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ETDs in this community are being checked for completeness and are in the process of being transferred to their respective collections under the FGS ETD collection umbrella.
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Browsing SWORD Deposit by Author "Audette, Gerald F."
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Item Open Access Analysis of the uncharacterized La-related protein, Slr1p from Schizosaccharomyces pombeSiniavskaia, Lidia; Bayfield, Mark; Sheng, Yi; Cheung, Peter; Audette, Gerald F.La is a ubiquitous RNA-binding phosphoprotein found in nearly all eukaryotes. La binds to nascent polymerase III transcripts via their UUU-3'OH motif and protects these RNAs from 3'exonucleolytic digestion. La also exhibits RNA chaperone activity, is involved in intracellular trafficking, and stimulates the translation of certain subsets of mRNA via unknown mechanisms. Structurally, all La proteins harbour an N-terminal La module consisting of a La motif (LAM) and an RNA recognition motif. The LAM displays a high degree of conservation, not only among genuine La proteins but also in La-related proteins (LARPs) of which 4 families have been identified: LARP 1, 4, 6 and 7. Although they fulfill important cellular functions, LARPs are generally poorly understood. In an effort to characterize LARPs in greater detail, a simple LARP from Schizosaccharomyces pombe, Slrlp, was chosen as an ideal candidate to study. From an evolutionary perspective, we propose that Slr1p constitutes an ancestor to LARPs in higher eukaryotes, and therefore, characterization of its function may provide insight into the divergent roles of its extended relatives. We performed RNA chaperone assays, electromobility shift assays, localization studies via indirect immunofluorescence, as well as co-immunoprecipitation and mass spectrometry to determine Slr1p associated factors. Taken together, our results suggest that Slr1p is an RNA chaperone, it associates with fatty acid synthase as well as translation initiation factors in the cytoplasm, and that it binds to RNAs in a UUU-3'OH independent manner.Item Open Access The Staphylococcus aureus Ser/Thr kinase Stk1 specifically phosphorylates GraR, a transcription factor involved in global signal transductionFridman, Michael; Hudak, Katalin; Audette, Gerald F.; McDermott, JohnStaphylococcus aureus coordinates gene expression at appropriate times throughout its life cycle. The work herein demonstrates S. aureus serine-threonine kinase (Stk1) can phosphorylate the response regulator GraR in vitro. Phosphorylation was confirmed by mass spectrometry and specifically occurs at the DNA-binding domain at three threonine positions: Thr128, 130 and 149. Stk1 could not phosphorylate BceR, a GraR homolog with 56% sequence similarity. We have also discovered, through in vivo work, novel phenotypes of an S. aureus [delta]graR knockout. It is shown that GraR plays a role in proper cell growth, division and wall teichoic acid maintenance. [delta]graR mutant complemented with ectopically expressed GraR-WT reverts phenotypes to normal, whereas GraR-D51N does not. Collectively our data suggest a novel, more global, regulatory role for the GraSR system. Understanding signaling and post-translational modification networks and their downstream effects is essential in order to rationally develop new strategies to treat S. aureus infections.