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Luyt NA, de Witt RN, Divol B, Patterton HG, Setati ME, Taillandier P, Bauer FF. Physical cell-cell contact elicits specific transcriptomic responses in wine yeast species. Microbiol Spectr 2024; 12:e0057223. [PMID: 39012115 DOI: 10.1128/spectrum.00572-23] [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: 04/17/2024] [Accepted: 06/21/2024] [Indexed: 07/17/2024] Open
Abstract
Fermenting grape juice provides a habitat for a well-mapped and evolutionarily relevant microbial ecosystem consisting of many natural or inoculated strains of yeasts and bacteria. The molecular nature of many of the ecological interactions within this ecosystem remains poorly understood, with the partial exception of interactions of a metabolic nature such as competition for nutrients and production of toxic metabolites/peptides. Data suggest that physical contact between species plays a significant role in the phenotypic outcome of interspecies interactions. However, the molecular nature of the mechanisms regulating these phenotypes remains unknown. Here, we present a transcriptomic analysis of physical versus metabolic contact between two wine relevant yeast species, Saccharomyces cerevisiae and Lachancea thermotolerans. The data show that these species respond to the physical presence of the other species. In S. cerevisiae, physical contact results in the upregulation of genes involved in maintaining cell wall integrity, cell wall structural components, and genes involved in the production of H2S. In L. thermotolerans, HSP stress response genes were the most significantly upregulated gene family. Both yeasts downregulated genes belonging to the FLO family, some of which play prominent roles in cellular adhesion. qPCR analysis indicates that the expression of some of these genes is regulated in a species-specific manner, suggesting that yeasts adjust gene expression to specific biotic challenges or interspecies interactions. These findings provide fundamental insights into yeast interactions and evolutionary adaptations of these species to the wine ecosystem.IMPORTANCEWithin the wine ecosystem, yeasts are the most relevant contributors to alcoholic fermentation and wine organoleptic characteristics. While some studies have described yeast-yeast interactions during alcoholic fermentation, such interactions remain ill-defined, and little is understood regarding the molecular mechanisms behind many of the phenotypes observed when two or more species are co-cultured. In particular, no study has investigated transcriptional regulation in response to physical interspecies cell-cell contact, as opposed to the generally better understood/characterized metabolic interactions. These data are of direct relevance to our understanding of microbial ecological interactions in general while also creating opportunities to improve ecosystem-based biotechnological applications such as wine fermentation. Furthermore, the presence of competitor species has rarely been considered an evolutionary biotic selection pressure. In this context, the data reveal novel gene functions. This, and further such analysis, is likely to significantly enlarge the genome annotation space.
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Affiliation(s)
- Natasha A Luyt
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Riaan N de Witt
- Centre for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Benoit Divol
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Hugh G Patterton
- Centre for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Mathabatha E Setati
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Patricia Taillandier
- Institut National Polytechnique de Toulouse, Paul Sabatier Université, Laboratoire de Génie Chimique, Université de Toulouse, Toulouse, France
| | - Florian F Bauer
- Department of Viticulture and Oenology, South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, Western Cape, South Africa
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2
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Wang D, Zeng N, Li C, Li Z, Zhang N, Li B. Fungal biofilm formation and its regulatory mechanism. Heliyon 2024; 10:e32766. [PMID: 38988529 PMCID: PMC11233959 DOI: 10.1016/j.heliyon.2024.e32766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 06/07/2024] [Accepted: 06/08/2024] [Indexed: 07/12/2024] Open
Abstract
Fungal biofilm is a microbial community composed of fungal cells and extracellular polymeric substances (EPS). In recent years, fungal biofilms have played an increasingly important role in many fields. However, there are few studies on fungal biofilms and their related applications and development are still far from enough. Therefore, this review summarizes the composition and function of EPS in fungal biofilms, and improves and refines the formation process of fungal biofilms according to the latest viewpoints. Moreover, based on the study of Saccharomyces cerevisiae and Candida albicans, this review summarizes the gene regulation network of fungal biofilm synthesis, which is crucial for systematically understanding the molecular mechanism of fungal biofilm formation. It is of great significance to further develop effective methods at the molecular level to control harmful biofilms or enhance and regulate the formation of beneficial biofilms. Finally, the quorum sensing factors and mixed biofilms formed by fungi in the current research of fungal biofilms are summarized. These results will help to deepen the understanding of the formation process and internal regulation mechanism of fungal biofilm, provide reference for the study of EPS composition and structure, formation, regulation, group behavior and mixed biofilm formation of other fungal biofilms, and provide strategies and theoretical basis for the control, development and utilization of fungal biofilms.
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Affiliation(s)
- Dandan Wang
- College of Land and Environment, Shenyang Agricultural University, Shenyang, 110866, PR China
| | - Nan Zeng
- College of Land and Environment, Shenyang Agricultural University, Shenyang, 110866, PR China
| | - Chunji Li
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, PR China
- Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China, Ministry of Agriculture and Rural Affairs, Guangzhou, 510225, PR China
- College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, PR China
| | - Zijing Li
- College of Food Science, Shenyang Agricultural University, Shenyang, 110866, PR China
| | - Ning Zhang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, PR China
| | - Bingxue Li
- College of Land and Environment, Shenyang Agricultural University, Shenyang, 110866, PR China
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3
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Jethmalani Y, Tran K, Negesse MY, Sun W, Ramos M, Jaiswal D, Jezek M, Amos S, Garcia EJ, Park D, Green EM. Set4 regulates stress response genes and coordinates histone deacetylases within yeast subtelomeres. Life Sci Alliance 2021; 4:e202101126. [PMID: 34625508 PMCID: PMC8507492 DOI: 10.26508/lsa.202101126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 12/25/2022] Open
Abstract
The yeast chromatin protein Set4 is a member of the Set3-subfamily of SET domain proteins which play critical roles in the regulation of gene expression in diverse developmental and environmental contexts. We previously reported that Set4 promotes survival during oxidative stress and regulates expression of stress response genes via stress-dependent chromatin localization. In this study, global gene expression analysis and investigation of histone modification status identified a role for Set4 in maintaining gene repressive mechanisms within yeast subtelomeres under both normal and stress conditions. We show that Set4 works in a partially overlapping pathway to the SIR complex and the histone deacetylase Rpd3 to maintain proper levels of histone acetylation and expression of stress response genes encoded in subtelomeres. This role for Set4 is particularly critical for cells under hypoxic conditions, where the loss of Set4 decreases cell fitness and cell wall integrity. These findings uncover a new regulator of subtelomeric chromatin that is key to stress defense pathways and demonstrate a function for Set4 in regulating repressive, heterochromatin-like environments.
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Affiliation(s)
- Yogita Jethmalani
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Khoa Tran
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Maraki Y Negesse
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Winny Sun
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Mark Ramos
- Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Deepika Jaiswal
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Meagan Jezek
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Shandon Amos
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Eric Joshua Garcia
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
| | - DoHwan Park
- Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Erin M Green
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, USA
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4
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Vallabhaneni AR, Kabashi M, Haymowicz M, Bhatt K, Wayman V, Ahmed S, Conrad-Webb H. HSF1 induces RNA polymerase II synthesis of ribosomal RNA in S. cerevisiae during nitrogen deprivation. Curr Genet 2021; 67:937-951. [PMID: 34363098 PMCID: PMC8594204 DOI: 10.1007/s00294-021-01197-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/29/2022]
Abstract
The resource intensive process of accurate ribosome synthesis is essential for cell viability in all organisms. Ribosome synthesis regulation centers on RNA polymerase I (pol I) transcription of a 35S rRNA precursor that is processed into the mature 18S, 5.8S and 25S rRNAs. During nutrient deprivation or stress, pol I synthesis of rRNA is dramatically reduced. Conversely, chronic stress such as mitochondrial dysfunction induces RNA polymerase II (pol II) to transcribe functional rRNA using an evolutionarily conserved cryptic pol II rDNA promoter suggesting a universal phenomenon. However, this polymerase switches and its role in regulation of rRNA synthesis remain unclear. In this paper, we demonstrate that extended nitrogen deprivation induces the polymerase switch via components of the environmental stress response. We further show that the switch is repressed by Sch9 and activated by the stress kinase Rim15. Like stress-induced genes, the switch requires not only pol II transcription machinery, including the mediator, but also requires the HDAC, Rpd3 and stress transcription factor Hsf1. The current work shows that the constitutive allele, Hsf1PO4* displays elevated levels of induction in non-stress conditions while binding to a conserved site in the pol II rDNA promoter upstream of the pol I promoter. Whether the polymerase switch serves to provide rRNA when pol I transcription is inhibited or fine-tunes pol I initiation via RNA interactions is yet to be determined. Identifying the underlying mechanism for this evolutionary conserved phenomenon will help understand the mechanism of pol II rRNA synthesis and its role in stress adaptation.
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Affiliation(s)
- Arjuna Rao Vallabhaneni
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA
| | - Merita Kabashi
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA
| | - Matt Haymowicz
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA
| | - Kushal Bhatt
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA.,Department of Bioinformatics, University of Texas Southwestern, 5323 Harry Hines Blvd., Dallas, Texas, 75390, USA
| | - Violet Wayman
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA
| | - Shazia Ahmed
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA
| | - Heather Conrad-Webb
- Department of Biology, Texas Woman's University, 304 Administration Dr., Denton, TX, 76204, USA.
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5
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Sauty SM, Shaban K, Yankulov K. Gene repression in S. cerevisiae-looking beyond Sir-dependent gene silencing. Curr Genet 2020; 67:3-17. [PMID: 33037902 DOI: 10.1007/s00294-020-01114-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 01/09/2023]
Abstract
Gene silencing by the SIR (Silent Information Region) family of proteins in S. cerevisiae has been extensively studied and has served as a founding paradigm for our general understanding of gene repression and its links to histone deacetylation and chromatin structure. In recent years, our understanding of other mechanisms of gene repression in S.cerevisiae was significantly advanced. In this review, we focus on such Sir-independent mechanisms of gene repression executed by various Histone Deacetylases (HDACs) and Histone Methyl Transferases (HMTs). We focus on the genes regulated by these enzymes and their known mechanisms of action. We describe the cooperation and redundancy between HDACs and HMTs, and their involvement in gene repression by non-coding RNAs or by their non-histone substrates. We also propose models of epigenetic transmission of the chromatin structures produced by these enzymes and discuss these in the context of gene repression phenomena in other organisms. These include the recycling of the epigenetic marks imposed by HMTs or the recycling of the complexes harboring HDACs.
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Affiliation(s)
- Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada.
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6
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Nuclear receptor corepressors in intellectual disability and autism. Mol Psychiatry 2020; 25:2220-2236. [PMID: 32034290 PMCID: PMC7842082 DOI: 10.1038/s41380-020-0667-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/24/2019] [Accepted: 01/28/2020] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) is characterized by neurocognitive dysfunctions, such as impaired social interaction and language learning. Gene-environment interactions have a pivotal role in ASD pathogenesis. Nuclear receptor corepressors (NCORs) are transcription co-regulators physically associated with histone deacetylases (HDACs) and many known players in ASD etiology such as transducin β-like 1 X-linked receptor 1 and methyl-CpG binding protein 2. The epigenome-modifying NCOR complex is sensitive to many ASD risk factors, including HDAC inhibitor valproic acid and a variety of endocrine factors, xenobiotic chemicals, or metabolites that can directly bind to multiple nuclear receptors. Here, we review recent studies of NCORs in neurocognition using animal models and human genetics approaches. We discuss functional interplays between NCORs and other known players in ASD etiology. It is conceivable that the NCOR complex may bridge the in utero environmental risk factors of ASD with epigenetic remodeling and can serve as a converging point for many gene-environment interactions in the pathogenesis of ASD and intellectual disability.
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7
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Joshua IM, Höfken T. From Lipid Homeostasis to Differentiation: Old and New Functions of the Zinc Cluster Proteins Ecm22, Upc2, Sut1 and Sut2. Int J Mol Sci 2017; 18:ijms18040772. [PMID: 28379181 PMCID: PMC5412356 DOI: 10.3390/ijms18040772] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/27/2022] Open
Abstract
Zinc cluster proteins are a large family of transcriptional regulators with a wide range of biological functions. The zinc cluster proteins Ecm22, Upc2, Sut1 and Sut2 have initially been identified as regulators of sterol import in the budding yeast Saccharomyces cerevisiae. These proteins also control adaptations to anaerobic growth, sterol biosynthesis as well as filamentation and mating. Orthologs of these zinc cluster proteins have been identified in several species of Candida. Upc2 plays a critical role in antifungal resistance in these important human fungal pathogens. Upc2 is therefore an interesting potential target for novel antifungals. In this review we discuss the functions, mode of actions and regulation of Ecm22, Upc2, Sut1 and Sut2 in budding yeast and Candida.
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Affiliation(s)
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK.
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8
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Bae NS, Seberg AP, Carroll LP, Swanson MJ. Identification of Genes in Saccharomyces cerevisiae that Are Haploinsufficient for Overcoming Amino Acid Starvation. G3 (BETHESDA, MD.) 2017; 7:1061-1084. [PMID: 28209762 PMCID: PMC5386856 DOI: 10.1534/g3.116.037416] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/11/2017] [Indexed: 12/17/2022]
Abstract
The yeast Saccharomyces cerevisiae responds to amino acid deprivation by activating a pathway conserved in eukaryotes to overcome the starvation stress. We have screened the entire yeast heterozygous deletion collection to identify strains haploinsufficient for growth in the presence of sulfometuron methyl, which causes starvation for isoleucine and valine. We have discovered that cells devoid of MET15 are sensitive to sulfometuron methyl, and loss of heterozygosity at the MET15 locus can complicate screening the heterozygous deletion collection. We identified 138 cases of loss of heterozygosity in this screen. After eliminating the issues of the MET15 loss of heterozygosity, strains isolated from the collection were retested on sulfometuron methyl. To determine the general effect of the mutations for a starvation response, SMM-sensitive strains were tested for the ability to grow in the presence of canavanine, which induces arginine starvation, and strains that were MET15 were also tested for growth in the presence of ethionine, which causes methionine starvation. Many of the genes identified in our study were not previously identified as starvation-responsive genes, including a number of essential genes that are not easily screened in a systematic way. The genes identified span a broad range of biological functions, including many involved in some level of gene expression. Several unnamed proteins have also been identified, giving a clue as to possible functions of the encoded proteins.
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Affiliation(s)
- Nancy S Bae
- Department of Biochemistry, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona 85308
| | - Andrew P Seberg
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295
| | - Leslie P Carroll
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, Georgia 31207
| | - Mark J Swanson
- Department of Biochemistry, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona 85308
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, Georgia 31207
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9
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Sequence elements upstream of the core promoter are necessary for full transcription of the capsule gene operon in Streptococcus pneumoniae strain D39. Infect Immun 2015; 83:1957-72. [PMID: 25733517 DOI: 10.1128/iai.02944-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/16/2015] [Indexed: 02/05/2023] Open
Abstract
Streptococcus pneumoniae is a major bacterial pathogen in humans. Its polysaccharide capsule is a key virulence factor that promotes bacterial evasion of human phagocytic killing. While S. pneumoniae produces at least 94 antigenically different types of capsule, the genes for biosynthesis of almost all capsular types are arranged in the same locus. The transcription of the capsular polysaccharide (cps) locus is not well understood. This study determined the transcriptional features of the cps locus in the type 2 virulent strain D39. The initial analysis revealed that the cps genes are cotranscribed from a major transcription start site at the -25 nucleotide (G) upstream of cps2A, the first gene in the locus. Using unmarked chromosomal truncations and a luciferase-based transcriptional reporter, we showed that the full transcription of the cps genes not only depends on the core promoter immediately upstream of cps2A, but also requires additional elements upstream of the core promoter, particularly a 59-bp sequence immediately upstream of the core promoter. Unmarked deletions of these promoter elements in the D39 genome also led to significant reduction in CPS production and virulence in mice. Lastly, common cps gene (cps2ABCD) mutants did not show significant abnormality in cps transcription, although they produced significantly less CPS, indicating that the CpsABCD proteins are involved in the encapsulation of S. pneumoniae in a posttranscriptional manner. This study has yielded important information on the transcriptional characteristics of the cps locus in S. pneumoniae.
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10
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Lee KW, Chen PW, Yu SM. Metabolic adaptation to sugar/O2 deficiency for anaerobic germination and seedling growth in rice. PLANT, CELL & ENVIRONMENT 2014; 37:2234-44. [PMID: 24575721 DOI: 10.1111/pce.12311] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/12/2014] [Accepted: 02/16/2014] [Indexed: 05/20/2023]
Abstract
Rice is characterized by a broad range of metabolic and morphological adaptations to flooding, such as germination and mobilization of stored nutrients under submergence until seedlings reach the water surface to carry out photosynthesis, and sustainable growth of mature plants for long durations under partial submergence. The underlying mechanisms of the molecular basis of adaptation to anaerobic germination and seedling growth in rice are being uncovered. Induction of an ensemble of hydrolases to mobilize endosperm nutrient reserves is one of the key factors for successful germination and coleoptile elongation in rice under submergence. To compensate for reduced efficiency of Tricarboxylic Acid cycle and oxidative respiration in mitochondria under O2 deficient conditions, α-amylases play a central role in the hydrolysis of starch to provide sugar substrates for glycolysis and alcohol fermentation for generating ATP. We review the progress on the molecular mechanism regulating α-amylase expression that involves the integration of signals generated by the hormone gibberellin (GA), sugar starvation and O2 deprivation that results in germination and sustainable seedling growth in rice under anaerobic conditions. Comparisons are also made between dicots and monocots for the molecular mechanism of induction of genes involved in alcohol fermentation and sugar/O2 deficiency sensing system.
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Affiliation(s)
- Kuo-Wei Lee
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan
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11
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Ansari SA, Paul E, Sommer S, Lieleg C, He Q, Daly AZ, Rode KA, Barber WT, Ellis LC, LaPorta E, Orzechowski AM, Taylor E, Reeb T, Wong J, Korber P, Morse RH. Mediator, TATA-binding protein, and RNA polymerase II contribute to low histone occupancy at active gene promoters in yeast. J Biol Chem 2014; 289:14981-95. [PMID: 24727477 DOI: 10.1074/jbc.m113.529354] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transcription by RNA polymerase II (Pol II) in eukaryotes requires the Mediator complex, and often involves chromatin remodeling and histone eviction at active promoters. Here we address the role of Mediator in recruitment of the Swi/Snf chromatin remodeling complex and its role, along with components of the preinitiation complex (PIC), in histone eviction at inducible and constitutively active promoters in the budding yeast Saccharomyces cerevisiae. We show that recruitment of the Swi/Snf chromatin remodeling complex to the induced CHA1 promoter, as well as its association with several constitutively active promoters, depends on the Mediator complex but is independent of Mediator at the induced MET2 and MET6 genes. Although transcriptional activation and histone eviction at CHA1 depends on Swi/Snf, Swi/Snf recruitment is not sufficient for histone eviction at the induced CHA1 promoter. Loss of Swi/Snf activity does not affect histone occupancy of several constitutively active promoters; in contrast, higher histone occupancy is seen at these promoters in Mediator and PIC component mutants. We propose that an initial activator-dependent, nucleosome remodeling step allows PIC components to outcompete histones for occupancy of promoter sequences. We also observe reduced promoter association of Mediator and TATA-binding protein in a Pol II (rpb1-1) mutant, indicating mutually cooperative binding of these components of the transcription machinery and indicating that it is the PIC as a whole whose binding results in stable histone eviction.
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Affiliation(s)
- Suraiya A Ansari
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Emily Paul
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Sebastian Sommer
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Corinna Lieleg
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Qiye He
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
| | - Alexandre Z Daly
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Kara A Rode
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Wesley T Barber
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Laura C Ellis
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Erika LaPorta
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
| | - Amanda M Orzechowski
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Emily Taylor
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Tanner Reeb
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Jason Wong
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Philipp Korber
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Randall H Morse
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
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12
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Zambuzzi-Carvalho PF, Tomazett PK, Santos SC, Ferri PH, Borges CL, Martins WS, de Almeida Soares CM, Pereira M. Transcriptional profile of Paracoccidioides induced by oenothein B, a potential antifungal agent from the Brazilian Cerrado plant Eugenia uniflora. BMC Microbiol 2013; 13:227. [PMID: 24119145 PMCID: PMC3852496 DOI: 10.1186/1471-2180-13-227] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/01/2013] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The compound oenothein B (OenB), which is isolated from the leaves of Eugenia uniflora, a Brazilian Cerrado plant, interferes with Paracoccidioides yeast cell morphology and inhibits 1,3-β-D-glucan synthase (PbFKS1) transcript accumulation, which is involved in cell wall synthesis. In this work we examined the gene expression changes in Paracoccidioides yeast cells following OenB treatment in order to investigate the adaptive cellular responses to drug stress. RESULTS We constructed differential gene expression libraries using Representational Difference Analysis (RDA) of Paracoccidioides yeast cells treated with OenB for 90 and 180 min. Treatment for 90 min resulted in the identification of 463 up-regulated expressed sequences tags (ESTs) and 104 down-regulated ESTs. For the 180 min treatment 301 up-regulated ESTs and 143 down-regulated were identified. Genes involved in the cell wall biosynthesis, such as GLN1, KRE6 and FKS1, were found to be regulated by OenB. Infection experiments in macrophages corroborated the in vitro results. Fluorescence microscopy showed increased levels of chitin in cells treated with OenB. The carbohydrate polymer content of the cell wall of the fungus was also evaluated, and the results corroborated with the transcriptional data. Several other genes, such as those involved in a variety of important cellular processes (i.e., membrane maintenance, stress and virulence) were found to be up-regulated in response to OenB treatment. CONCLUSIONS The exposure of Paracoccidioides to OenB resulted in a complex altered gene expression profile. Some of the changes may represent specific adaptive responses to this compound in this important pathogenic fungus.
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Affiliation(s)
- Patrícia Fernanda Zambuzzi-Carvalho
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Patrícia Kott Tomazett
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Suzana Costa Santos
- Laboratório de Bioatividade Molecular, Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Pedro Henrique Ferri
- Laboratório de Bioatividade Molecular, Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Clayton Luiz Borges
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | | | - Célia Maria de Almeida Soares
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Maristela Pereira
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
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13
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The yeast Snt2 protein coordinates the transcriptional response to hydrogen peroxide-mediated oxidative stress. Mol Cell Biol 2013; 33:3735-48. [PMID: 23878396 DOI: 10.1128/mcb.00025-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Regulation of gene expression is a vital part of the cellular stress response, yet the full set of proteins that orchestrate this regulation remains unknown. Snt2 is a Saccharomyces cerevisiae protein whose function has not been well characterized that was recently shown to associate with Ecm5 and the Rpd3 deacetylase. Here, we confirm that Snt2, Ecm5, and Rpd3 physically associate. We then demonstrate that cells lacking Rpd3 or Snt2 are resistant to hydrogen peroxide (H2O2)-mediated oxidative stress and use chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) to show that Snt2 and Ecm5 recruit Rpd3 to a small number of promoters and in response to H2O2, colocalize independently of Rpd3 to the promoters of stress response genes. By integrating ChIP-seq and expression analyses, we identify target genes that require Snt2 for proper expression after H2O2. Finally, we show that cells lacking Snt2 are also resistant to nutrient stress imparted by the TOR (target of rapamycin) pathway inhibitor rapamycin and identify a common set of genes targeted by Snt2 and Ecm5 in response to both H2O2 and rapamycin. Our results establish a function for Snt2 in regulating transcription in response to oxidative stress and suggest Snt2 may also function in multiple stress pathways.
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14
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Systematic measurement of transcription factor-DNA interactions by targeted mass spectrometry identifies candidate gene regulatory proteins. Proc Natl Acad Sci U S A 2013; 110:3645-50. [PMID: 23388641 DOI: 10.1073/pnas.1216918110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Regulation of gene expression involves the orchestrated interaction of a large number of proteins with transcriptional regulatory elements in the context of chromatin. Our understanding of gene regulation is limited by the lack of a protein measurement technology that can systematically detect and quantify the ensemble of proteins associated with the transcriptional regulatory elements of specific genes. Here, we introduce a set of selected reaction monitoring (SRM) assays for the systematic measurement of 464 proteins with known or suspected roles in transcriptional regulation at RNA polymerase II transcribed promoters in Saccharomyces cerevisiae. Measurement of these proteins in nuclear extracts by SRM permitted the reproducible quantification of 42% of the proteins over a wide range of abundances. By deploying the assay to systematically identify DNA binding transcriptional regulators that interact with the environmentally regulated FLO11 promoter in cell extracts, we identified 15 regulators that bound specifically to distinct regions along ∼600 bp of the regulatory sequence. Importantly, the dataset includes a number of regulators that have been shown to either control FLO11 expression or localize to these regulatory regions in vivo. We further validated the utility of the approach by demonstrating that two of the SRM-identified factors, Mot3 and Azf1, are required for proper FLO11 expression. These results demonstrate the utility of SRM-based targeted proteomics to guide the identification of gene-specific transcriptional regulators.
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15
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H3K4 methyltransferase Set1 is involved in maintenance of ergosterol homeostasis and resistance to Brefeldin A. Proc Natl Acad Sci U S A 2013; 110:E1016-25. [PMID: 23382196 DOI: 10.1073/pnas.1215768110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Set1 is a conserved histone H3 lysine 4 (H3K4) methyltransferase that exists as a multisubunit complex. Although H3K4 methylation is located on many actively transcribed genes, few studies have established a direct connection showing that loss of Set1 and H3K4 methylation results in a phenotype caused by disruption of gene expression. In this study, we determined that cells lacking Set1 or Set1 complex members that disrupt H3K4 methylation have a growth defect when grown in the presence of the antifungal drug Brefeldin A (BFA), indicating that H3K4 methylation is needed for BFA resistance. To determine the role of Set1 in BFA resistance, we discovered that Set1 is important for the expression of genes in the ergosterol biosynthetic pathway, including the rate-limiting enzyme HMG-CoA reductase. Consequently, deletion of SET1 leads to a reduction in HMG-CoA reductase protein and total cellular ergosterol. In addition, the lack of Set1 results in an increase in the expression of DAN1 and PDR11, two genes involved in ergosterol uptake. The increase in expression of uptake genes in set1Δ cells allows sterols such as cholesterol and ergosterol to be actively taken up under aerobic conditions. Interestingly, when grown in the presence of ergosterol set1Δ cells become resistant to BFA, indicating that proper ergosterol levels are needed for antifungal drug resistance. These data show that H3K4 methylation impacts gene expression and output of a biologically and medically relevant pathway and determines why cells lacking H3K4 methylation have antifungal drug sensitivity.
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16
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Short MK, Hallett JP, Tar K, Dange T, Schmidt M, Moir R, Willis IM, Jubinsky PT. The yeast magmas ortholog pam16 has an essential function in fermentative growth that involves sphingolipid metabolism. PLoS One 2012; 7:e39428. [PMID: 22808036 PMCID: PMC3393719 DOI: 10.1371/journal.pone.0039428] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Accepted: 05/22/2012] [Indexed: 01/06/2023] Open
Abstract
Magmas is a growth factor responsive gene encoding an essential mitochondrial protein in mammalian cells. Pam16, the Magmas ortholog in Saccharomyces cerevisiae, is a component of the presequence translocase-associated motor. A temperature-sensitive allele (pam16-I61N) was used to query an array of non-essential gene-deletion strains for synthetic genetic interactions. The pam16-I61N mutation at ambient temperature caused synthetic lethal or sick phenotypes with genes involved in lipid metabolism, perixosome synthesis, histone deacetylation and mitochondrial protein import. The gene deletion array was also screened for suppressors of the pam16-I61N growth defect to identify compensatory pathways. Five suppressor genes were identified (SUR4, ISC1, IPT1, SKN1, and FEN1) and all are involved in sphingolipid metabolism. pam16-I61N cells cultured in glucose at non-permissive temperatures resulted in rapid growth inhibition and G1 cell cycle arrest, but cell viability was maintained. Altered mitochondria morphology, reduced peroxisome induction in glycerol/ethanol and oleate, and changes in the levels of several sphingolipids including C18 alpha-hydroxy-phytoceramide, were also observed in the temperature sensitive strain. Deletion of SUR4, the strongest suppressor, reversed the temperature sensitive fermentative growth defect, the morphological changes and the elevated levels of C18 alpha-hydroxy phytoceramide in pam16-I61N. Deletion of the other four suppressor genes had similar effects on C18 alpha-hydroxy-phytoceramide levels and restored proliferation to the pam16-I61N strain. In addition, pam16-I61N inhibited respiratory growth, likely by reducing cardiolipin, which is essential for mitochondrial function. Our results suggest that the pleiotropic effects caused by impaired Pam16/Magmas function are mediated in part by changes in lipid metabolism.
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Affiliation(s)
- Mary K Short
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
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17
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Chromatin modulation at the FLO11 promoter of Saccharomyces cerevisiae by HDAC and Swi/Snf complexes. Genetics 2012; 191:791-803. [PMID: 22542969 DOI: 10.1534/genetics.112.140301] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cell adhesion and biofilm formation are critical processes in the pathogenicity of fungi and are mediated through a family of adhesin proteins conserved throughout yeasts and fungi. In Saccharomyces cerevisiae, Flo11 is the main adhesin involved in cell adhesion and biofilm formation, making the study of its function and regulation in this nonpathogenic budding yeast highly relevant. The S. cerevisiae FLO11 gene is driven by a TATA-box-containing promoter that is regulated through one of the longest regulatory upstream regions (3 kb) in yeast. We reported recently that two chromatin cofactor complexes, the Rpd3L deacetylase and the Swi/Snf chromatin-remodeling complexes, contribute significantly to the regulation of FLO11. Here, we analyze directly how these complexes impact on FLO11 promoter chromatin structure and dissect further the interplay between histone deacetylases, chromatin remodeling, and the transcriptional repressor Sfl1. We show that the regulation of chromatin structure represents an important layer of control in the highly complex regulation of the FLO11 promoter.
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18
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The Rpd3 core complex is a chromatin stabilization module. Curr Biol 2011; 22:56-63. [PMID: 22177115 DOI: 10.1016/j.cub.2011.11.042] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/21/2011] [Accepted: 11/21/2011] [Indexed: 11/22/2022]
Abstract
The S. cerevisiae Rpd3 large (Rpd3L) and small (Rpd3S) histone deacetylase (HDAC) complexes are prototypes for understanding transcriptional repression in eukaryotes [1]. The current view is that they function by deacetylating chromatin, thereby limiting accessibility of transcriptional factors to the underlying DNA. However, an Rpd3 catalytic mutant retains substantial repression capability when targeted to a promoter as a LexA fusion protein [2]. We investigated the HDAC-independent properties of the Rpd3 complexes biochemically and discovered a chaperone function, which promotes histone deposition onto DNA, and a novel activity, which prevents nucleosome eviction but not remodeling mediated by the ATP-dependent RSC complex. These HDAC-independent activities inhibit Pol II transcription on a nucleosomal template. The functions of the endogenous Rpd3 complexes can be recapitulated with recombinant Rpd3 core complex comprising Sin3, Rpd3, and Ume1. To test the hypothesis that Rpd3 contributes to chromatin stabilization in vivo, we measured histone H3 density genomewide and found that it was reduced at promoters in an Rpd3 deletion mutant but partially restored in a catalytic mutant. Importantly, the effects on H3 density are most apparent on RSC-enriched genes [3]. Our data suggest that the Rpd3 core complex could contribute to repression via a novel nucleosome stabilization function.
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19
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Alteration of ethanol tolerance caused by the deficiency in the genes associated with histone deacetylase complex in budding yeast. Biosci Biotechnol Biochem 2011; 75:1829-31. [PMID: 21897015 DOI: 10.1271/bbb.110232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Upon exposure to 8% ethanol, survival and growth of yeast strains deficient in histone deacetylase complex genes was examined. Of the 18 mutants tested, the Δsir3 and Δsir4 strains showed higher resistance to ethanol, while the Δrco1, Δhos3, Δhda2, and Δhst1 strains were more sensitive than the wild type. Furthermore, these ethanol-resistant patterns varied under aerobic and anaerobic culture conditions.
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20
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Lu Y, Su C, Wang A, Liu H. Hyphal development in Candida albicans requires two temporally linked changes in promoter chromatin for initiation and maintenance. PLoS Biol 2011; 9:e1001105. [PMID: 21811397 PMCID: PMC3139633 DOI: 10.1371/journal.pbio.1001105] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 05/31/2011] [Indexed: 12/21/2022] Open
Abstract
Phenotypic plasticity is common in development. For Candida albicans, the most common cause of invasive fungal infections in humans, morphological plasticity is its defining feature and is critical for its pathogenesis. Unlike other fungal pathogens that exist primarily in either yeast or hyphal forms, C. albicans is able to switch reversibly between yeast and hyphal growth forms in response to environmental cues. Although many regulators have been found involved in hyphal development, the mechanisms of regulating hyphal development and plasticity of dimorphism remain unclear. Here we show that hyphal development involves two sequential regulations of the promoter chromatin of hypha-specific genes. Initiation requires a rapid but temporary disappearance of the Nrg1 transcriptional repressor of hyphal morphogenesis via activation of the cAMP-PKA pathway. Maintenance requires promoter recruitment of Hda1 histone deacetylase under reduced Tor1 (target of rapamycin) signaling. Hda1 deacetylates a subunit of the NuA4 histone acetyltransferase module, leading to eviction of the NuA4 acetyltransferase module and blockage of Nrg1 access to promoters of hypha-specific genes. Promoter recruitment of Hda1 for hyphal maintenance happens only during the period when Nrg1 is gone. The sequential regulation of hyphal development by the activation of the cAMP-PKA pathway and reduced Tor1 signaling provides a molecular mechanism for plasticity of dimorphism and how C. albicans adapts to the varied host environments in pathogenesis. Such temporally linked regulation of promoter chromatin by different signaling pathways provides a unique mechanism for integrating multiple signals during development and cell fate specification. Many organisms are able to change their phenotype in response to changes in the environment, a phenomenon referred to as plasticity. Candida albicans, a major opportunistic fungal pathogen of humans, can undergo reversible morphological changes between yeast (spherical) and hyphal (filamentous) forms of growth in response to environmental cues. This morphological plasticity is essential for its pathogenesis and survival in its hosts. In this study, we show that hyphal development is initiated and maintained by two major nutrient-sensing cellular growth pathways that act by removing the inhibition provided by the transcriptional repressor Nrg1. While initiation requires a rapid but temporary disappearance of Nrg1 via activation of the cAMP-dependent protein kinase A pathway, maintenance requires the recruitment to promoters of the Hda1 histone deacetylase under conditions of reduced signaling by the target of rapamycin (TOR) kinase, leading to chromatin remodeling that blocks Nrg1 access to the promoters of hypha-specific genes. We observed that recruitment of Hda1 to promoters happens only during the time window when Nrg1 is absent. Such temporally linked regulation of promoter chromatin by different signaling pathways provides a unique mechanism for integrating multiple signals in the regulation of gene expression and phenotypic plasticity during development and cell fate specification.
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Affiliation(s)
- Yang Lu
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
| | - Chang Su
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
| | - Allen Wang
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California, United States of America
- * E-mail:
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21
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Grahl N, Cramer RA. Regulation of hypoxia adaptation: an overlooked virulence attribute of pathogenic fungi? Med Mycol 2010; 48:1-15. [PMID: 19462332 DOI: 10.3109/13693780902947342] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Over the past two decades, the incidence of fungal infections has dramatically increased. This is primarily due to increases in the population of immunocompromised individuals attributed to the HIV/AIDS pandemic and immunosuppression therapies associated with organ transplantation, cancer, and other diseases where new immunomodulatory therapies are utilized. Significant advances have been made in understanding how fungi cause disease, but clearly much remains to be learned about the pathophysiology of these often lethal infections. Fungal pathogens face numerous environmental challenges as they colonize and infect mammalian hosts. Regardless of a pathogen's complexity, its ability to adapt to environmental changes is critical for its survival and ability to cause disease. For example, at sites of fungal infections, the significant influx of immune effector cells and the necrosis of tissue by the invading pathogen generate hypoxic microenvironments to which both the pathogen and host cells must adapt in order to survive. However, our current knowledge of how pathogenic fungi adapt to and survive in hypoxic conditions during fungal pathogenesis is limited. Recent studies have begun to observe that the ability to adapt to various levels of hypoxia is an important component of the virulence arsenal of pathogenic fungi. In this review, we focus on known oxygen sensing mechanisms that non-pathogenic and pathogenic fungi utilize to adapt to hypoxic microenvironments and their possible relation to fungal virulence.
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Affiliation(s)
- Nora Grahl
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, Montana, USA
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22
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Tan RZ, van Oudenaarden A. Transcript counting in single cells reveals dynamics of rDNA transcription. Mol Syst Biol 2010; 6:358. [PMID: 20393578 PMCID: PMC2872610 DOI: 10.1038/msb.2010.14] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 02/09/2010] [Indexed: 11/09/2022] Open
Abstract
Fluorescence in-situ hybridization (FISH) technique allows the detection of single RNA molecules in individual yeast cells. We use this method complemented with theoretical modeling to determine the rate of switching from OFF to ON (activation rate) and the average number of RNA molecules produced during each transcriptional burst (burst size). Switching of the rDNA repeats between the inactive non-transcribing state and the active transcribing state occurs rapidly. On average, it takes an inactive repeat 8 2 min to transit to the active state. As cell density increases, mean rRNA transcriptional activity decreases. This is due to the decreases in burst size. The activation rate remains constant. In the rpd3 strain, activation rate doubles and the burst size is half that of wild-type cells in log-phase. This effect of Rpd3 on activation rate is independent of cell density. As the cell density increases, the burst size of the rpd3 strain becomes similar to that of wild-type cells.
Most eukaryotes contain many tandem repeats of ribosomal RNA genes of which only a subset is transcribed at any given time. Current biochemical methods allow for the determination of the fraction of transcribing repeats (ON) versus non-transcribing repeats (OFF) but do not provide any dynamical information and obscure any transcription activity at the single-cell level. Here, we use a fluorescence in situ hybridization (FISH) technique that allows the detection of single-RNA molecules in individual yeast cells. We use this method complemented with theoretical modeling to determine the rate of switching from OFF to ON (activation rate) and the average number of RNA molecules produced during each transcriptional burst (burst size). We explore how these two variables change in mutants and different growth conditions, and show that this method resolves changes in these two variables even when the average rDNA expression is unaltered. These phenotypic changes could not have been detected by traditional biochemical assays.
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Affiliation(s)
- Rui Zhen Tan
- Harvard University Graduate Biophysics Program, Harvard Medical School, Boston, MA, USA
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23
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Transcriptional activation of the general amino acid permease gene per1 by the histone deacetylase Clr6 Is regulated by Oca2 kinase. Mol Cell Biol 2010; 30:3396-410. [PMID: 20404084 DOI: 10.1128/mcb.00971-09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Expression of nitrogen metabolism genes is regulated by the quality of the nitrogen supply. Here, we describe a mechanism for the transcriptional regulation of the general amino acid permease gene per1 in Schizosaccharomyces pombe. We show that when ammonia is used as the nitrogen source, low levels of per1 are transcribed and histones in the coding and surrounding regions of per1 are acetylated. In the presence of proline, per1 transcription is upregulated and initiates from a more upstream site, generating 5'-extended mRNAs. Concomitantly, histones at per1 are deacetylated in a Clr6-dependent manner, suggesting a positive role for Clr6 in transcriptional regulation of per1. Upstream initiation and histone deactylation of per1 are constitutive in cells lacking the serine/threonine kinase oca2, indicating that Oca2 is a repressor of per1. Oca2 interacts with a protein homologous to the Saccharomyces cerevisiae transcriptional activator Cha4 and with Ago1. Loss of Cha4 or Ago1 causes aberrant induction of per1 under noninducing conditions, suggesting that these proteins are also involved in per1 regulation and hence in nitrogen utilization.
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24
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Ruiz-Roig C, Viéitez C, Posas F, de Nadal E. The Rpd3L HDAC complex is essential for the heat stress response in yeast. Mol Microbiol 2010; 76:1049-62. [PMID: 20398213 DOI: 10.1111/j.1365-2958.2010.07167.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To ensure cell survival and growth during temperature increase, eukaryotic organisms respond with transcriptional activation that results in accumulation of proteins that protect against damage and facilitate recovery. To define the global cellular adaptation response to heat stress, we performed a systematic genetic screen that yielded 277 yeast genes required for growth at high temperature. Of these, the Rpd3 histone deacetylase complex was enriched. Global gene expression analysis showed that Rpd3 partially regulated gene expression upon heat shock. The Hsf1 and Msn2/4 transcription factors are the main regulators of gene activation in response to heat stress. RPD3-deficient cells had impaired activation of Msn2/4-dependent genes, while activation of genes controlled by Hsf1 was deacetylase-independent. Rpd3 bound to heat stress-dependent promoters through the Msn2/4 transcription factors, allowing entry of RNA Pol II and activation of transcription upon stress. Finally, we found that the large, but not the small Rpd3 complex regulated cell adaptation in response to heat stress.
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Affiliation(s)
- Clàudia Ruiz-Roig
- Cell Signaling Unit, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
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25
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Multilayered control of gene expression by stress-activated protein kinases. EMBO J 2009; 29:4-13. [PMID: 19942851 DOI: 10.1038/emboj.2009.346] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 11/02/2009] [Indexed: 11/09/2022] Open
Abstract
Stress-activated protein kinases (SAPKs) are key elements for intracellular signalling networks that serve to respond and adapt to extracellular changes. Exposure of yeast to high osmolarity results in the activation of p38-related SAPK, Hog1, which is essential for reprogramming the gene expression capacity of the cell by regulation of several steps of the transcription process. At initiation, active Hog1 not only directly phosphorylates several transcription factors to alter their activities, but also associates at stress-responsive promoters through such transcription factors. Once at the promoters, Hog1 serves as a platform to recruit general transcription factors, chromatin-modifying activities and RNA Pol II. In addition, the SAPK pathway has a role in elongation. At the stress-responsive ORFs, Hog1 recruits the RSC chromatin-remodelling complex to modify nucleosome organization. Several SAPKs from yeast to mammals have maintained some of the regulatory abilities of Hog1. Thus, elucidating the control of gene expression by the Hog1 SAPK should help to understand how eukaryotic cells implement a massive and rapid change on their transcriptional capacity in response to adverse conditions.
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26
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Plakunov VK, Shelemekh OV. Mechanisms of oxygen regulation in microorganisms. Microbiology (Reading) 2009. [DOI: 10.1134/s0026261709050026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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27
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Toggle involving cis-interfering noncoding RNAs controls variegated gene expression in yeast. Proc Natl Acad Sci U S A 2009; 106:18321-6. [PMID: 19805129 DOI: 10.1073/pnas.0909641106] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The identification of specific functional roles for the numerous long noncoding (nc)RNAs found in eukaryotic transcriptomes is currently a matter of intense study amid speculation that these ncRNAs have key regulatory roles. We have identified a pair of cis-interfering ncRNAs in yeast that contribute to the control of variegated gene expression at the FLO11 locus by implementing a regulatory circuit that toggles between two stable states. These capped, polyadenylated ncRNAs are transcribed across the large intergenic region upstream of the FLO11 ORF. As with mammalian long intervening (li)ncRNAs, these yeast ncRNAs (ICR1 and PWR1) are themselves regulated by transcription factors (Sfl1 and Flo8) and chromatin remodelers (Rpd3L) that are key elements in phenotypic transitions in yeast. The mechanism that we describe explains the unanticipated role of a histone deacetylase complex in activating gene expression, because Rpd3L mutants force the ncRNA circuit into a state that silences the expression of the adjacent variegating gene.
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28
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Kremer SB, Gross DS. SAGA and Rpd3 chromatin modification complexes dynamically regulate heat shock gene structure and expression. J Biol Chem 2009; 284:32914-31. [PMID: 19759026 DOI: 10.1074/jbc.m109.058610] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The chromatin structure of heat shock protein (HSP)-encoding genes undergoes dramatic alterations upon transcriptional induction, including, in extreme cases, domain-wide nucleosome disassembly. Here, we use a combination of gene knock-out, in situ mutagenesis, chromatin immunoprecipitation, and expression assays to investigate the role of histone modification complexes in regulating heat shock gene structure and expression in Saccharomyces cerevisiae. Two histone acetyltransferases, Gcn5 and Esa1, were found to stimulate HSP gene transcription. A detailed chromatin immunoprecipitation analysis of the Gcn5-containing SAGA complex (signified by Spt3) revealed its presence within the promoter of every heat shock factor 1-regulated gene examined. The occupancy of SAGA increased substantially upon heat shock, peaking at several HSP promoters within 30-45 s of temperature upshift. SAGA was also efficiently recruited to the coding regions of certain HSP genes (where its presence mirrored that of pol II), although not at others. Robust and rapid recruitment of repressive, Rpd3-containing histone deacetylase complexes was also seen and at all HSP genes examined. A detailed analysis of HSP82 revealed that both Rpd3(L) and Rpd3(S) complexes (signified by Sap30 and Rco1, respectively) were recruited to the gene promoter, yet only Rpd3(S) was recruited to its open reading frame. A consensus URS1 cis-element facilitated the recruitment of each Rpd3 complex to the HSP82 promoter, and this correlated with targeted deacetylation of promoter nucleosomes. Collectively, our observations reveal that SAGA and Rpd3 complexes are rapidly and synchronously recruited to heat shock factor 1-activated genes and suggest that their opposing activities modulate heat shock gene chromatin structure and fine-tune transcriptional output.
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Affiliation(s)
- Selena B Kremer
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA
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29
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Collaboration between the essential Esa1 acetyltransferase and the Rpd3 deacetylase is mediated by H4K12 histone acetylation in Saccharomyces cerevisiae. Genetics 2009; 183:149-60. [PMID: 19596907 DOI: 10.1534/genetics.109.103846] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Histone modifications that regulate chromatin-dependent processes are catalyzed by multisubunit complexes. These can function in both targeting activities to specific genes and in regulating genomewide levels of modifications. In Saccharomyces cerevisiae, Esa1 and Rpd3 have opposing enzymatic activities and are catalytic subunits of multiple chromatin modifying complexes with key roles in processes such as transcriptional regulation and DNA repair. Esa1 is an essential histone acetyltransferase that belongs to the highly conserved MYST family. This study presents evidence that the yeast histone deacetylase gene, RPD3, when deleted, suppressed esa1 conditional mutant phenotypes. Deletion of RPD3 reversed rDNA and telomeric silencing defects and restored global H4 acetylation levels, in addition to rescuing the growth defect of a temperature-sensitive esa1 mutant. This functional genetic interaction between ESA1 and RPD3 was mediated through the Rpd3L complex. The suppression of esa1's growth defect by disruption of Rpd3L was dependent on lysine 12 of histone H4. We propose a model whereby Esa1 and Rpd3L act coordinately to control the acetylation of H4 lysine 12 to regulate transcription, thereby emphasizing the importance of dynamic acetylation and deacetylation of this particular histone residue in maintaining cell viability.
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Alejandro-Osorio AL, Huebert DJ, Porcaro DT, Sonntag ME, Nillasithanukroh S, Will JL, Gasch AP. The histone deacetylase Rpd3p is required for transient changes in genomic expression in response to stress. Genome Biol 2009; 10:R57. [PMID: 19470158 PMCID: PMC2718523 DOI: 10.1186/gb-2009-10-5-r57] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/13/2009] [Accepted: 05/26/2009] [Indexed: 12/20/2022] Open
Abstract
Chromatin-immunoprecipitation and computational analysis implicate Rpd3p as an important co-factor in the network of genes regulating the yeast environmental stress response. Background Yeast responding to stress activate a large gene expression program called the Environmental Stress Response that consists of approximately 600 repressed genes and approximately 300 induced genes. Numerous factors are implicated in regulating subsets of Environmental Stress Response genes; however, a complete picture of Environmental Stress Response regulation remains unclear. We investigated the role of the histone deacetylase Rpd3p, previously linked to the upstream regions of many Environmental Stress Response genes, in producing Environmental Stress Response gene expression changes in response to stress. Results We found that the Rpd3-Large complex is required for proper expression of both induced and repressed Environmental Stress Response genes under multiple stress conditions. Cells lacking RPD3 or the Rpd3-Large subunit PHO23 had a major defect in Environmental Stress Response initiation, particularly during the transient phase of expression immediately after stress exposure. Chromatin-immunoprecipitation showed a direct role for Rpd3-Large at representative genes; however, there were different effects on nucleosome occupancy and histone deacetylation at different promoters. Computational analysis implicated regulators that may act with Rpd3p at Environmental Stress Response genes. We provide genetic and biochemical evidence that Rpd3p is required for binding and action of the stress-activated transcription factor Msn2p, although the contribution of these factors differs for different genes. Conclusions Our results implicate Rpd3p as an important co-factor in the Environmental Stress Response regulatory network, and suggest the importance of histone modification in producing transient changes in gene expression triggered by stress.
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Affiliation(s)
- Adriana L Alejandro-Osorio
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, University Avenue, Madison, WI 53706, USA.
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Zhou J, Zhou BO, Lenzmeier BA, Zhou JQ. Histone deacetylase Rpd3 antagonizes Sir2-dependent silent chromatin propagation. Nucleic Acids Res 2009; 37:3699-713. [PMID: 19372273 PMCID: PMC2699518 DOI: 10.1093/nar/gkp233] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the eukaryotic genome, transcriptionally silent chromatin tends to propagate along a chromosome and encroach upon adjacent active chromatin. The silencing machinery can be stopped by chromatin boundary elements. We performed a screen in Saccharomyces cerevisiae for proteins that may contribute to the establishment of a chromatin boundary. We found that disruption of histone deacetylase Rpd3p results in defective boundary activity, leading to a Sir-dependent local propagation of transcriptional repression. In rpd3 Delta cells, the amount of Sir2p that was normally found in the nucleolus decreased and the amount of Sir2p found at telomeres and at HM and its adjacent loci increased, leading to an extension of silent chromatin in those areas. In addition, Rpd3p interacted directly with chromatin at boundary regions to deacetylate histone H4 at lysine 5 and at lysine 12. Either the mutation of histone H4 at lysine 5 or a decrease in the histone acetyltransferase (HAT) activity of Esa1p abrogated the silencing phenotype associated with rpd3 mutation, suggesting a novel role for the H4 amino terminus in Rpd3p-mediated heterochromatin boundary regulation. Together, these data provide insight into the molecular mechanisms for the anti-silencing functions of Rpd3p during the formation of heterochromatin boundaries.
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Affiliation(s)
- Jing Zhou
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Institutes for Biological Sciences, Chinese Academy of Sciences, The Graduate School, Shanghai 200031, China
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Proteome analysis of aerobically and anaerobically grown Saccharomyces cerevisiae cells. J Proteomics 2008; 71:662-9. [PMID: 19070690 DOI: 10.1016/j.jprot.2008.11.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/12/2008] [Accepted: 11/12/2008] [Indexed: 11/23/2022]
Abstract
The yeast Saccharomyces cerevisiae is able to grow under aerobic as well as anaerobic conditions. We and others previously found that transcription levels of approximately 500 genes differed more than two-fold when cells from anaerobic and aerobic conditions were compared. Here, we addressed the effect of anaerobic growth at the post-transcriptional level by comparing the proteomes of cells isolated from steady-state glucose-limited anaerobic and aerobic cultures. Following two-dimensional gel electrophoresis and mass spectrometry we identified 110 protein spots, corresponding to 75 unique proteins, of which the levels differed more than two-fold between aerobically and anaerobically-grown cells. For 21 of the 110 spots, the intensities decreased more than two-fold whereas the corresponding mRNA levels increased or did not change significantly under anaerobic conditions. The intensities of the other 89 spots changed in the same direction as the mRNA levels of the corresponding genes, although to different extents. For some genes of glycolysis a small increase in mRNA levels, 1.5-2 fold, corresponded to a 5-10 fold increase in protein levels. Extrapolation of our results suggests that transcriptional regulation is the major but not exclusive mechanism for adaptation of S. cerevisiae to anaerobic growth conditions.
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Kundaje A, Xin X, Lan C, Lianoglou S, Zhou M, Zhang L, Leslie C. A predictive model of the oxygen and heme regulatory network in yeast. PLoS Comput Biol 2008; 4:e1000224. [PMID: 19008939 PMCID: PMC2573020 DOI: 10.1371/journal.pcbi.1000224] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 10/08/2008] [Indexed: 11/18/2022] Open
Abstract
Deciphering gene regulatory mechanisms through the analysis of high-throughput expression data is a challenging computational problem. Previous computational studies have used large expression datasets in order to resolve fine patterns of coexpression, producing clusters or modules of potentially coregulated genes. These methods typically examine promoter sequence information, such as DNA motifs or transcription factor occupancy data, in a separate step after clustering. We needed an alternative and more integrative approach to study the oxygen regulatory network in Saccharomyces cerevisiae using a small dataset of perturbation experiments. Mechanisms of oxygen sensing and regulation underlie many physiological and pathological processes, and only a handful of oxygen regulators have been identified in previous studies. We used a new machine learning algorithm called MEDUSA to uncover detailed information about the oxygen regulatory network using genome-wide expression changes in response to perturbations in the levels of oxygen, heme, Hap1, and Co2+. MEDUSA integrates mRNA expression, promoter sequence, and ChIP-chip occupancy data to learn a model that accurately predicts the differential expression of target genes in held-out data. We used a novel margin-based score to extract significant condition-specific regulators and assemble a global map of the oxygen sensing and regulatory network. This network includes both known oxygen and heme regulators, such as Hap1, Mga2, Hap4, and Upc2, as well as many new candidate regulators. MEDUSA also identified many DNA motifs that are consistent with previous experimentally identified transcription factor binding sites. Because MEDUSA's regulatory program associates regulators to target genes through their promoter sequences, we directly tested the predicted regulators for OLE1, a gene specifically induced under hypoxia, by experimental analysis of the activity of its promoter. In each case, deletion of the candidate regulator resulted in the predicted effect on promoter activity, confirming that several novel regulators identified by MEDUSA are indeed involved in oxygen regulation. MEDUSA can reveal important information from a small dataset and generate testable hypotheses for further experimental analysis. Supplemental data are included. The cell uses complex regulatory networks to modulate the expression of genes in response to changes in cellular and environmental conditions. The transcript level of a gene is directly affected by the binding of transcriptional regulators to DNA motifs in its promoter sequence. Therefore, both expression levels of transcription factors and other regulatory proteins as well as sequence information in the promoters contribute to transcriptional gene regulation. In this study, we describe a new computational strategy for learning gene regulatory programs from gene expression data based on the MEDUSA algorithm. We learn a model that predicts differential expression of target genes from the expression levels of regulators, the presence of DNA motifs in promoter sequences, and binding data for transcription factors. Unlike many previous approaches, we do not assume that genes are regulated in clusters, and we learn DNA motifs de novo from promoter sequences as an integrated part of our algorithm. We use MEDUSA to produce a global map of the yeast oxygen and heme regulatory network. To demonstrate that MEDUSA can reveal detailed information about regulatory mechanisms, we perform biochemical experiments to confirm the predicted regulators for an important hypoxia gene.
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Affiliation(s)
- Anshul Kundaje
- Department of Computer Science, Columbia University, New York, New York, United States of America
| | - Xiantong Xin
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Changgui Lan
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Steve Lianoglou
- Department of Physiology, Biophysics, and Systems Biology, Weill Medical College of Cornell University, New York, New York, United States of America
- Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Mei Zhou
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas, United States of America
| | - Li Zhang
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas, United States of America
- * E-mail: (LZ); (CL)
| | - Christina Leslie
- Computational Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- * E-mail: (LZ); (CL)
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Levdansky E, Sharon H, Osherov N. Coding fungal tandem repeats as generators of fungal diversity. FUNGAL BIOL REV 2008. [DOI: 10.1016/j.fbr.2008.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Abstract
In eukaryotes, transcription factors, including both gene-specific activators and general transcription factors (GTFs), operate in a chromatin milieu. Here, we review evidence from gene-specific and genome-wide studies indicating that chromatin presents an environment that is typically permissive for activator binding, conditional for pre-initiation complex (PIC) formation, and inhibitory for productive PIC assembly within coding sequences. We also discuss the role of nucleosome dynamics in facilitating access to transcription factors (TFs) in vivo and indicate some of the principal questions raised by recent findings.
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Affiliation(s)
- Randall H Morse
- Wadsworth Center, New York State Department of Health, Albany, New York 12201-2002, USA.
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Borecka-Melkusova S, Kozovska Z, Hikkel I, Dzugasova V, Subik J. RPD3 and ROM2 are required for multidrug resistance in Saccharomyces cerevisiae. FEMS Yeast Res 2008; 8:414-24. [DOI: 10.1111/j.1567-1364.2007.00352.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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He Q, Battistella L, Morse RH. Mediator requirement downstream of chromatin remodeling during transcriptional activation of CHA1 in yeast. J Biol Chem 2007; 283:5276-86. [PMID: 18093974 DOI: 10.1074/jbc.m708266200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mediator complex is essential for transcription by RNA polymerase II in eukaryotes. Although chromatin remodeling is an integral part of transcriptional activation at many promoters, whether Mediator is required for this function has not been determined. Here we have used the yeast CHA1 gene to study the role of Mediator in chromatin remodeling and recruitment of the transcription machinery. We show by chromatin immunoprecipitation that Mediator subunits are recruited to the induced CHA1 promoter. Inactivation of Mediator at 37 degrees C in yeast harboring the srb4-138 (med17) ts mutation severely reduces CHA1 activation and prevents recruitment to the induced CHA1 promoter of Med18/Srb5, from the head module of Mediator, and Med14/Rgr1, which bridges the middle and tail modules. In contrast, recruitment of Med15/Gal11 from the tail module is unaffected in med17 ts yeast at 37 degrees C. Recruitment of TATA-binding protein (TBP) is severely compromised in the absence of functional Mediator, whereas Kin28 and polymerase II recruitment are reduced but to a lesser extent. Induced levels of histone H3K4me3 at the CHA1 promoter are not diminished by inactivation of Mediator, whereas recruitment of Paf1 and of Ser2- and Ser5-phosphorylated forms of Rbp1 are reduced but not eliminated. Loss of histone H3 from the induced CHA1 promoter is seen in wild type yeast but is greatly reduced by loss of intact Mediator. In contrast, Swi/Snf recruitment and nucleosome remodeling are unaffected by loss of Mediator function. Thus, Mediator is required for recruitment of the transcription machinery subsequent to chromatin remodeling during CHA1 induction.
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Affiliation(s)
- Qiye He
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, New York 12201-2002, USA
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38
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Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Xin X, Lan C, Lee HC, Zhang L. Regulation of the HAP1 gene involves positive actions of histone deacetylases. Biochem Biophys Res Commun 2007; 362:120-125. [PMID: 17706600 PMCID: PMC2030606 DOI: 10.1016/j.bbrc.2007.07.156] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 07/30/2007] [Indexed: 10/23/2022]
Abstract
The yeast transcriptional regulator Hap1 promotes both transcriptional activation and repression. Previous studies have shown that Hap1 binds to the promoter of its own gene and represses its transcription. In this report, we identified the DNA site that allows Hap1-binding with high affinity. This Hap1-binding site contains only one CGG triplet and is distinct from the typical Hap1-binding upstream activation sequences (UASs) mediating transcriptional activation. Furthermore, at the HAP1 promoter, Ssa is bound to DNA with Hap1, whereas Hsp90 is not bound. Intriguingly, we found that histone deacetylases, including Rpd3, Hda1, Sin3 and Hos1, are not required for the repression of the HAP1 gene by Hap1. Rather, they are required for transcriptional activation of the HAP1 promoter, and this requirement is dependent on the HAP1 basal promoter. These results reveal a complex mechanism of transcriptional regulation at the HAP1 promoter, involving multiple DNA elements and regulatory proteins.
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Affiliation(s)
- Xiantong Xin
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 60 Haven Avenue, B-106, New York, NY 10032, USA
| | - Changgui Lan
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 60 Haven Avenue, B-106, New York, NY 10032, USA
| | - Hee Chul Lee
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 60 Haven Avenue, B-106, New York, NY 10032, USA
| | - Li Zhang
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 60 Haven Avenue, B-106, New York, NY 10032, USA.
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