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The nucleotide sequences of five lysine tRNAs from murine lymphoma and Balb/3T3Hayenga, Kirk J. January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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RNA editing and autophagy in Drosophila melanogasterParo, Simona January 2012 (has links)
Post-transcriptional regulation of gene expression involves a diverse set of mechanisms such as RNA splicing, RNA localization, and RNA turn-over. Adenosine to Inosine (A-to-I) RNA editing is an additional post-transcriptional regulatory mechanism. Temporally, it occurs after transcription and before RNA splicing and has been shown in some instances to possibly modulate alternative splicing events. This is the case for example, with the pre-mRNA encoding the GluR- 2 subunit of AMPA receptor, a glutamate-activated ion channel. ADAR (Adenosine deaminase acting on RNA) proteins bind to double-stranded regions in pre-messenger RNAs. They deaminate specific adenosines, generating inosines; if the editing event occurs within the coding region, inosine is then interpreted as guanosine by the ribosomal translational machinery, changing codon meaning. These editing events can increase the repertoire of translated proteins, generating molecular diversity and modifying protein function. In mammals there are four ADAR genes: ADAR1, ADAR2, ADAR3 and TENR. ADAR3 and TENR are enzymatically inactive. All the proteins have two types of functional domains: (i) the catalytic deaminase domain at the carboxyl-terminus and (ii) the double stranded RNA binding domains, dsRBDs, at the amino terminus. ADAR1 and ADAR2 differ significantly at the amino terminus, by the number of the dsRNA binding domains (three and two dsRBDs for ADAR1 and ADAR2 protein, respectively). The differences observed between ADAR1 and ADAR2 are likely to reflect the different repertoires of substrates edited by these two enzymes. Data concerning the conservation of Adar genes throughout evolution suggest that Drosophila melanogaster has a unique Adar gene which is a true ortholog of human ADAR2 rather than an invertebrate gene ancestral for both vertebrate genes. Flies that are null mutants for Adar (Adar5G1 mutants) display profound behavioral and locomotive deficits. Impairment in motor activity of the mutants is succeeded by age-dependent neurodegeneration, characterized by swelling within the Adar-null mutant fly brain. The initial focus of my thesis was to elucidate what causes Adar mutant phenotypes or, whether it is possible, to suppress them. I took advantage of Drosophila genetics to establish a forward genetic screen for suppressors of reduced Adar5G1 viability which is approximately 20-30% in comparison to control flies at eclosion. The results from an interaction screen on Chromosome 2L were further confirmed using Exelixis P-element insertion lines. The screen revealed that decreasing Tor (Target of rapamycin) expression suppresses Adar mutant phenotypes. TOR plays a role in maintaining cellular homeostasis by balancing the metabolic processes. It controls anabolic events by phosphorylating eukaryotic translation initiation factor 4E-binding protein (4E-BP) and p70 S6 kinase (S6K) and inducing cap-mediated translation. However, different types of stress, signals or increased demand in catabolic processes, converge to reduce TOR enzymatic activity. This results in long-lived proteins and organelles being engulfed in double-membrane vesicles and degraded; this bulk degradation process is called (macro)autophagy. The second aim of my thesis was to clarify which pathway, downstream to TOR, was responsible for the suppression of Adar-null phenotypes. I mimicked the effect of reduced Tor expression by manipulating genetically the cap-dependent translation and the autophagy pathways. Interestingly, boosting the expression of Atg (autophagy specific genes) genes, such as, Atg1 and Atg5, thereby increasing the activation rate of the autophagy pathway, suppresses Adar5G1 phenotypes. Finally, I found that Adar5G1 mutant flies have an increased level of autophagy that is observable from the larval stage. I investigated possible stresses affecting our mutants; Adar-mutant larval fat cells show ER stress triggering an unfolded protein response as indicated by expression of XbpI-eGFP reporter. Thus, ER stress might induce increased autophagy and it can lead to locomotive impairments and neurodegeneration in Adar-null mutants. These results suggest a function for the Adar gene in regulating cellular stress.
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Interactions of picornavirus internal ribosome entry sites with cellular proteinsStassinopoulos, Ioannis A. January 2000 (has links)
No description available.
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Identification and characterization of E3 ubiquitin ligase SIAH1 as a regulatory target of microRNA-135a in HeLa cells梁靄褳, Leung, Oi-ning. January 2008 (has links)
published_or_final_version / Medical Sciences / Master / Master of Medical Sciences
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A study of microRNA-132 and -212 in murine granulosa cells during folliculogenesisLin, Sau-wah, Selma., 林秀華. January 2010 (has links)
published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy
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The role of FIS in tyrT transcriptional regulationLazarus, Linda Ruth January 1992 (has links)
No description available.
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Expression and immunogenicity of Theiler's virus proteinsJohnston, Ian Charles David January 1994 (has links)
No description available.
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The accumulation of proteins in the Xenopus oocyte nucleusDingwall, C. January 1985 (has links)
The ability of proteins to accumulate in the nucleus has been studied by injecting nucleoplasmin and calf thymus histone H1 into the cytoplasm of Xenopus oocytes. Nucleoplasmin, the most abundant protein in the Xenopus oocyte nucleus is pentameric and proteolysis of the nuceloplasmin pentamer produces a relatively protease resistant 'core' molecule that cannot enter the nucleus after microinjection into the cytoplasm. The polypeptide domain ('lq tail') of each subunit removed by proteolysis was obtained as a discrete fragment and has the ability to accumulate in the nucleus. Partially cleaved pentameric molecules with a single intact sub unit can still accumulate in the nucleus. Therefore a polypeptide domain of nucleoplasmin has been found that is both necessary and sufficient for accumulation in the nucleus. When the `core' molecule was injected directly into the oocyte nucleus it remained there, indicating that the 'tail' region confers selective entry rather than selective retention. In the case of histone H1 a proteolytic fragment encompassing the carboxyterminal domain can accumulate in the nucleus. The amino acids lysine, proline and alanine comprise 75 of the 89 amino acids in this fragment. Since the remaining 14 amino acids are scattered throughout the fragment and not clustered any primary sequence specifying entry into the nucleus would seem necessarily to involve the amino acids lysine, proline and alanine. Positive charge alone cannot explain the accumulation of this gragment since poly L-lysine does not accumulate after microinjection into the cytoplasm. Fragments encompassing other domains of the molecule are so unstable in the oocyte that their ability to accumulate in the oocyte nucleus cannot be assayed. The gene for nucleoplasmin has been cloned and sequences have been found in the 'tail' region of nuceloplasmin that show homology to sequences identified in other nuclear proteins that appear to constitute a signal specifying nuclear localisation.
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Cellular proteins in picornavirus replicationBailey, Daniel John January 1999 (has links)
No description available.
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A study of the Xenopus and mouse U7 snRNAsWatkins, Nicholas James January 1994 (has links)
No description available.
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