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Identification And Stoichiometric Analysis Of The Monosomal Translational Complex, Xin Wang

Doctoral Dissertations

The identification of the components involved in translational complexes has relied primarily on in vitro studies. Determining which proteins associate together in these complexes, under what conditions they do so, and how the composition of the complexes change under different conditions have became the key issues of in vivo studies. After a one-step affinity purification, using a novel technique of analytical ultracentrifugation with a fluorescence detection system (AU-FDS) I have identified a 77S monosomal translational complex in the yeast Saccharomyces cerevisiae. Major components of the 77S complex include the 80S ribosome, mRNA, and components of the closed-loop structure, eIF4E, eIF4G1/eIF4G2 …

The Identification And Characterization Of The Interaction Between Upf1 And Pab1 During Nonsense-Mediated Decay & The Identification Of Novel Protein Complexes Associated With Translation Termination Factor Erf1, Roy Richardson

Doctoral Dissertations

There are still many protein interactions that occur during translation termination that are poorly understood. One of the important termination pathways still under investigation is nonsense-mediated decay (NMD), which rapidly degrades mRNAs that contain a premature stop codon (PTC). I identified that the interaction between Upfl, which is required for NMD, and PAB1 occurs via the RRM1 domain of PAB1 in the yeast Saccharomyces cerevisiae. Determining the role of this interaction during NMD was performed with pulse-chase assays using a PGKlpG mRNA. These assays revealed that the interaction between Upfl and PAB1 is required for a shift from distributive to …

Regulation Of The Catalytic And Allosteric Properties Of Photoreceptor Phosphodiesterase (Pde6) By The Glutamic Acid-Rich Protein-2 (Garp2), Wei Yao

Doctoral Dissertations

The photoreceptor phosphodiesterase (PDE6) must be precisely regulated to control the sensitivity, amplitude, and kinetics of the photoresponse during excitation, termination and adaptation to light stimulation in rod and cone photoreceptors. The central hypothesis of this thesis is that one PDE6 binding partner, the glutamic acid-rich protein (GARP2), may regulate PDE6 to reduce its "dark noise", enhance its sensitivity and conserve metabolic energy during rod photoresponse saturation.

The first aim of this research is to better understand the unique biochemical and biophysical characteristics of GARP2 in order to reveal its functional attributes for regulating PDE6 during phototransduction in rod photoreceptors. …

Patterns Of Cytosine Methylation In The Genome Of Caenorhabditis Elegans, Kazufusa Okamoto

Doctoral Dissertations

Recent large-scale comparative analysis of cytosine DNA methylation across diverse eukaryotes suggest that early features of DNA methylation present in the last common ancestor of all eukaryotes some 1.6 to 1.8 billion years ago included the methylation of gene bodies and transposable elements (Zemach, McDaniel et al. 2010; Parfrey, Lahr et al. 2011). These potentially ancient patterns may reflect a primitive role of methylation in transcriptional fidelity and as a mechanism to protect the germ line from transposon, or repeat, mediated mutation. Because spurious transcription and mutation are hypothesized to be among the critical limiting factors to genome size, an …