Abstract
In Saccharomyces cerevisiae, the stability of highly repetitive rDNA array is maintained through transcriptional silencing. Recently, a β-1,3-glucanosyltransferase Gas1 has been shown to play a significant role in the regulation of transcriptional silencing in S. cerevisiae. Here, we show that the gas1Δ mutation increases rDNA silencing in a Sir2-dependent manner. Remarkably, the gas1Δ mutation induces nuclear localization of Msn2/4 and stimulates the expression of PNC1, a gene encoding a nicotinamidase that functions as a Sir2 activator. The lack of enzymatic activity of Gas1 or treatment with a cell wall-damaging agent, Congo red, exhibits effects similar to those of the gas1Δ mutation. Furthermore, the loss of Gas1 or Congo red treatment lowers the cAMP-dependent protein kinase (PKA) activity in a cell wall integrity MAP kinase Slt2-dependent manner. Collectively, our results suggest that the dysfunction of Gas1 plays a positive role in the maintenance of rDNA integrity by decreasing PKA activity and inducing the accumulation of Msn2/4 in the nucleus. It seems that nuclear-localized Msn2/4 stimulate the expression of Pnc1, thereby enhancing the association of Sir2 with rDNA and promoting rDNA stability.
© The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Congo Red
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DNA, Ribosomal*
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DNA-Binding Proteins / metabolism
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Gene Deletion
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Gene Expression Regulation, Fungal*
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Gene Silencing*
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Glucan Endo-1,3-beta-D-Glucosidase / genetics
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Glucan Endo-1,3-beta-D-Glucosidase / metabolism
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Glucan Endo-1,3-beta-D-Glucosidase / physiology*
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism
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Membrane Glycoproteins / physiology*
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Mitogen-Activated Protein Kinases / metabolism
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Nicotinamidase / biosynthesis
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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / biosynthesis
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Saccharomyces cerevisiae Proteins / physiology*
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Silent Information Regulator Proteins, Saccharomyces cerevisiae / metabolism*
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Sirtuin 2 / metabolism*
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Transcription Factors / metabolism
Substances
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DNA, Ribosomal
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DNA-Binding Proteins
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GAS1 protein, S cerevisiae
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MSN2 protein, S cerevisiae
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MSN4 protein, S cerevisiae
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Membrane Glycoproteins
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Saccharomyces cerevisiae Proteins
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Silent Information Regulator Proteins, Saccharomyces cerevisiae
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Transcription Factors
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Congo Red
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Mitogen-Activated Protein Kinases
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SLT2 protein, S cerevisiae
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1,3-beta-glucanosyltransferase
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Glucan Endo-1,3-beta-D-Glucosidase
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SIR2 protein, S cerevisiae
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Sirtuin 2
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Nicotinamidase
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PNC1 protein, S cerevisiae