The β-1,3-glucanosyltransferase Gas1 regulates Sir2-mediated rDNA stability in<i>Saccharomyces cerevisiae</i>

Ha, Cheol Woong; Kim, Kwantae; Chang, Yeon Ji; Kim, Bongkeun; Huh, Won-Ki

doi:10.1093/nar/gku570

Cited by 20 publications

(22 citation statements)

References 64 publications

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“…Furthermore, the increased rate of this USCE at rDNA regions generates extrachromosomal rDNA circles (ERCs), which are responsible for premature cell senescence in budding yeast (20). Nevertheless, under normal conditions, rDNA repeats continue to be rather stable because rDNA recombination is negatively regulated through rDNA silencing (21).…”

Section: Pathways For Rdna Silencingmentioning

confidence: 99%

The Epigenetic Pathways to Ribosomal DNA Silencing

Srivastava

Ahn

2016

Microbiol Mol Biol Rev

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SUMMARYHeterochromatin is the transcriptionally repressed portion of eukaryotic chromatin that maintains a condensed appearance throughout the cell cycle. At sites of ribosomal DNA (rDNA) heterochromatin, epigenetic states contribute to gene silencing and genome stability, which are required for proper chromosome segregation and a normal life span. Here, we focus on recent advances in the epigenetic regulation of rDNA silencing inSaccharomyces cerevisiaeand in mammals, including regulation by several histone modifications and several protein components associated with the inner nuclear membrane within the nucleolus. Finally, we discuss the perturbations of rDNA epigenetic pathways in regulating cellular aging and in causing various types of diseases.

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Section: Pathways For Rdna Silencingmentioning

confidence: 99%

The Epigenetic Pathways to Ribosomal DNA Silencing

Srivastava

Ahn

2016

Microbiol Mol Biol Rev

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“…In budding yeast, cells lacking Gas1 have weakened and abnormal cell walls and are sensitive to cell wall-perturbing drugs. Recently, however, a surprising new role for Gas1 activity has been identified in the regulation of transcriptional silencing at rDNA loci ( Eustice and Pillus, 2014 ; Ha et al , 2014 ; Koch and Pillus, 2009 ). In particular, it has been suggested that Gas1 physically interacts with Sir2, an nicotinamide adenine dinucleotide (NAD) + -dependent histone deacetylase that is a subunit of the rDNA silencing complex (RENT: regulator of nucleolar silencing and telophase exit), to repress Pol II-dependent transcription at the rDNA locus ( Huang and Moazed, 2003 ).…”

Section: Resultsmentioning

confidence: 99%

Inferring orthologous gene regulatory networks using interspecies data fusion

2015

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Motivation: The ability to jointly learn gene regulatory networks (GRNs) in, or leverage GRNs between related species would allow the vast amount of legacy data obtained in model organisms to inform the GRNs of more complex, or economically or medically relevant counterparts. Examples include transferring information from Arabidopsis thaliana into related crop species for food security purposes, or from mice into humans for medical applications. Here we develop two related Bayesian approaches to network inference that allow GRNs to be jointly inferred in, or leveraged between, several related species: in one framework, network information is directly propagated between species; in the second hierarchical approach, network information is propagated via an unobserved ‘hypernetwork’. In both frameworks, information about network similarity is captured via graph kernels, with the networks additionally informed by species-specific time series gene expression data, when available, using Gaussian processes to model the dynamics of gene expression.Results: Results on in silico benchmarks demonstrate that joint inference, and leveraging of known networks between species, offers better accuracy than standalone inference. The direct propagation of network information via the non-hierarchical framework is more appropriate when there are relatively few species, while the hierarchical approach is better suited when there are many species. Both methods are robust to small amounts of mislabelling of orthologues. Finally, the use of Saccharomyces cerevisiae data and networks to inform inference of networks in the budding yeast Schizosaccharomyces pombe predicts a novel role in cell cycle regulation for Gas1 (SPAC19B12.02c), a 1,3-beta-glucanosyltransferase.Availability and implementation: MATLAB code is available from http://go.warwick.ac.uk/systemsbiology/software/.Contact: d.l.wild@warwick.ac.ukSupplementary information: Supplementary data are available at Bioinformatics online.

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“…In addition, increased deposition of chitin was seen at hyphal tips, and alterations in cell wall carbohydrate epitopes were seen that can help account for the alkaline sensitivity of the gas3 mutant. However, it should also be noted that aside from the role in glucan remodeling, at least one of Gas proteins, namely, S. cerevisiae GAS1, has been shown to affect transcriptional silencing via carbohydrate modification of chromatin and/or via maintenance of ribosomal DNA (rDNA) integrity (12,48). Thus, it cannot be ruled out that the effects of Bbgas3 may also involve such mechanisms.…”

Section: Discussionmentioning

confidence: 99%

The Beauveria bassiana Gas3 β-Glucanosyltransferase Contributes to Fungal Adaptation to Extreme Alkaline Conditions

Luo

Zhang

Liu

et al. 2018

Appl Environ Microbiol

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Fungal β-1,3-glucanosyltransferases are cell wall-remodeling enzymes implicated in stress response, cell wall integrity, and virulence, with most fungal genomes containing multiple members. The insect-pathogenic fungus displays robust growth over a wide pH range (pH 4 to 10). A random insertion mutant library screening for increased sensitivity to alkaline (pH 10) growth conditions resulted in the identification and mapping of a mutant to a β-1,3-glucanosyltransferase gene (). expression was pH dependent and regulated by the PacC transcription factor, which activates genes in response to neutral/alkaline growth conditions. Targeted gene knockout of resulted in reduced growth under alkaline conditions, with only minor effects of increased sensitivity to cell wall stress (Congo red and calcofluor white) and no significant effects on fungal sensitivity to oxidative or osmotic stress. The cell walls of Δ aerial conidia were thinner than those of the wild-type and complemented strains in response to alkaline conditions, and β-1,3-glucan antibody and lectin staining revealed alterations in cell surface carbohydrate epitopes. The Δ mutant displayed alterations in cell wall chitin and carbohydrate content in response to alkaline pH. Insect bioassays revealed impaired virulence for the Δ mutant depending upon the pH of the media on which the conidia were grown and harvested. Unexpectedly, a decreased median lethal time to kill (LT, i.e., increased virulence) was seen for the mutant using intrahemocoel injection assays using conidia grown at acidic pH (5.6). These data show that BbGas3 acts as a pH-responsive cell wall-remodeling enzyme involved in resistance to extreme pH (>9). Little is known about adaptations required for growth at high (>9) pH. Here, we show that a specific fungal membrane-remodeling β-1,3-glucanosyltransferase gene () regulated by the pH-responsive PacC transcription factor forms a critical aspect of the ability of the insect-pathogenic fungus to grow at extreme pH. The loss of resulted in a unique decreased ability to grow at high pH, with little to no effects seen with respect to other stress conditions, i.e., cell wall integrity and osmotic and oxidative stress. However, pH-dependent alternations in cell wall properties and virulence were noted for the Δas3 mutant. These data provide a mechanistic insight into the importance of the specific cell wall structure required to stabilize the cell at high pH and link it to the PacC/Pal/Rim pH-sensing and regulatory system.

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The β-1,3-glucanosyltransferase Gas1 regulates Sir2-mediated rDNA stability inSaccharomyces cerevisiae

Cited by 20 publications

References 64 publications

The Epigenetic Pathways to Ribosomal DNA Silencing

The Epigenetic Pathways to Ribosomal DNA Silencing

Inferring orthologous gene regulatory networks using interspecies data fusion

The Beauveria bassiana Gas3 β-Glucanosyltransferase Contributes to Fungal Adaptation to Extreme Alkaline Conditions

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