers

Bioelectrics Publications

Bmp2, a highly conserved member of the transforming growth factor-beta gene family, is crucial for normal development. Retinoic acid, combined with cAMP analogs, sharply induces the Bmp2 mRNA during the differentiation of F9 embryonal carcinoma cells into parietal endoderm. Retinoic acid (RA) also induces the Bmp2 gene in chick limb buds. Since normal Bmp2 expression may require an endogenous retinoid signal and aberrant Bmp2 expression may cause some aspects of RA-induced teratogenesis, we studied the mechanism underlying the induction of Bmp2. Measurements of the Bmp2 mRNA half-life and nuclear run-on assays …

Rna Base-Amino Acid Interaction Strengths Derived From Structures And Sequences, Brooke Lustig, S Arora, R L. Jernigan

Faculty Publications, Chemistry

We investigate RNA base-amino acid interactions by counting their contacts in structures and their implicit contacts in various functional sequences where the structures can be assumed to be preserved. These frequencies are cast into equations to extract relative interaction energetics. Previously we used this approach in considering the major groove interactions of DNA, and here we apply it to the more diverse interactions observed in RNA. Structures considered are the three different tRNA synthetase complexes, the U1A spliceosomal protein with an RNA hairpin and the BIV TARTat complex. We use binding data for the base frequencies for the seryl, aspartyl …

The Drosophila Melanogaster Rad54 Homolog, Dmrad54, Is Involved In The Repair Of Radiation Damage And Recombination, Rolf Kooistra, José B. M. Zonneveld, Anja De Jong, Jan C. J. Eeken, Chris J. Osgood, Jean-Marie Buerstedde, Paul H. M. Lohman, Albert Pastink

Biological Sciences Faculty Publications

The RAD54 gene of Saccharomyces cerevisiae plays a crucial role in recombinational repair of double-strand breaks in DNA. Here the isolation and functional characterization of the RAD54 homolog of the fruit fly Drosophila melanogaster, DmRAD54, are described. The putative Dmrad54 protein displays 46 to 57% identity to its homologs from yeast and mammals. DmRAD54 RNA was detected at all stages of fly development, but an increased level was observed in early embryos and ovarian tissue. To determine the function of DmRAD54, a null mutant was isolated by random mutagenesis. DmRAD54-deficient flies develop normally, but the females …

Molecular Study Of The B19 (Human) Pathogenic Parvovirus, Jamshed Ayub

Theses and Dissertations in Biomedical Sciences

The B19 (human) parvovirus is a small single stranded DNA virus of 5.4 kilobases. B19 is specific for erythroid progenitor cells and has been propagated in vitro only with human erythroid bone marrow. Replication of viral DNA and the viral protein products of B19 appear similar to those of other animal parvoviruses. However, B19 differs from other parvoviruses in some important aspects, which include the initiation of all transcripts at a strong left side promoter (p6) and the absence of a functional internal promoter. B19 has an unusual transcription map which is described in this study.

The transcription map of …

The Purification Of Ribosomal Rna Gene Chromatin From Physarum Polycephalum, Sally A. Amero, Roy C. Ogle, John L. Keating, Vicky L. Montoya, Wendy L. Murdoch, Robert M. Grainger

School of Medical Diagnostics & Translational Sciences Publications

We have undertaken the purification of ribosomal RNA gene (rDNA) chromatin from the slime mold Physarum polycephalum, in order to study its chromatin structure. In this organism rDNA exists in nucleoli as highly repeated minichromosomes, and one can obtain crude chromatin fractions highly enriched in rDNA from isolated nucleoli. We first developed a nucleolar isolation method utilizing polyamines as stabilization agents that results in a chromatin fraction containing far more protein than is obtained by the more commonly used divalent cation isolation methods. The latter method appears to result in extensive histone loss during chromatin isolations. Two methods were then …

Investigation Of Complex Formation By Oligomers Of Cytosine And Guanosine, Steven Roberts Davis

Chemistry & Biochemistry Theses & Dissertations

Duplex formation between oligo(C:G) _n where n=3 to 4 was shown not to occur under conditions favorable for duplex formation between poly G and poly C. Instead, a stable guano sine self-structure was found to form which a T_m of 50°C for (Gp)₃ and 80°C for (Gp)₄ at strand concentrations of 10^-5M in 1M NaCl. Neither a duplex nor a self-structure formed in the absence of salt.

Oligomers of guanosine and cytosine were obtained by basic hydrolysis and separated according to chain length using DEAE Sephadex column chromatography. Separation of cytosine oligomers with chain lengths …

In Vitro Enzymatic Assay Of Rna Methylation, Pamela Jean Eubanks Gallup

Chemistry & Biochemistry Theses & Dissertations

An assay procedure for in vitro enzymatic methylation of mannnalian ribosomal RNA has been developed in this study. The assay procedure, utilized for the comparison of normal and neoplastic methylase activities (using mouse liver and Ehrlich ascites cells as sources of enzyme), is a modification of previously published methods (52,53). A 100,000 x g supernatant (SlOO) enzyme preparation was incubated with 28S-5.8S rRNA and tritium-labeled S-adenosyl-L-methionine. The RNA was extracted, applied to DEAE cellulose paper, washed, and the radioactivity counted. The neoplastic cell methylase preparation was more active in methylating both exogenous neoplastic and normal 28S-5.8S rRNA than the normal …

The Association Of 5.8 S With 28s Ribosomal Rna, Nandita Banerjee

Chemistry & Biochemistry Theses & Dissertations

5.8S rRNA is a low molecular weight ribosomal RNA which is noncovalently bonded to the larger ribosomal subunit 28S rRNA; through its 3' end and through its 5' end. This interaction is an integral part of the ribosome, and plays an important role in the ribosome structure and function.

There is a high degree of homology between the 5.8S rRNA primary structures of rat, turtle and chicken. The base sequence of rat 5.8S rRNA differs only in one position from that of turtle and in three positions fr.om that of cl1.icken. Tl1ere is a single purine substitution at the 5' …

A Study Of 5-Fluorouracil: Its Effects And Mode Of Action In Drosophila Melanogaster, John B. Jenkins Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations involving the fluorinated pyrimidine, 5-fluorouracil, and its effects on viruses, bacteria, plants and mammals, have brought to light the following facts: FU inhibits the growth of bacteria, plants and mammalian cells and it decreases the ability of certain viruses to produce progeny. In other words, FU is an antimetabolite that inhibits growth and/or reproduction. Two mechanisms have emerged from these studies to define the mode of action of FU. The first mechanism involves the incorporation of the compound into the RNA of the organism thus altering the base sequence and creating a non functional or damaging nucleic acid. The …