The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing
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Case Western Reserve University School of Graduate Studies / OhioLINK
2010
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=case1283302534 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-case12833025342021-08-03T05:33:51Z The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing Bifano, Abby Lynn Shumaker Biochemistry Molecular Biology DEAD-box proteins group I intron splicing catalytic RNAs mitochondrial RNA processing <i>Saccharomyces</i> <i>cerevisiae</i> <p>DEAD-box proteins are a large class of ATPases that are involved in almost all aspects of RNA metabolism. Many of these enzymes have been shown to possess common biochemical properties <i>in</i> <i>vitro</i>, including the ability to bind and hydrolyze ATP, to bind nucleic acids, and to unwind and anneal nucleic acids strands and, therefore, DEAD-box proteins are generally thought to modulate RNA structure <i>in</i> <i>vivo</i>. To a large degree, however, the functions of individual DEAD-box proteins <i>in</i> <i>vivo</i> remain unclear and, furthermore, it is unknown which of the aforementioned properties are important for their activities <i>in</i> <i>vivo</i>. Thus, it is critical to define the mechanisms by which DEAD-box proteins function with their native substrates, in order to understand the permissible roles of these important enzymes in RNA metabolism and, more broadly, gene expression.</p><p>The work presented here is an investigation into the role of a representative DEAD-box protein, Mss116p, and the mechanisms by which it functions in the splicing of a native group I intron substrate, the aI5β intron from the mitochondrial <i>COX1</i> gene in <i>S</i>. <i>cerevisiae</i>. In the first study, we show that Mss116p, in an ATP-dependent manner, specifically facilitates the second step of aI5β splicing <i>in</i> <i>vitro</i> and that its role in exon ligation is temporally controlled and dependent on the “upstream” activity of another RNA binding protein, Mrs1p. We also demonstrate that the ability of Mss116p to efficiently hydrolyze ATP, rather than unwind a stable model duplex, is critical for its function in aI5β splicing.</p><p>In the second study, we explored the catalytic properties of Mss116p that were required for the splicing of the aI5β intron, as well as additional native intron substrates, <i>in</i> <i>vivo</i>. Similar to our biochemical results, we found that efficient ATPase activity, rather than robust unwinding activity, was required for Mss116p’s role in the splicing of all examined intron substrate <i>in</i> <i>vivo</i>. Given that ATP hydrolysis stimulates the recycling of DEAD-box proteins, our observations support a model in which enzyme turnover is a crucial factor in the splicing function of Mss116p.</p> 2010 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1283302534 http://rave.ohiolink.edu/etdc/view?acc_num=case1283302534 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
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NDLTD |
| topic |
Biochemistry Molecular Biology DEAD-box proteins group I intron splicing catalytic RNAs mitochondrial RNA processing <i>Saccharomyces</i> <i>cerevisiae</i> |
| spellingShingle |
Biochemistry Molecular Biology DEAD-box proteins group I intron splicing catalytic RNAs mitochondrial RNA processing <i>Saccharomyces</i> <i>cerevisiae</i> Bifano, Abby Lynn Shumaker The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| author |
Bifano, Abby Lynn Shumaker |
| author_facet |
Bifano, Abby Lynn Shumaker |
| author_sort |
Bifano, Abby Lynn Shumaker |
| title |
The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| title_short |
The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| title_full |
The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| title_fullStr |
The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| title_full_unstemmed |
The Role of a Nuclear-Encoded DEAD-box Protein from <i>Saccharomyces</i> <i>cerevisiae</i> in Mitochondrial Group I Intron Splicing |
| title_sort |
role of a nuclear-encoded dead-box protein from <i>saccharomyces</i> <i>cerevisiae</i> in mitochondrial group i intron splicing |
| publisher |
Case Western Reserve University School of Graduate Studies / OhioLINK |
| publishDate |
2010 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=case1283302534 |
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