Transcriptional Regulation of Yeast CUP1 gene
Item
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Title
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Transcriptional Regulation of Yeast CUP1 gene
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Identifier
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d_2009_2013:22278bb029d5:11417
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identifier
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11728
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Creator
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Wimalarathna, Roshini Nilupama,
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Contributor
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Chang-Hui Shen
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology | Molecular biology
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Abstract
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The yeast CUP1 gene encodes a metallothionein required for cell growth at high copper concentrations. The induction of CUP1 with copper results in activator-dependent nucleosome repositioning. To further understand the mechanism of CUP1 activation, it is necessary to identify which chromatin remodeler(s) is/are involved in CUP1 induction. Here, we demonstrated that both ino80Delta and snf2Delta cells grew well in the absence of copper, but were inviable in the presence of copper, indicating that they are required for CUP1 expression. Furthermore, CUP1 mRNA did not significantly increase in mutants lacking either remodeler in the presence of copper, suggesting that they regulate CUP1 induction at the transcriptional level. Both isw1Delta and rsc3Delta cells displayed similar growth patterns as WT cells in the presence of copper. Further CUP1 mRNA was significantly increasing in both isw1Delta and rsc3Delta cells showing similar pattern as WT cells. This observation suggests that ISW1 and RSC3 remodeling complexes have no positive effect in CUP1 expression. We also demonstrated, using chromatin immunoprecipitation, that both INO80 and SWI/SNF are present at the promoter in the wild type cells and they were dependent on each other to be recruited to the CUP1 promoter. Both chromatin remodeling activity and targeted histone acetylation were not observed in ino80Delta or snf2Delta strains at the CUP1 promoter. These results suggest that both INO80 and SWI/SNF directly participate in CUP1 chromatin remodeling, and that histone acetylation is recruited after the arrival of chromatin remodelers. We also observed that more polII was recruited to the CUP1 promoter under inducing conditions and that such a recruitment was not observed in ino80Delta or snf2Delta strains. Furthermore, we observed that both Snf2p and Ino80p were activator-dependent. Our observations provide direct evidence for the involvement of both INO80 and SWI/SNF remodelers in CUP1 activation. In light of these findings, we propose a working model for CUP1 activation.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Biology
