1
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Kamata K, Ayano T, Oki M. Spt3 and Spt8 Are Involved in the Formation of a Silencing Boundary by Interacting with TATA-Binding Protein. Biomolecules 2023; 13:biom13040619. [PMID: 37189367 DOI: 10.3390/biom13040619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
In Saccharomyces cerevisiae, a heterochromatin-like chromatin structure called the silencing region is present at the telomere as a complex of Sir2, Sir3, and Sir4. Although spreading of the silencing region is blocked by histone acetylase-mediated boundary formation, the details of the factors and mechanisms involved in the spread and formation of the boundary at each telomere are unknown. Here, we show that Spt3 and Spt8 block the spread of the silencing regions. Spt3 and Spt8 are members of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, which has histone acetyltransferase activity. We performed microarray analysis of the transcriptome of spt3Δ and spt8Δ strains and RT-qPCR analysis of the transcript levels of genes from the subtelomeric region in mutants in which the interaction of Spt3 with TATA-binding protein (TBP) is altered. The results not only indicated that both Spt3 and Spt8 are involved in TBP-mediated boundary formation on the right arm of chromosome III, but also that boundary formation in this region is DNA sequence independent. Although both Spt3 and Spt8 interact with TBP, Spt3 had a greater effect on genome-wide transcription. Mutant analysis showed that the interaction between Spt3 and TBP plays an important role in the boundary formation.
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2
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D’Angiolo M, Yue JX, De Chiara M, Barré BP, Giraud Panis MJ, Gilson E, Liti G. Telomeres are shorter in wild Saccharomyces cerevisiae isolates than in domesticated ones. Genetics 2023; 223:iyac186. [PMID: 36563016 PMCID: PMC9991508 DOI: 10.1093/genetics/iyac186] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/02/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022] Open
Abstract
Telomeres are ribonucleoproteins that cap chromosome-ends and their DNA length is controlled by counteracting elongation and shortening processes. The budding yeast Saccharomyces cerevisiae has been a leading model to study telomere DNA length control and dynamics. Its telomeric DNA is maintained at a length that slightly varies between laboratory strains, but little is known about its variation at the species level. The recent publication of the genomes of over 1,000 S. cerevisiae strains enabled us to explore telomere DNA length variation at an unprecedented scale. Here, we developed a bioinformatic pipeline (YeaISTY) to estimate telomere DNA length from whole-genome sequences and applied it to the sequenced S. cerevisiae collection. Our results revealed broad natural telomere DNA length variation among the isolates. Notably, telomere DNA length is shorter in those derived from wild rather than domesticated environments. Moreover, telomere DNA length variation is associated with mitochondrial metabolism, and this association is driven by wild strains. Overall, these findings reveal broad variation in budding yeast's telomere DNA length regulation, which might be shaped by its different ecological life-styles.
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Affiliation(s)
- Melania D’Angiolo
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
| | - Jia-Xing Yue
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Sun Yat-sen University Cancer Center (SYSUCC), 651 Dongfeng Road East, China
| | - Matteo De Chiara
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
| | - Benjamin P Barré
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
| | - Marie-Josèphe Giraud Panis
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
| | - Eric Gilson
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
- Department of Genetics, CHU, 06107 Nice, France
| | - Gianni Liti
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, 28 Avenue de Valombrose, 06107 Nice, France
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3
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Li M, Zhang Y, Deng J, Wang H, Ma J, Wang W, Lyu L. Deletion of YJL218W reduces salt tolerance of Saccharomyces cerevisiae. J Basic Microbiol 2022; 62:930-936. [PMID: 35689329 DOI: 10.1002/jobm.202200029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/22/2022] [Accepted: 05/27/2022] [Indexed: 11/10/2022]
Abstract
The YJL218W open reading frame may be involved in peroxisomal biogenesis. However, whether it mediates salt tolerance is unclear. We found that after knockdown of YJL218W in Saccharomyces cerevisiae (S. cerevisiae), its salt tolerance was reduced and cell death was increased. Transcriptome sequencing and analysis further revealed that YJL218W knockdown mediated significant changes in the expression of 1432 messenger RNA (mRNAs), of which 603 were upregulated. KEGG enrichment analysis and polymerase chain reaction (PCR) assay indicated that YJL218W mediated the regulation of peroxisome-related genes. Therefore, YJL218W may regulate salt stress in S. cerevisiae by regulating peroxisome assembly.
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Affiliation(s)
- Mengyan Li
- School of Basic Medical Sciences, Kunming Medical University, Kunming, China.,Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, Yunnan, China
| | - Yu Zhang
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, Yunnan, China
| | - Juqing Deng
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, Yunnan, China
| | - Hanying Wang
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, Yunnan, China
| | - Jiaqing Ma
- School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Weiqun Wang
- School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Lechun Lyu
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, Yunnan, China
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4
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Österberg L, Domenzain I, Münch J, Nielsen J, Hohmann S, Cvijovic M. A novel yeast hybrid modeling framework integrating Boolean and enzyme-constrained networks enables exploration of the interplay between signaling and metabolism. PLoS Comput Biol 2021; 17:e1008891. [PMID: 33836000 PMCID: PMC8059808 DOI: 10.1371/journal.pcbi.1008891] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/21/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
The interplay between nutrient-induced signaling and metabolism plays an important role in maintaining homeostasis and its malfunction has been implicated in many different human diseases such as obesity, type 2 diabetes, cancer, and neurological disorders. Therefore, unraveling the role of nutrients as signaling molecules and metabolites together with their interconnectivity may provide a deeper understanding of how these conditions occur. Both signaling and metabolism have been extensively studied using various systems biology approaches. However, they are mainly studied individually and in addition, current models lack both the complexity of the dynamics and the effects of the crosstalk in the signaling system. To gain a better understanding of the interconnectivity between nutrient signaling and metabolism in yeast cells, we developed a hybrid model, combining a Boolean module, describing the main pathways of glucose and nitrogen signaling, and an enzyme-constrained model accounting for the central carbon metabolism of Saccharomyces cerevisiae, using a regulatory network as a link. The resulting hybrid model was able to capture a diverse utalization of isoenzymes and to our knowledge outperforms constraint-based models in the prediction of individual enzymes for both respiratory and mixed metabolism. The model showed that during fermentation, enzyme utilization has a major contribution in governing protein allocation, while in low glucose conditions robustness and control are prioritized. In addition, the model was capable of reproducing the regulatory effects that are associated with the Crabtree effect and glucose repression, as well as regulatory effects associated with lifespan increase during caloric restriction. Overall, we show that our hybrid model provides a comprehensive framework for the study of the non-trivial effects of the interplay between signaling and metabolism, suggesting connections between the Snf1 signaling pathways and processes that have been related to chronological lifespan of yeast cells.
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Affiliation(s)
- Linnea Österberg
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Iván Domenzain
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Julia Münch
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
- BioInnovation Institute, Copenhagen, Denmark
| | - Stefan Hohmann
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Marija Cvijovic
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
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5
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RNA Sequencing Reveals Specific TranscriptomicSignatures Distinguishing Effects of the [ SWI⁺] Prion and SWI1 Deletion in Yeast Saccharomyces cerevisiae. Genes (Basel) 2019; 10:genes10030212. [PMID: 30871095 PMCID: PMC6471900 DOI: 10.3390/genes10030212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/01/2019] [Accepted: 03/08/2019] [Indexed: 01/02/2023] Open
Abstract
Prions are infectious, self-perpetuating protein conformers. In mammals, pathological aggregation of the prion protein causes incurable neurodegenerative disorders, while in yeast Saccharomyces cerevisiae, prion formation may be neutral or even beneficial. According to the prevailing contemporary point of view, prion formation is considered to be a functional inactivation of the corresponding protein whose conformational state shifts from the functional monomeric one to the infectious aggregated one. The Swi1 protein forms the [SWI+] prion and belongs to the nucleosome remodeler complex SWI/SNF controlling the expression of a significant part of the yeast genome. In this work, we performed RNA sequencing of isogenic S. cerevisiae strains grown on the media containing galactose as the sole carbon source. These strains bore the [SWI+] prion or had its structural gene SWI1 deleted. The comparative analysis showed that [SWI+] affects genome expression significantly weaker as compared to the SWI1 deletion. Moreover, in contrast to [SWI+], the SWI1 deletion causes the general inhibition of translation-related genes expression and chromosome I disomy. At the same time, the [SWI+] prion exhibits a specific pattern of modulation of the metabolic pathways and some biological processes and functions, as well as the expression of several genes. Thus, the [SWI+] prion only partially corresponds to the loss-of-function of SWI1 and demonstrates several gain-of-function traits.
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6
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Schabort DTWP, Kilian SG, du Preez JC. Gene regulation in Kluyveromyces marxianus in the context of chromosomes. PLoS One 2018; 13:e0190913. [PMID: 29346402 PMCID: PMC5773181 DOI: 10.1371/journal.pone.0190913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/22/2017] [Indexed: 12/20/2022] Open
Abstract
Eukaryotes, including the unicellular eukaryotes such as yeasts, employ multiple levels of gene regulation. Regulation of chromatin structure through chromatin compaction cascades, and influenced by transcriptional insulators, might play a role in the coordinated regulation of genes situated at adjacent loci and expressed as a co-regulated cluster. Subtelomeric gene silencing, which has previously been described in the yeast Saccharomyces cerevisiae, is an example of this phenomenon. Transcription from a common regulatory element located around a shared intergenic region is another factor that could coordinate the transcription of genes at adjacent loci. Additionally, the presence of DNA binding sites for the same transcription factor may coordinate expression of multiple genes. Yeasts such as the industrially important Kluyveromyces marxianus may also display these modes of regulation, but this has not been explored to date. An exploration was done using a complete genome and RNA-seq data from a previous study of the transcriptional response to glucose or xylose as the carbon source in a defined culture medium, and investigating whether the species displays clusters of co-localised differentially expressed genes. Regions of possible subtelomeric silencing were evident, but were non-responsive to the carbon sources tested here. Additionally, glucose or xylose responsive clusters were discovered far from telomeres which contained some of the most significantly differentially expressed genes, encoding enzymes involved in the utilisation of alternative carbon sources such as the industrially important inulinase gene INU1. These clusters contained putative binding sites for the carbon source responsive transcription factors Mig1 and Adr1. Additionally, we investigated the potential contribution of common intergenic regions in co-regulation. Some observations were also made in terms of the evolutionary conservation of these clusters among yeast species and the presence of potential transcriptional insulators at the periphery of these clusters.
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Affiliation(s)
- Du Toit W. P. Schabort
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
- * E-mail:
| | - Stephanus G. Kilian
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - James C. du Preez
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
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7
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Abstract
Peroxisome proliferation involves signal recognition and computation by molecular networks that direct molecular events of gene expression, metabolism, membrane biogenesis, organelle proliferation, protein import, and organelle inheritance. Peroxisome biogenesis in yeast has served as a model system for exploring the regulatory networks controlling this process. Yeast is an outstanding model system to develop tools and approaches to study molecular networks and cellular responses and because the mechanisms of peroxisome biogenesis and key aspects of the transcriptional regulatory networks are remarkably conserved from yeast to humans. In this chapter, we focus on the complex regulatory networks that respond to environmental cues leading to peroxisome assembly and the molecular events of organelle assembly. Ultimately, understanding the mechanisms of the entire peroxisome biogenesis program holds promise for predictive modeling approaches and for guiding rational intervention strategies that could treat human conditions associated with peroxisome function.
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8
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Mast FD, Rachubinski RA, Aitchison JD. Signaling dynamics and peroxisomes. Curr Opin Cell Biol 2015; 35:131-6. [PMID: 26042681 DOI: 10.1016/j.ceb.2015.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 05/09/2015] [Indexed: 02/08/2023]
Abstract
Peroxisomes are remarkably responsive organelles. Their composition, abundance and even their mechanism of biogenesis are influenced strongly by cell type and the environment. This plasticity underlies peroxisomal functions in metabolism and the detoxification of dangerous reactive oxygen species. However, peroxisomes are integrated into the cellular system as a whole such that they communicate intimately with other organelles, control signaling dynamics as in the case of innate immune responses to infectious disease, and contribute to processes as fundamental as longevity. The increasing evidence for peroxisomes having roles in various cellular and organismal functions, combined with their malleability, suggests complex mechanisms operate to control cellular dynamics and the specificity of cellular responses and functions extending well beyond the peroxisome itself. A deeper understanding of the functions of peroxisomes and the mechanisms that control their plasticity could offer opportunities for exploiting changes in peroxisome abundance to control cellular function.
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Affiliation(s)
- Fred D Mast
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, USA; Institute for Systems Biology, Seattle, USA
| | | | - John D Aitchison
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, USA; Institute for Systems Biology, Seattle, USA.
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9
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Srivastava VK, Suneetha KJ, Kaur R. The mitogen-activated protein kinase CgHog1 is required for iron homeostasis, adherence and virulence in Candida glabrata. FEBS J 2015; 282:2142-66. [PMID: 25772226 DOI: 10.1111/febs.13264] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 03/03/2015] [Accepted: 03/10/2015] [Indexed: 01/01/2023]
Abstract
Candida glabrata has emerged as a major fungal pathogen over the last two decades, although our understanding of its survival strategies inside the mammalian host remains rudimentary. An important requirement for survival in vivo is the ability to acquire critical nutrients such as iron from host niches of varied iron content. In the present study, we demonstrate for the first time that C. glabrata cells respond to high external iron levels via activation of two stress-responsive mitogen-activated protein kinases, CgHog1 and CgSlt2, and lack of either kinase results in sensitivity to the high-iron medium. Furthermore, we show that CgHOG1 deletion led to perturbed iron homeostasis (elevated intracellular iron content and high mitochondrial aconitase activity), reduced survival in macrophages and attenuated virulence in the murine model of disseminated candidiasis. Consistently, several genes implicated in iron acquisition and storage displayed deregulated expression in the Cghog1∆ mutant. Genome-wide transcriptional profiling analysis revealed upregulation of genes implicated in DNA repair, RNA processing and autophagy, and downregulation of genes related to cellular respiration and organonitrogen compound metabolism under iron-limiting conditions. In contrast, genes involved in the respiratory electron transport chain were induced under iron-replete conditions. Gene expression microarrays also identified a set of iron-responsive regulon in C. glabrata. Lastly, we present evidence for the iron-regulated expression of the major adhesin-encoding EPA1 gene, decreased histone deacetylase activity in a high-iron environment and increased adherence of iron-surplus-medium-grown C. glabrata cells to epithelial cells. Together, our findings yield novel insights into iron abundance-based regulation of transcriptional and mitogen-activated protein kinase signaling pathways in C. glabrata.
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Affiliation(s)
- Vivek K Srivastava
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India.,Graduate Studies, Manipal University, India
| | - Korivi J Suneetha
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
| | - Rupinder Kaur
- Laboratory of Fungal Pathogenesis, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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10
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Transcriptional response of Saccharomyces cerevisiae to low temperature during wine fermentation. Antonie van Leeuwenhoek 2015; 107:1029-48. [DOI: 10.1007/s10482-015-0395-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/22/2015] [Indexed: 01/31/2023]
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11
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Abstract
Systems cell biology melds high-throughput experimentation with quantitative analysis and modeling to understand many critical processes that contribute to cellular organization and dynamics. Recently, there have been several advances in technology and in the application of modeling approaches that enable the exploration of the dynamic properties of cells. Merging technology and computation offers an opportunity to objectively address unsolved cellular mechanisms, and has revealed emergent properties and helped to gain a more comprehensive and fundamental understanding of cell biology.
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Affiliation(s)
- Fred D Mast
- Seattle Biomedical Research Institute, Seattle, WA 98109 Institute for Systems Biology, Seattle, WA 98109
| | - Alexander V Ratushny
- Seattle Biomedical Research Institute, Seattle, WA 98109 Institute for Systems Biology, Seattle, WA 98109
| | - John D Aitchison
- Seattle Biomedical Research Institute, Seattle, WA 98109 Institute for Systems Biology, Seattle, WA 98109
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12
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Abstract
The term “transcriptional network” refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face. For most yeast TFs, data have been collected on their sequence preferences, in vivo promoter occupancy, and gene expression profiles in deletion mutants. These systematic studies have led to the identification of new regulators of numerous cellular functions and shed light on the overall organization of yeast gene regulation. However, many yeast TFs appear to be inactive under standard laboratory growth conditions, and many of the available data were collected using techniques that have since been improved. Perhaps as a consequence, comprehensive and accurate mapping among TF sequence preferences, promoter binding, and gene expression remains an open challenge. We propose that the time is ripe for renewed systematic efforts toward a complete mapping of yeast transcriptional regulatory mechanisms.
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13
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Abstract
Peroxisomes carry out various oxidative reactions that are tightly regulated to adapt to the changing needs of the cell and varying external environments. Accordingly, they are remarkably fluid and can change dramatically in abundance, size, shape and content in response to numerous cues. These dynamics are controlled by multiple aspects of peroxisome biogenesis that are coordinately regulated with each other and with other cellular processes. Ongoing studies are deciphering the diverse molecular mechanisms that underlie biogenesis and how they cooperate to dynamically control peroxisome utility. These important challenges should lead to an understanding of peroxisome dynamics that can be capitalized upon for bioengineering and the development of therapies to improve human health.
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Affiliation(s)
- Jennifer J Smith
- 1] Seattle Biomedical Research Institute, 307 Westlake Avenue North, 98109-5240, USA. [2] Institute for Systems Biology, 401 Terry Avenue North, Seattle, Washington 98109-5219, USA
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14
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Kueng S, Oppikofer M, Gasser SM. SIR proteins and the assembly of silent chromatin in budding yeast. Annu Rev Genet 2013; 47:275-306. [PMID: 24016189 DOI: 10.1146/annurev-genet-021313-173730] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Saccharomyces cerevisiae provides a well-studied model system for heritable silent chromatin in which a histone-binding protein complex [the SIR (silent information regulator) complex] represses gene transcription in a sequence-independent manner by spreading along nucleosomes, much like heterochromatin in higher eukaryotes. Recent advances in the biochemistry and structural biology of the SIR-chromatin system bring us much closer to a molecular understanding of yeast silent chromatin. Simultaneously, genome-wide approaches have shed light on the biological importance of this form of epigenetic repression. Here, we integrate genetic, structural, and cell biological data into an updated overview of yeast silent chromatin assembly.
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Affiliation(s)
- Stephanie Kueng
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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15
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Wan Y, Zuo X, Zhuo Y, Zhu M, Danziger SA, Zhou Z. The functional role of SUMO E3 ligase Mms21p in the maintenance of subtelomeric silencing in budding yeast. Biochem Biophys Res Commun 2013; 438:746-52. [PMID: 23911609 DOI: 10.1016/j.bbrc.2013.07.096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 07/24/2013] [Indexed: 12/11/2022]
Abstract
In Saccharomyces cerevisiae, subtelomeric silencing is involved in the propagation of Silent Information Regulator (SIR) proteins toward euchromatin. Numerous mechanisms are involved in antagonizing the local spread of Sir-dependent silent chromatin into neighboring euchromatin. Here, we identified a novel role for sumoylation E3 ligase Mms21 in the maintenance of subtelomeric silencing. We found that disruption of E3 ligase activity of Mms21 results in the de-repression of subtelomeric silencing. Deletion of E3 ligase domain of Mms21 led to decreased binding of Sir2p, Sir3p and Sir4 at subtelomeric chromatins and increased H3K4 tri-methylation at telomere-distal euchromatin regions, correlating with increased gene expression in two subtelomeric reporter genes. In addition, a mms21Δsl mutant caused a severe growth defect in combination with htz1Δ deletion and showed an enhanced association of Htz1 with telomere proximal regions. Taken together, our findings suggest an important role of Mms21p; it contributes to subtelomeric silencing during the formation of a heterochromatin boundary.
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Affiliation(s)
- Yakun Wan
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China.
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16
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Schroeder EA, Raimundo N, Shadel GS. Epigenetic silencing mediates mitochondria stress-induced longevity. Cell Metab 2013; 17:954-964. [PMID: 23747251 PMCID: PMC3694503 DOI: 10.1016/j.cmet.2013.04.003] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 02/27/2013] [Accepted: 04/01/2013] [Indexed: 11/30/2022]
Abstract
Reactive oxygen species (ROS) play complex roles in aging, having both damaging effects and signaling functions. Transiently elevating mitochondrial stress, including mitochondrial ROS (mtROS), elicits beneficial responses that extend lifespan. However, these adaptive, longevity-signaling pathways remain poorly understood. We show here that Tel1p and Rad53p, homologs of the mammalian DNA damage response kinases ATM and Chk2, mediate a hormetic mtROS longevity signal that extends yeast chronological lifespan. This pathway senses mtROS in a manner distinct from the nuclear DNA damage response and ultimately imparts longevity by inactivating the histone demethylase Rph1p specifically at subtelomeric heterochromatin, enhancing binding of the silencing protein Sir3p, and repressing subtelomeric transcription. These results demonstrate the existence of conserved mitochondria-to-nucleus stress-signaling pathways that regulate aging through epigenetic modulation of nuclear gene expression.
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Affiliation(s)
- Elizabeth A Schroeder
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Nuno Raimundo
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Gerald S Shadel
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA.
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17
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Abstract
Budding yeast, like other eukaryotes, carries its genetic information on chromosomes that are sequestered from other cellular constituents by a double membrane, which forms the nucleus. An elaborate molecular machinery forms large pores that span the double membrane and regulate the traffic of macromolecules into and out of the nucleus. In multicellular eukaryotes, an intermediate filament meshwork formed of lamin proteins bridges from pore to pore and helps the nucleus reform after mitosis. Yeast, however, lacks lamins, and the nuclear envelope is not disrupted during yeast mitosis. The mitotic spindle nucleates from the nucleoplasmic face of the spindle pole body, which is embedded in the nuclear envelope. Surprisingly, the kinetochores remain attached to short microtubules throughout interphase, influencing the position of centromeres in the interphase nucleus, and telomeres are found clustered in foci at the nuclear periphery. In addition to this chromosomal organization, the yeast nucleus is functionally compartmentalized to allow efficient gene expression, repression, RNA processing, genomic replication, and repair. The formation of functional subcompartments is achieved in the nucleus without intranuclear membranes and depends instead on sequence elements, protein-protein interactions, specific anchorage sites at the nuclear envelope or at pores, and long-range contacts between specific chromosomal loci, such as telomeres. Here we review the spatial organization of the budding yeast nucleus, the proteins involved in forming nuclear subcompartments, and evidence suggesting that the spatial organization of the nucleus is important for nuclear function.
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18
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Role of the repressor Oaf3p in the recruitment of transcription factors and chromatin dynamics during the oleate response. Biochem J 2013; 449:507-17. [PMID: 23088601 DOI: 10.1042/bj20121029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cellular responses to environmental stimuli are mediated by the co-ordinated activity of multiple control mechanisms, which result in the dynamics of cell function. Communication between different levels of regulation is central for this adaptability. The present study focuses on the interplay between transcriptional regulators and chromatin modifiers to co-operatively regulate transcription in response to a fatty acid stimulus. The genes involved in the β-oxidation of fatty acids are highly induced in response to fatty acid exposure by four gene-specific transcriptional regulators, Oaf (oleate-activated transcription factor) 1p, Pip2p (peroxisome induction pathway 2), Oaf3p and Adr1p (alcohol dehydrogenase regulator 1). In the present study, we examine the interplay of these factors with Htz1p (histone variant H2A.Z) in regulating POT1 (peroxisomal oxoacyl thiolase 1) encoding peroxisomal thiolase and PIP2 encoding the autoregulatory oleate-specific transcriptional activator. Temporal resolution of ChIP (chromatin immunoprecipitation) data indicates that Htz1p is required for the timely removal of the transcriptional repressor Oaf3p during oleate induction. Adr1p plays an important role in the assembly of Htz1p-containing nucleosomes on the POT1 and PIP2 promoters. We also investigated the function of the uncharacterized transcriptional inhibitor Oaf3p. Deletion of OAF3 led to faster POT1 mRNA accumulation than in the wild-type. Most impressively, a highly protected nucleosome structure on the POT1 promoter during activation was observed in the OAF3 mutant cells in response to oleate induction.
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Abstract
The mechanisms that maintain the stability of chromosome ends have broad impact on genome integrity in all eukaryotes. Budding yeast is a premier organism for telomere studies. Many fundamental concepts of telomere and telomerase function were first established in yeast and then extended to other organisms. We present a comprehensive review of yeast telomere biology that covers capping, replication, recombination, and transcription. We think of it as yeast telomeres—soup to nuts.
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Abstract
Understanding the genetic mechanisms underlying complex traits is one of the next frontiers in biology. The budding yeast Saccharomyces cerevisiae has become an important model for elucidating the mechanisms that govern natural genetic and phenotypic variation. This success is partially due to its intrinsic biological features, such as the short sexual generation time, high meiotic recombination rate, and small genome size. Precise reverse genetics technologies allow the high throughput manipulation of genetic information with exquisite precision, offering the unique opportunity to experimentally measure the phenotypic effect of genetic variants. Population genomic and phenomic studies have revealed widespread variation between diverged populations, characteristic of man-made environments, as well as geographic clusters of wild strains along with naturally occurring recombinant strains (mosaics). Here, we review these recent studies and provide a perspective on how these previously unappreciated levels of variation can help to bridge our understanding of the genotype-phenotype gap, keeping budding yeast at the forefront of genetic studies. Not only are quantitative trait loci (QTL) being mapped with high resolution down to the nucleotide, for the first time QTLs of modest effect and complex interactions between these QTLs and between QTLs and the environment are being determined experimentally at unprecedented levels using next generation techniques of deep sequencing selected pools of individuals as well as multi-generational crosses.
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Smith JJ, Saleem RA, Aitchison JD. Statistical analysis of dynamic transcriptional regulatory network structure. Methods Mol Biol 2011; 781:337-352. [PMID: 21877289 DOI: 10.1007/978-1-61779-276-2_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Here, we present a detailed method for generating a dynamic transcriptional regulatory network from large-scale chromatin immunoprecipitation data, and functional analysis of participating factors through the identification and characterization of significantly overrepresented multi-input motifs in the network. This is done by visualizing interactive data using a network analysis tool, such as Cytoscape, clustering DNA targets of the transcription factors based on their network topologies, and statistically analyzing each cluster based on its size and properties of its members. These analyses yield testable predictions about the conditional and cooperative functions of the factors. This is a versatile approach that allows the visualization of network architecture on a genome-wide level and is applicable to understanding combinatorial control mechanisms of DNA-binding regulators that conditionally cooperate in a wide variety of biological models.
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