1
|
Brault A, Mbuya B, Labbé S. Sib1, Sib2, and Sib3 proteins are required for ferrichrome-mediated cross-feeding interaction between Schizosaccharomyces pombe and Saccharomyces cerevisiae. Front Microbiol 2022; 13:962853. [PMID: 35928155 PMCID: PMC9344042 DOI: 10.3389/fmicb.2022.962853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/01/2022] [Indexed: 11/15/2022] Open
Abstract
Although Saccharomyces cerevisiae is unable to produce siderophores, this fungal organism can assimilate iron bound to the hydroxamate-type siderophore ferrichrome (Fc) produced and secreted by other microbes. Fc can enter S. cerevisiae cells via Arn1. Unlike S. cerevisiae, Schizosaccharomyces pombe synthesizes and secretes Fc. The sib1+ and sib2+ genes encode, respectively, a Fc synthetase and an ornithine-N5-oxygenase, which are required for Fc production. When both genes were expressed in S. pombe, cross-feeding experiments revealed that S. cerevisiae fet3Δ arn1-4Δ cells expressing Arn1 could grow in the vicinity of S. pombe under low-iron conditions. In contrast, deletion of sib1+ and sib2+ produced a defect in the ability of S. pombe to keep S. cerevisiae cells alive when Fc is used as the sole source of iron. Further analysis identified a gene designated sib3+ that encodes an N5-transacetylase required for Fc production in S. pombe. The sib3Δ mutant strain exhibited a severe growth defect in iron-poor media, and it was unable to promote Fc-dependent growth of S. cerevisiae cells. Microscopic analyses of S. pombe cells expressing a functional Sib3-GFP protein revealed that Sib3 was localized throughout the cells, with a proportion of Sib3 being colocalized with Sib1 and Sib2 within the cytosol. Collectively, these results describe the first example of a one-way cross-feeding interaction, with S. pombe providing Fc that enables S. cerevisiae to grow when Fc is used as the sole source of iron.
Collapse
|
2
|
Kim S, Park J, Kim D, Choi S, Moon H, Young Shin J, Kim J, Son H. Development of a versatile copper-responsive gene expression system in the plant-pathogenic fungus Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2021; 22:1427-1435. [PMID: 34390122 PMCID: PMC8518565 DOI: 10.1111/mpp.13118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/16/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Fusarium graminearum is an important plant-pathogenic fungus that causes Fusarium head blight on wheat and barley, and ear rot on maize worldwide. This fungus has been widely used as a model organism to study various biological processes of plant-pathogenic fungi because of its amenability to genetic manipulation and well-established outcross system. Gene deletion and overexpression/constitutive expression of target genes are tools widely used to investigate the molecular mechanism underlying fungal development, virulence, and secondary metabolite production. However, for fine-tuning gene expression and studying essential genes, a conditional gene expression system is necessary that enables repression or induction of gene expression by modifying external conditions. Until now, only a few conditional expression systems have been developed in plant-pathogenic fungi. This study proposes a new and versatile conditional gene expression system in F. graminearum using the promoter of a copper-responsive gene, designated F. graminearum copper-responsive 1 (FCR1). Transcript levels of FCR1 were found to be greatly affected by copper availability conditions. Moreover, the promoter (PFCR1 ), 1 kb upstream of the FCR1 open reading frame, was sufficient to confer copper-dependent gene expression. Replacement of a green fluorescent protein gene and FgENA5 promoter with a PFCR1 promoter clearly showed that PFCR1 could be used for fine-tuning gene expression in this fungus. We also demonstrated the applicability of this conditional gene expression system to an essential gene study by replacing the promoter of FgIRE1, an essential gene of F. graminearum. This enabled the generation of FgIRE1 suppression mutants, which allowed functional characterization of the gene. This study reported the first conditional gene expression system in F. graminearum using both repression and induction. This system would be a convenient way to precisely control gene expression and will be used to determine the biological functions of various genes, including essential ones.
Collapse
Affiliation(s)
- Sieun Kim
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
| | - Jiyeun Park
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
| | - Dohun Kim
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
| | - Soyoung Choi
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
| | - Heeji Moon
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
| | - Ji Young Shin
- Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
| | - Jung‐Eun Kim
- Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
| | - Hokyoung Son
- Department of Agricultural BiotechnologySeoul National UniversitySeoulRepublic of Korea
- Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoulRepublic of Korea
| |
Collapse
|
3
|
Copper overload in Paracoccidioides lutzii results in the accumulation of ergosterol and melanin. Microbiol Res 2020; 239:126524. [PMID: 32570056 DOI: 10.1016/j.micres.2020.126524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/14/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023]
Abstract
Paracoccidioidomycosis is a highly prevalent systemic mycosis in Latin America, caused by fungi of the genus Paracoccidioides. Copper is essential for eukaryotes and bacteria. This micronutrient is used in many vital biochemical processes, although metal excess levels can be toxic for organisms. Pathways underlying copper overload are poorly understood in members of the Paracoccidioides complex. The responses of Paracoccidioides lutzii yeast cells to copper overload were here evaluated. The results showed that under copper overload, cells presented a dark brown pigment, identified as melanin. Proteomic analyses identified mainly the accumulation of proteins related to amino acids metabolism, ergosterol synthesis and melanin production, suggesting that P. lutzii responds to copper overload by changing aspects of its metabolism and also plasma membrane and cell wall remodeling. Proteomic data were confirmed by biochemical analysis.
Collapse
|
4
|
The Role of Copper Homeostasis at the Host-Pathogen Axis: From Bacteria to Fungi. Int J Mol Sci 2019; 20:ijms20010175. [PMID: 30621285 PMCID: PMC6337107 DOI: 10.3390/ijms20010175] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/28/2018] [Accepted: 12/29/2018] [Indexed: 02/01/2023] Open
Abstract
Copper is an essential trace element participating in many vital biological processes, however it becomes a toxic agent when in excess. Thus, precise and tight regulation of copper homeostasis processes, including transport, delivery, storage, detoxification, and efflux machineries, is important, ensuring that only the amount needed to sustain basic biological functions and simultaneously prevent copper toxicity in the cell is maintained. Numerous exciting studies have revealed that copper plays an indispensable role at the microbial pathogen-host axis for entities ranging from pathogenic bacteria to deadly fungal species. Analyses of copper homeostases in bacteria and fungi extensively demonstrate that copper is utilized by the host immune system as an anti-microbial agent. The expression of copper efflux and detoxification from microbial pathogens is induced to counteract the host's copper bombardment, which in turn disrupts these machineries, resulting in the attenuation of microbial survival in host tissue. We hereby review the latest work in copper homeostases in pathogenic bacteria and fungi and focus on the maintenance of a copper balance at the pathogen-host interaction axis.
Collapse
|
5
|
Beaudoin J, Ioannoni R, Normant V, Labbé S. A role for the transcription factor Mca1 in activating the meiosis-specific copper transporter Mfc1. PLoS One 2018; 13:e0201861. [PMID: 30086160 PMCID: PMC6080790 DOI: 10.1371/journal.pone.0201861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/23/2018] [Indexed: 12/19/2022] Open
Abstract
When reproduction in fungi takes place by sexual means, meiosis enables the formation of haploid spores from diploid precursor cells. Copper is required for completion of meiosis in Schizosaccharomyces pombe. During the meiotic program, genes encoding copper transporters exhibit distinct temporal expression profiles. In the case of the major facilitator copper transporter 1 (Mfc1), its maximal expression is induced during middle-phase meiosis and requires the presence of the Zn6Cys2 binuclear cluster-type transcription factor Mca1. In this study, we further characterize the mechanism by which Mca1 affects the copper-starvation-induced expression of mfc1+. Using a chromatin immunoprecipitation (ChIP) approach, results showed that a functional Mca1-TAP occupies the mfc1+ promoter irrespective of whether this gene is transcriptionally active. Under conditions of copper starvation, results showed that the presence of Mca1 promotes RNA polymerase II (Pol II) occupancy along the mfc1+ transcribed region. In contrast, Pol II did not significantly occupy the mfc1+ locus in meiotic cells that were incubated in the presence of copper. Further analysis by ChIP assays revealed that binding of Pol II to chromatin at the chromosomal locus of mfc1+ is exclusively detected during meiosis and absent in cells proliferating in mitosis. Protein function analysis of a series of internal mutants compared to the full-length Mca1 identified a minimal form of Mca1 consisting of its DNA-binding domain (residues 1 to 150) fused to the amino acids 299 to 600. This shorter form is sufficient to enhance Pol II occupancy at the mfc1+ locus under low copper conditions. Taken together, these results revealed novel characteristics of Mca1 and identified an internal region of Mca1 that is required to promote Pol II-dependent mfc1+ transcription during meiosis.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Raphaël Ioannoni
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Vincent Normant
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Simon Labbé
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
- * E-mail:
| |
Collapse
|
6
|
Cai Z, Du W, Zhang Z, Guan L, Zeng Q, Chai Y, Dai C, Lu L. TheAspergillus fumigatustranscription factor AceA is involved not only in Cu but also in Zn detoxification through regulating transporters CrpA and ZrcA. Cell Microbiol 2018; 20:e12864. [DOI: 10.1111/cmi.12864] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/03/2018] [Accepted: 05/08/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Zhendong Cai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Wenlong Du
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Zheng Zhang
- Department of Dermatology, Jinling Hospital, School of Medicine; Nanjing University; Nanjing China
| | - Luyu Guan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Qiuqiong Zeng
- Department of Dermatology, Jinling Hospital, School of Medicine; Nanjing University; Nanjing China
| | - Yanfei Chai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Chuanchao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| |
Collapse
|
7
|
Garcia Silva-Bailão M, Lobato Potenciano da Silva K, Raniere Borges dos Anjos L, de Sousa Lima P, de Melo Teixeira M, Maria de Almeida Soares C, Melo Bailão A. Mechanisms of copper and zinc homeostasis in pathogenic black fungi. Fungal Biol 2018; 122:526-537. [DOI: 10.1016/j.funbio.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 02/08/2023]
|
8
|
Abstract
Fungal cells colonize and proliferate in distinct niches, from soil and plants to diverse tissues in human hosts. Consequently, fungi are challenged with the goal of obtaining nutrients while simultaneously elaborating robust regulatory mechanisms to cope with a range of availability of nutrients, from scarcity to excess. Copper is essential for life but also potentially toxic. In this review we describe the sophisticated homeostatic mechanisms by which fungi acquire, utilize, and control this biochemically versatile trace element. Fungal pathogens, which can occupy distinct host tissues that have their own intrinsic requirements for copper homeostasis, have evolved mechanisms to acquire copper to successfully colonize the host, disseminate to other tissues, and combat host copper bombardment mechanisms that would otherwise mitigate virulence.
Collapse
Affiliation(s)
| | | | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology.,Department of Molecular Genetics and Microbiology, and.,Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710;
| |
Collapse
|
9
|
Plante S, Normant V, Ramos-Torres KM, Labbé S. Cell-surface copper transporters and superoxide dismutase 1 are essential for outgrowth during fungal spore germination. J Biol Chem 2017; 292:11896-11914. [PMID: 28572514 PMCID: PMC5512082 DOI: 10.1074/jbc.m117.794677] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/26/2017] [Indexed: 11/06/2022] Open
Abstract
During fungal spore germination, a resting spore returns to a conventional mode of cell division and resumes vegetative growth, but the requirements for spore germination are incompletely understood. Here, we show that copper is essential for spore germination in Schizosaccharomyces pombe Germinating spores develop a single germ tube that emerges from the outer spore wall in a process called outgrowth. Under low-copper conditions, the copper transporters Ctr4 and Ctr5 are maximally expressed at the onset of outgrowth. In the case of Ctr6, its expression is broader, taking place before and during outgrowth. Spores lacking Ctr4, Ctr5, and the copper sensor Cuf1 exhibit complete germination arrest at outgrowth. In contrast, ctr6 deletion only partially interferes with formation of outgrowing spores. At outgrowth, Ctr4-GFP and Ctr5-Cherry first co-localize at the spore contour, followed by re-location to a middle peripheral spore region. Subsequently, they move away from the spore body to occupy the periphery of the nascent cell. After breaking of spore dormancy, Ctr6 localizes to the vacuole membranes that are enriched in the spore body relative to the germ tube. Using a copper-binding tracker, results showed that labile copper is preferentially localized to the spore body. Further analysis showed that Ctr4 and Ctr6 are required for copper-dependent activation of the superoxide dismutase 1 (SOD1) during spore germination. This activation is critical because the loss of SOD1 activity blocked spore germination at outgrowth. Taken together, these results indicate that cell-surface copper transporters and SOD1 are required for completion of the spore germination program.
Collapse
MESH Headings
- Cation Transport Proteins/genetics
- Cation Transport Proteins/metabolism
- Copper/metabolism
- Enzyme Activation
- Gene Deletion
- Gene Expression Regulation, Fungal
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Microscopy, Fluorescence
- Microscopy, Interference
- Microscopy, Phase-Contrast
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Transport
- RNA, Fungal/metabolism
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- SLC31 Proteins
- Schizosaccharomyces/cytology
- Schizosaccharomyces/growth & development
- Schizosaccharomyces/metabolism
- Schizosaccharomyces/physiology
- Schizosaccharomyces pombe Proteins/genetics
- Schizosaccharomyces pombe Proteins/metabolism
- Spores, Fungal/cytology
- Spores, Fungal/growth & development
- Spores, Fungal/metabolism
- Spores, Fungal/physiology
- Superoxide Dismutase-1/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Red Fluorescent Protein
Collapse
Affiliation(s)
- Samuel Plante
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Vincent Normant
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Karla M Ramos-Torres
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720
| | - Simon Labbé
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada.
| |
Collapse
|
10
|
The roles of zinc and copper sensing in fungal pathogenesis. Curr Opin Microbiol 2016; 32:128-134. [PMID: 27327380 PMCID: PMC4992176 DOI: 10.1016/j.mib.2016.05.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/13/2016] [Accepted: 05/19/2016] [Indexed: 12/17/2022]
Abstract
Zinc and copper are essential trace elements required for cell function. Nutrient Immunity restricts zinc and copper access and mediates toxicity. Divergent fungi integrate zinc and copper responsive regulons for pathogenesis.
All organisms must secure essential trace nutrients, including iron, zinc, manganese and copper for survival and proliferation. However, these very nutrients are also highly toxic if present at elevated levels. Mammalian immunity has harnessed both the essentiality and toxicity of micronutrients to defend against microbial invasion — processes known collectively as ‘nutritional immunity’. Therefore, pathogenic microbes must possess highly effective micronutrient assimilation and detoxification mechanisms to survive and proliferate within the infected host. In this review we compare and contrast the micronutrient homeostatic mechanisms of Cryptococcus and Candida — yeasts which, despite ancient evolutionary divergence, account for over a million life-threatening infections per year. We focus on two emerging arenas within the host–pathogen battle for essential trace metals: adaptive responses to zinc limitation and copper availability.
Collapse
|
11
|
Normant V, Beaudoin J, Labbé S. An antisense RNA-mediated mechanism eliminates a meiosis-specific copper-regulated transcript in mitotic cells. J Biol Chem 2015; 290:22622-37. [PMID: 26229103 DOI: 10.1074/jbc.m115.674556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Indexed: 11/06/2022] Open
Abstract
Sense and antisense transcripts produced from convergent gene pairs could interfere with the expression of either partner gene. In Schizosaccharomyces pombe, we found that the iss1(+) gene produces two transcript isoforms, including a long antisense mRNA that is complementary to the meiotic cum1(+) sense transcript, inhibiting cum1(+) expression in vegetative cells. Inhibition of cum1(+) transcription was not at the level of its initiation because fusion of the cum1(+) promoter to the lacZ gene showed that activation of the reporter gene occurs in response to low copper conditions. Further analysis showed that the transcription factor Cuf1 and conserved copper-signaling elements (CuSEs) are required for induction of cum1(+)-lacZ transcription under copper deficiency. Insertion of a multipartite polyadenylation signal immediately downstream of iss1(+) led to the exclusive production of a shorter iss1(+) mRNA isoform, thereby allowing accumulation of cum1(+) sense mRNA in copper-limited vegetative cells. This finding suggested that the long iss1(+) antisense mRNA could pair with cum1(+) sense mRNA, thereby producing double-stranded RNA molecules that could induce RNAi. We consistently found that mutant strains for RNAi (dcr1Δ, ago1Δ, rdp1Δ, and clr4Δ) are defective in selectively eliminating cum1(+) sense transcript in the G1 phase of the cell cycle. Taken together, these results describe the first example of a copper-regulated meiotic gene repressed by an antisense transcription mechanism in vegetative cells.
Collapse
Affiliation(s)
- Vincent Normant
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Jude Beaudoin
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | - Simon Labbé
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| |
Collapse
|
12
|
Abstract
The fission yeast Schizosaccharomyces pombe has been successfully used as a model to gain fundamental knowledge in understanding how eukaryotic cells acquire copper during vegetative growth. These studies have revealed the existence of a heteromeric Ctr4-Ctr5 plasma membrane complex that mediates uptake of copper within the cells. Furthermore, additional studies have led to the identification of one of the first vacuolar copper transporters, Ctr6, as well as the copper-responsive Cuf1 transcription factor. Recent investigations have extended the use of S. pombe to elucidate new roles for copper metabolism in meiotic differentiation. For example, these studies have led to the discovery of Mfc1, which turned out to be the first example of a meiosis-specific copper transporter. Whereas copper-dependent transcriptional regulation of the Ctr family members is under the control of Cuf1 during mitosis or meiosis, meiosis-specific copper transporter Mfc1 is regulated by the recently discovered transactivator Mca1. It is foreseeable that identification of novel meiotic copper-related proteins will serve as stepping stones to unravel fundamental aspects of copper homoeostasis.
Collapse
|
13
|
Pluskal T, Ueno M, Yanagida M. Genetic and metabolomic dissection of the ergothioneine and selenoneine biosynthetic pathway in the fission yeast, S. pombe, and construction of an overproduction system. PLoS One 2014; 9:e97774. [PMID: 24828577 PMCID: PMC4020840 DOI: 10.1371/journal.pone.0097774] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/24/2014] [Indexed: 12/22/2022] Open
Abstract
Ergothioneine is a small, sulfur-containing metabolite (229 Da) synthesized by various species of bacteria and fungi, which can accumulate to millimolar levels in tissues or cells (e.g. erythrocytes) of higher eukaryotes. It is commonly marketed as a dietary supplement due to its proposed protective and antioxidative functions. In this study we report the genes forming the two-step ergothioneine biosynthetic pathway in the fission yeast, Schizosaccharomyces pombe. We identified the first gene, egt1+ (SPBC1604.01), by sequence homology to previously published genes from Neurospora crassa and Mycobacterium smegmatis. We showed, using metabolomic analysis, that the Δegt1 deletion mutant completely lacked ergothioneine and its precursors (trimethyl histidine/hercynine and hercynylcysteine sulfoxide). Since the second step of ergothioneine biosynthesis has not been characterized in eukaryotes, we examined four putative homologs (Nfs1/SPBC21D10.11c, SPAC11D3.10, SPCC777.03c, and SPBC660.12c) of the corresponding mycobacterial enzyme EgtE. Among deletion mutants of these genes, only one (ΔSPBC660.12c, designated Δegt2) showed a substantial decrease in ergothioneine, accompanied by accumulation of its immediate precursor, hercynylcysteine sulfoxide. Ergothioneine-deficient strains exhibited no phenotypic defects during vegetative growth or quiescence. To effectively study the role of ergothioneine, we constructed an egt1+ overexpression system by replacing its native promoter with the nmt1+ promoter, which is inducible in the absence of thiamine. We employed three versions of the nmt1 promoter with increasing strength of expression and confirmed corresponding accumulations of ergothioneine. We quantified the intracellular concentration of ergothioneine in S. pombe (0.3, 157.4, 41.6, and up to 1606.3 µM in vegetative, nitrogen-starved, glucose-starved, and egt1+-overexpressing cells, respectively) and described its gradual accumulation under long-term quiescence. Finally, we demonstrated that the ergothioneine pathway can also synthesize selenoneine, a selenium-containing derivative of ergothioneine, when the culture medium is supplemented with selenium. We further found that selenoneine biosynthesis involves a novel intermediate compound, hercynylselenocysteine.
Collapse
Affiliation(s)
- Tomáš Pluskal
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashihiroshima-shi, Hiroshima, Japan
| | - Masaru Ueno
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashihiroshima-shi, Hiroshima, Japan
| | - Mitsuhiro Yanagida
- G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, Japan
- * E-mail:
| |
Collapse
|
14
|
Plante S, Ioannoni R, Beaudoin J, Labbé S. Characterization of Schizosaccharomyces pombe copper transporter proteins in meiotic and sporulating cells. J Biol Chem 2014; 289:10168-81. [PMID: 24569997 DOI: 10.1074/jbc.m113.543678] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Meiosis requires copper to undertake its program in which haploid gametes are produced from diploid precursor cells. In Schizosaccharomyces pombe, copper is transported by three members of the copper transporter (Ctr) family, namely Ctr4, Ctr5, and Ctr6. Although central for sexual differentiation, very little is known about the expression profile, cellular localization, and physiological contribution of the Ctr proteins during meiosis. Analysis of gene expression of ctr4(+) and ctr5(+) revealed that they are primarily expressed in early meiosis under low copper conditions. In the case of ctr6(+), its expression is broader, being detected throughout the entire meiotic process with an increase during middle- and late-phase meiosis. Whereas the expression of ctr4(+) and ctr5(+) is exclusively dependent on the presence of Cuf1, ctr6(+) gene expression relies on two distinct regulators, Cuf1 and Mei4. Ctr4 and Ctr5 proteins co-localize at the plasma membrane shortly after meiotic induction, whereas Ctr6 is located on the membrane of vacuoles. After meiotic divisions, Ctr4 and Ctr5 disappear from the cell surface, whereas Ctr6 undergoes an intracellular re-location to co-localize with the forespore membrane. Under copper-limiting conditions, disruption of ctr4(+) and ctr6(+) results in altered SOD1 activity, whereas these mutant cells exhibit substantially decreased levels of CAO activity mostly in early- and middle-phase meiosis. Collectively, these results emphasize the notion that Ctr proteins exhibit differential expression, localization, and contribution in delivering copper to SOD1 and Cao1 proteins during meiosis.
Collapse
Affiliation(s)
- Samuel Plante
- From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada
| | | | | | | |
Collapse
|
15
|
Systematic genetic analysis of transcription factors to map the fission yeast transcription-regulatory network. Biochem Soc Trans 2013; 41:1696-700. [DOI: 10.1042/bst20130224] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mapping transcriptional-regulatory networks requires the identification of target genes, binding specificities and signalling pathways of transcription factors. However, the characterization of each transcription factor sufficiently for deciphering such networks remains laborious. The recent availability of overexpression and deletion strains for almost all of the transcription factor genes in the fission yeast Schizosaccharomyces pombe provides a valuable resource to better investigate transcription factors using systematic genetics. In the present paper, I review and discuss the utility of these strain collections combined with transcriptome profiling and genome-wide chromatin immunoprecipitation to identify the target genes of transcription factors.
Collapse
|
16
|
Kamaladini H, Nor Akmar Abdullah S, Aziz MA, Ismail IB, Haddadi F. Breaking-off tissue specific activity of the oil palm metallothionein-like gene promoter in T(1) seedlings of tomato exposed to metal ions. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:346-354. [PMID: 23290536 DOI: 10.1016/j.jplph.2012.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/12/2012] [Accepted: 10/13/2012] [Indexed: 06/01/2023]
Abstract
Metallothioneins (MTs) are cysteine-rich metal-binding proteins that are involved in cell growth regulation, transportation of metal ions and detoxification of heavy metals. A mesocarp-specific metallothionein-like gene (MT3-A) promoter was isolated from the oil palm (Elaeis guineensis Jacq). A vector construct containing the MT3-A promoter fused to the β-glucuronidase (GUS) gene in the pCAMBIA 1304 vector was produced and used in Agrobacterium-mediated transformation of tomato. Histochemical GUS assay of different tissues of transgenic tomato showed that the MT3-A promoter only drove GUS expression in the reproductive tissues and organs, including the anther, fruit and seed coat. Competitive RT-PCR and GUS fluorometric assay showed changes in the level of GUS mRNA and enzyme activity in the transgenic tomato (T(0)). No GUS mRNA was found in roots and leaves of transgenic tomato. In contrast, the leaves of transgenic tomato seedlings (T(1)) produced the highest GUS activity when treated with 150 μM Cu(2+) compared to the control (without Cu(2+)). However, Zn(2+) and Fe(2+) treatments did not show GUS expression in the leaves of the transgenic tomato seedlings. Interestingly, the results showed a breaking-off tissue-specific activity of the oil palm MT3-A promoter in T(1) seedlings of tomato when subjected to Cu(2+) ions.
Collapse
Affiliation(s)
- Hossein Kamaladini
- Department of Agriculture Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | | | | | | | | |
Collapse
|
17
|
Transcriptional regulation of the copper transporter mfc1 in meiotic cells. EUKARYOTIC CELL 2013; 12:575-90. [PMID: 23397571 DOI: 10.1128/ec.00019-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mfc1 is a meiosis-specific protein that mediates copper transport during the meiotic program in Schizosaccharomyces pombe. Although the mfc1(+) gene is induced at the transcriptional level in response to copper deprivation, the molecular determinants that are required for its copper starvation-dependent induction are unknown. Promoter deletion and site-directed mutagenesis have allowed identification of a new cis-regulatory element in the promoter region of the mfc1(+) gene. This cis-acting regulatory sequence containing the sequence TCGGCG is responsible for transcriptional activation of mfc1(+) under low-copper conditions. The TCGGCG sequence contains a CGG triplet known to serve as a binding site for members of the Zn(2)Cys(6) binuclear cluster transcriptional regulator family. In agreement with this fact, one member of this group of regulators, denoted Mca1, was found to be required for maximum induction of mfc1(+) gene expression. Analysis of Mca1 cellular distribution during meiosis revealed that it colocalizes with both chromosomes and sister chromatids during early, middle, and late phases of the meiotic program. Cells lacking Mca1 exhibited a meiotic arrest at metaphase I under low-copper conditions. Binding studies revealed that the N-terminal 150-residue segment of Mca1 expressed as a fusion protein in Escherichia coli specifically interacts with the TCGGCG sequence of the mfc1(+) promoter. Taken together, these results identify the cis-regulatory TCGGCG sequence and the transcription factor Mca1 as critical components for activation of the meiotic copper transport mfc1(+) gene in response to copper starvation.
Collapse
|
18
|
Tmac1, a transcription factor which regulated high affinity copper transport in Trichoderma reesei. Microbiol Res 2012; 167:536-43. [DOI: 10.1016/j.micres.2012.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 02/06/2012] [Accepted: 02/10/2012] [Indexed: 11/18/2022]
|
19
|
Cuf2 is a novel meiosis-specific regulatory factor of meiosis maturation. PLoS One 2012; 7:e36338. [PMID: 22558440 PMCID: PMC3338643 DOI: 10.1371/journal.pone.0036338] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/30/2012] [Indexed: 12/03/2022] Open
Abstract
Background Meiosis is the specialized form of the cell cycle by which diploid cells produce the haploid gametes required for sexual reproduction. Initiation and progression through meiosis requires that the expression of the meiotic genes is precisely controlled so as to provide the correct gene products at the correct times. During meiosis, four temporal gene clusters are either induced or repressed by a cascade of transcription factors. Principal Findings In this report a novel copper-fist-type regulator, Cuf2, is shown to be expressed exclusively during meiosis. The expression profile of the cuf2+ mRNA revealed that it was induced during middle-phase meiosis. Both cuf2+ mRNA and protein levels are unregulated by copper addition or starvation. The transcription of cuf2+ required the presence of a functional mei4+ gene encoding a key transcription factor that activates the expression of numerous middle meiotic genes. Microscopic analyses of cells expressing a functional Cuf2-GFP protein revealed that Cuf2 co-localized with both homologous chromosomes and sister chromatids during the meiotic divisions. Cells lacking Cuf2 showed an elevated and sustained expression of several of the middle meiotic genes that persisted even during late meiosis. Moreover, cells carrying disrupted cuf2Δ/cuf2Δ alleles displayed an abnormal morphology of the forespore membranes and a dramatic reduction of spore viability. Significance Collectively, the results revealed that Cuf2 functions in the timely repression of the middle-phase genes during meiotic differentiation.
Collapse
|
20
|
Abstract
Meiosis is a specialized cell division process by which diploid germ line cells generate haploid gametes, which are required for sexual reproduction. During this process, several micronutrients are required, including copper ions. Despite important roles for copper-dependent proteins during meiosis, their mechanisms of action remain poorly understood. In a recently publication, we reported the discovery of Mfc1, the first example ever reported of a meiosis-specific copper transporter. Although Mfc1 did not exhibit any significant amino acid sequence similarities with members of the Ctr family of copper transporters, it harbored putative copper coordination motifs. Microarray data showed that mfc1+ was the most highly induced of all meiotic genes detected under copper-limiting conditions. Analysis of Mfc1 localization during meiosis revealed that it localized at the forespore membrane during middle and late phases of the meiotic program. Interestingly, live-cell copper imaging using a copper-binding tracker revealed accumulation of copper ions into the forespore in wild-type cells. In contrast, mutant cells lacking Mfc1 displayed an intracellular distribution of copper ions that was dispersed throughout the ascospores without any marked preference for the forespore. We propose that Mfc1 is required to mobilize copper into the forespore, thereby providing copper to copper-requiring enzymes of the developing spores.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie; Faculté de Médecine et des Sciences de la Santé; Université de Sherbrooke; Sherbrooke, QC Canada
| | | | | |
Collapse
|
21
|
Nevitt T, Ohrvik H, Thiele DJ. Charting the travels of copper in eukaryotes from yeast to mammals. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1580-93. [PMID: 22387373 DOI: 10.1016/j.bbamcr.2012.02.011] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/08/2012] [Accepted: 02/16/2012] [Indexed: 12/13/2022]
Abstract
Throughout evolution, all organisms have harnessed the redox properties of copper (Cu) and iron (Fe) as a cofactor or structural determinant of proteins that perform critical functions in biology. At its most sobering stance to Earth's biome, Cu biochemistry allows photosynthetic organisms to harness solar energy and convert it into the organic energy that sustains the existence of all nonphotosynthetic life forms. The conversion of organic energy, in the form of nutrients that include carbohydrates, amino acids and fatty acids, is subsequently released during cellular respiration, itself a Cu-dependent process, and stored as ATP that is used to drive a myriad of critical biological processes such as enzyme-catalyzed biosynthetic processes, transport of cargo around cells and across membranes, and protein degradation. The life-supporting properties of Cu incur a significant challenge to cells that must not only exquisitely balance intracellular Cu concentrations, but also chaperone this redox-active metal from its point of cellular entry to its ultimate destination so as to avert the potential for inappropriate biochemical interactions or generation of damaging reactive oxidative species (ROS). In this review we chart the travels of Cu from the extracellular milieu of fungal and mammalian cells, its path within the cytosol as inferred by the proteins and ligands that escort and deliver Cu to intracellular organelles and protein targets, and its journey throughout the body of mammals. This article is part of a Special Issue entitled: Cell Biology of Metals.
Collapse
Affiliation(s)
- Tracy Nevitt
- Department of Pharmacology, Duke University Medical School, Durham, NC 27710, USA
| | | | | |
Collapse
|
22
|
Beaudoin J, Ioannoni R, López-Maury L, Bähler J, Ait-Mohand S, Guérin B, Dodani SC, Chang CJ, Labbé S. Mfc1 is a novel forespore membrane copper transporter in meiotic and sporulating cells. J Biol Chem 2011; 286:34356-72. [PMID: 21828039 DOI: 10.1074/jbc.m111.280396] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To gain insight in the molecular basis of copper homeostasis during meiosis, we have used DNA microarrays to analyze meiotic gene expression in the model yeast Schizosaccharomyces pombe. Profiling data identified a novel meiosis-specific gene, termed mfc1(+), that encodes a putative major facilitator superfamily-type transporter. Although Mfc1 does not exhibit any significant sequence homology with the copper permease Ctr4, it contains four putative copper-binding motifs that are typically found in members of the copper transporter family of copper transporters. Similarly to the ctr4(+) gene, the transcription of mfc1(+) was induced by low concentrations of copper. However, its temporal expression profile during meiosis was distinct to ctr4(+). Whereas Ctr4 was observed at the plasma membrane shortly after induction of meiosis, Mfc1 appeared later in precursor vesicles and, subsequently, at the forespore membrane of ascospores. Using the fluorescent copper-binding tracker Coppersensor-1 (CS1), labile cellular copper was primarily detected in the forespores in an mfc1(+)/mfc1(+) strain, whereas an mfc1Δ/mfc1Δ mutant exhibited an intracellular dispersed punctate distribution of labile copper ions. In addition, the copper amine oxidase Cao1, which localized primarily in the forespores of asci, was fully active in mfc1(+)/mfc1(+) cells, but its activity was drastically reduced in an mfc1Δ/mfc1Δ strain. Furthermore, our data showed that meiotic cells that express the mfc1(+) gene have a distinct developmental advantage over mfc1Δ/mfc1Δ mutant cells when copper is limiting. Taken together, the data reveal that Mfc1 serves to transport copper for accurate and timely meiotic differentiation under copper-limiting conditions.
Collapse
Affiliation(s)
- Jude Beaudoin
- Départements de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Ding C, Yin J, Tovar EMM, Fitzpatrick DA, Higgins DG, Thiele DJ. The copper regulon of the human fungal pathogen Cryptococcus neoformans H99. Mol Microbiol 2011; 81:1560-76. [PMID: 21819456 DOI: 10.1111/j.1365-2958.2011.07794.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cryptococcus neoformans is a human fungal pathogen that is the causative agent of cryptococcosis and fatal meningitis in immuno-compromised hosts. Recent studies suggest that copper (Cu) acquisition plays an important role in C. neoformans virulence, as mutants that lack Cuf1, which activates the Ctr4 high affinity Cu importer, are hypo-virulent in mouse models. To understand the constellation of Cu-responsive genes in C. neoformans and how their expression might contribute to virulence, we determined the transcript profile of C. neoformans in response to elevated Cu or Cu deficiency. We identified two metallothionein genes (CMT1 and CMT2), encoding cysteine-rich Cu binding and detoxifying proteins, whose expression is dramatically elevated in response to excess Cu. We identified a new C. neoformans Cu transporter, CnCtr1, that is induced by Cu deficiency and is distinct from CnCtr4 and which shows significant phylogenetic relationship to Ctr1 from other fungi. Surprisingly, in contrast to other fungi, we found that induction of both CnCTR1 and CnCTR4 expression under Cu limitation, and CMT1 and CMT2 in response to Cu excess, are dependent on the CnCuf1 Cu metalloregulatory transcription factor. These studies set the stage for the evaluation of the specific Cuf1 target genes required for virulence in C. neoformans.
Collapse
Affiliation(s)
- Chen Ding
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | | | | | | | | | | |
Collapse
|
24
|
|
25
|
Mira NP, Henriques SF, Keller G, Teixeira MC, Matos RG, Arraiano CM, Winge DR, Sá-Correia I. Identification of a DNA-binding site for the transcription factor Haa1, required for Saccharomyces cerevisiae response to acetic acid stress. Nucleic Acids Res 2011; 39:6896-907. [PMID: 21586585 PMCID: PMC3167633 DOI: 10.1093/nar/gkr228] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The transcription factor Haa1 is the main player in reprogramming yeast genomic expression in response to acetic acid stress. Mapping of the promoter region of one of the Haa1-activated genes, TPO3, allowed the identification of an acetic acid responsive element (ACRE) to which Haa1 binds in vivo. The in silico analysis of the promoter regions of the genes of the Haa1-regulon led to the identification of an Haa1-responsive element (HRE) 5'-GNN(G/C)(A/C)(A/G)G(A/G/C)G-3'. Using surface plasmon resonance experiments and electrophoretic mobility shift assays it is demonstrated that Haa1 interacts with high affinity (K(D) of 2 nM) with the HRE motif present in the ACRE region of TPO3 promoter. No significant interaction was found between Haa1 and HRE motifs having adenine nucleotides at positions 6 and 8 (K(D) of 396 and 6780 nM, respectively) suggesting that Haa1p does not recognize these motifs in vivo. A lower affinity of Haa1 toward HRE motifs having mutations in the guanine nucleotides at position 7 and 9 (K(D) of 21 and 119 nM, respectively) was also observed. Altogether, the results obtained indicate that the minimal functional binding site of Haa1 is 5'-(G/C)(A/C)GG(G/C)G-3'. The Haa1-dependent transcriptional regulatory network active in yeast response to acetic acid stress is proposed.
Collapse
Affiliation(s)
- Nuno P Mira
- IBB, Instituto Biotecnologia e Bioengenharia, Center for Biological and Chemical Engineering, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Beaudoin J, Thiele DJ, Labbé S, Puig S. Dissection of the relative contribution of the Schizosaccharomyces pombe Ctr4 and Ctr5 proteins to the copper transport and cell surface delivery functions. MICROBIOLOGY (READING, ENGLAND) 2011; 157:1021-1031. [PMID: 21273250 DOI: 10.1099/mic.0.046854-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Ctr1 family of proteins mediates high-affinity copper (Cu) acquisition in eukaryotic organisms. In the fission yeast Schizosaccharomyces pombe, Cu uptake is carried out by a heteromeric complex formed by the Ctr4 and Ctr5 proteins. Unlike human and Saccharomyces cerevisiae Ctr1 proteins, Ctr4 and Ctr5 are unable to function independently in Cu acquisition. Instead, both proteins physically interact with each other to form a Ctr4-Ctr5 heteromeric complex, and are interdependent for secretion to the plasma membrane and Cu transport activity. In this study, we used S. cerevisiae mutants that are defective in high-affinity Cu uptake to dissect the relative contribution of Ctr4 and Ctr5 to the Cu transport function. Functional complementation and localization assays show that the conserved Met-X(3)-Met motif in transmembrane domain 2 of the Ctr5 protein is dispensable for the functionality of the Ctr4-Ctr5 complex, whereas the Met-X(3)-Met motif in the Ctr4 protein is essential for function and for localization of the hetero-complex to the plasma membrane. Moreover, Ctr4/Ctr5 chimeric proteins reveal unique properties found either in Ctr4 or in Ctr5, and are sufficient for Cu uptake on the cell surface of Sch. pombe cells. Functional chimeras contain the Ctr4 central and Ctr5 carboxyl-terminal domains (CTDs). We propose that the Ctr4 central domain mediates Cu transport in this hetero-complex, whereas the Ctr5 CTD functions in the regulation of trafficking of the Cu transport complex to the cell surface.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Research Drive-LSRC-C134, Durham, NC 27710, USA
| | - Simon Labbé
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), PO Box 73, E-46100 Burjassot, Valencia, Spain
| |
Collapse
|
27
|
Copper-dependent trafficking of the Ctr4-Ctr5 copper transporting complex. PLoS One 2010; 5:e11964. [PMID: 20694150 PMCID: PMC2915924 DOI: 10.1371/journal.pone.0011964] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2010] [Accepted: 07/13/2010] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND In Schizosaccharomyces pombe, copper uptake is carried out by a heteromeric complex formed by the Ctr4 and Ctr5 proteins. Copper-induced differential subcellular localization may play a critical role with respect to fine tuning the number of Ctr4 and Ctr5 molecules at the cell surface. METHODOLOGY/PRINCIPAL FINDINGS We have developed a bimolecular fluorescence complementation (BiFC) assay to analyze protein-protein interactions in vivo in S. pombe. The assay is based on the observation that N- and C-terminal subfragments of the Venus fluorescent protein can reconstitute a functional fluorophore only when they are brought into tight contact. Wild-type copies of the ctr4(+) and ctr5(+) genes were inserted downstream of and in-frame with the nonfluorescent C-terminal (VC) and N-terminal (VN) coding fragments of Venus, respectively. Co-expression of Ctr4-VC and Ctr5-VN fusion proteins allowed their detection at the plasma membrane of copper-limited cells. Similarly, cells co-expressing Ctr4-VN and Ctr4-VC in the presence of Ctr5-Myc(12) displayed a fluorescence signal at the plasma membrane. In contrast, Ctr5-VN and Ctr5-VC co-expressed in the presence of Ctr4-Flag(2) failed to be visualized at the plasma membrane, suggesting a requirement for a combination of two Ctr4 molecules with one Ctr5 molecule. We found that plasma membrane-located Ctr4-VC-Ctr5-VN fluorescent complexes were internalized when the cells were exposed to high levels of copper. The copper-induced internalization of Ctr4-VC-Ctr5-VN complexes was not dependent on de novo protein synthesis. When cells were transferred back from high to low copper levels, there was reappearance of the BiFC fluorescent signal at the plasma membrane. SIGNIFICANCE These findings reveal a copper-dependent internalization and recycling of the heteromeric Ctr4-Ctr5 complex as a function of copper availability.
Collapse
|
28
|
Labbé S. Simon Labbé's work on iron and copper homeostasis. World J Biol Chem 2010; 1:196-200. [PMID: 21541004 PMCID: PMC3083951 DOI: 10.4331/wjbc.v1.i5.196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 05/18/2010] [Accepted: 05/25/2010] [Indexed: 02/05/2023] Open
Abstract
Iron and copper have a wealth of functions in biological systems, which makes them essential micronutrients for all living organisms. Defects in iron and copper homeostasis are directly responsible for diseases, and have been linked to impaired development, metabolic syndromes and fungal virulence. Consequently, it is crucial to gain a comprehensive understanding of the molecular bases of iron- and copper-dependent proteins in living systems. Simon Labbé maintains parallel programs on iron and copper homeostasis using the fission yeast Schizosaccharomyces pombe (Schiz. pombe) as a model system. The study of fission yeast transition-metal metabolism has been successful, not only in discerning the genes and pathways functioning in Schiz. pombe, but also the genes and pathways that are active in mammalian systems and for other fungi.
Collapse
Affiliation(s)
- Simon Labbé
- Simon Labbé, Department of Biochemistry, Faculty of Medicine, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada
| |
Collapse
|
29
|
Iron-dependent remodeling of fungal metabolic pathways associated with ferrichrome biosynthesis. Appl Environ Microbiol 2010; 76:3806-17. [PMID: 20435771 DOI: 10.1128/aem.00659-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe excretes and accumulates the hydroxamate-type siderophore ferrichrome. The sib1(+) and sib2(+) genes encode, respectively, a siderophore synthetase and an l-ornithine N(5)-oxygenase that participate in ferrichrome biosynthesis. In the present report, we demonstrate that sib1(+) and sib2(+) are repressed by the GATA-type transcriptional repressor Fep1 in response to high levels of iron. We further found that the loss of Fep1 results in increased ferrichrome production. We showed that a sib1Delta sib2Delta mutant strain exhibits a severe growth defect on iron-poor media. We determined that two metabolic pathways are involved in biosynthesis of ornithine, an obligatory precursor of ferrichrome. Ornithine is produced by hydrolysis of arginine by the Car1 and Car3 proteins. Although car3(+) was constitutively expressed, car1(+) transcription levels were repressed upon exposure to iron, with a concomitant decrease of Car1 arginase activity. Ornithine is also generated by transformation of glutamate, which itself is produced by two separate biosynthetic pathways which are transcriptionally regulated by iron in an opposite fashion. In one pathway, the glutamate dehydrogenase Gdh1, which produces glutamate from 2-ketoglutarate, was repressed under iron-replete conditions in a Fep1-dependent manner. The other pathway involves two coupled enzymes, glutamine synthetase Gln1 and Fe-S cluster-containing glutamate synthase Glt1, which were both repressed under iron-limiting conditions but were expressed under iron-replete conditions. Collectively, these results indicate that under conditions of iron deprivation, yeast remodels metabolic pathways linked to ferrichrome synthesis in order to limit iron utilization without compromising siderophore production and its ability to sequester iron from the environment.
Collapse
|
30
|
|
31
|
Nakagawa Y, Kikuchi S, Sakamoto Y, Yano A. Identification and characterization of CcCTR1, a copper uptake transporter-like gene, in Coprinopsis cinerea. Microbiol Res 2009; 165:276-87. [PMID: 19716688 DOI: 10.1016/j.micres.2009.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 05/12/2009] [Accepted: 05/21/2009] [Indexed: 11/16/2022]
Abstract
Copper (Cu) is an essential element for the physiological function of organisms. In basidiomycetes, Cu is necessary for the production of phenol oxidase enzymes such as laccase and tyrosinase. We isolated and characterized two genes, CcCTR1 and -2, from the model basidiomycete Coprinopsis cinerea. CcCTR1 and -2 showed similarity to the Cu transporter CTR1 in Saccharomyces cerevisiae. Both CcCTRs had a MLxxM motif that is conserved in other CTR homologs. The addition of Cu to a liquid culture of C. cinerea decreased the mRNA accumulation of CcCTR1 and -2. Heterologous expression of CcCTR1 in S. cerevisiae increased Cu sensitivity, suggesting that CcCTR1 is a Cu uptake transporter. Together, these results suggest that CcCTR1 plays an important role in Cu accumulation in C. cinerea.
Collapse
Affiliation(s)
- Yuko Nakagawa
- Iwate Biotechnology Research Center, 22-174-4 Narita, Kitakami-shi, Iwate 024-0003, Japan.
| | | | | | | |
Collapse
|
32
|
Balamurugan K, Schaffner W. Regulation of Metallothionein Gene Expression. METALLOTHIONEINS AND RELATED CHELATORS 2009. [DOI: 10.1039/9781847559531-00031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Organisms from bacteria to humans use elaborate systems to regulate levels of bioavailable zinc, copper, and other essential metals. An excess of them, or even traces of non-essential metals such as cadmium and mercury, can be highly toxic. Metallothioneins (MTs), short, cysteine-rich proteins, play pivotal roles in metal homeostasis and detoxification. With their sulfhydryl groups they avidly bind toxic metals and also play a role in cellular redox balance and radical scavenging. The intracellular concentration of MTs is adjusted to cellular demand primarily via regulated transcription. Especially upon heavy metal load, metallothionein gene transcription is strongly induced. From insects to mammals, the major regulator of MT transcription is MTF-1 (metal-responsive transcription factor 1), a zinc finger protein that binds to specific DNA sequence motifs (MREs) in the promoters of MT genes and other metal-regulated genes. This chapter provides an overview of our current knowledge on the expression and regulation of MT genes in higher eukaryotes, with some reference also to fungi which apparently have independently evolved their own regulatory systems.
Collapse
Affiliation(s)
- Kuppusamy Balamurugan
- Institute of Molecular Biology, University of Zürich Winterthurerstrasse 190 CH-8057 Zürich Switzerland
| | - Walter Schaffner
- Institute of Molecular Biology, University of Zürich Winterthurerstrasse 190 CH-8057 Zürich Switzerland
| |
Collapse
|
33
|
Copper distributed by Atx1 is available to copper amine oxidase 1 in Schizosaccharomyces pombe. EUKARYOTIC CELL 2008; 7:1781-94. [PMID: 18723604 DOI: 10.1128/ec.00230-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Copper amine oxidases (CAOs) have been proposed to be involved in the metabolism of xenobiotic and biogenic amines. The requirement for copper is absolute for their activity. In the fission yeast Schizosaccharomyces pombe, cao1(+) and cao2(+) genes are predicted to encode members of the CAO family. While both genes are expressed in wild-type cells, we determined that the expression of only cao1(+) but not cao2(+) results in the production of an active enzyme. Site-directed mutagenesis identified three histidine residues within the C-terminal region of Cao1 that are necessary for amine oxidase activity. By use of a cao1(+)-GFP allele that retained wild-type function, Cao1-GFP was localized in the cytosol (GFP is green fluorescent protein). Under copper-limiting conditions, disruption of ctr4(+), ctr5(+), and cuf1(+) produced a defect in amine oxidase activity, indicating that a functionally active Cao1 requires Ctr4/5-mediated copper transport and the transcription factor Cuf1. Likewise, atx1 null cells exhibited substantially decreased levels of amine oxidase activity. In contrast, deletion of ccc2, cox17, and pccs had no significant effect on Cao1 activity. Residual amine oxidase activity in cells lacking atx1(+) can be restored to normal levels by returning an atx1(+) allele, underscoring the critical importance of the presence of Atx1 in cells. Using two-hybrid analysis, we demonstrated that Cao1 physically interacts with Atx1 and that this association is comparable to that of Atx1 with the N-terminal region of Ccc2. Collectively, these results describe the first example of the ability of Atx1 to act as a copper carrier for a molecule other than Ccc2 and its critical role in delivering copper to Cao1.
Collapse
|
34
|
Key function for the CCAAT-binding factor Php4 to regulate gene expression in response to iron deficiency in fission yeast. EUKARYOTIC CELL 2008; 7:493-508. [PMID: 18223116 DOI: 10.1128/ec.00446-07] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The fission yeast Schizosaccharomyces pombe responds to the deprivation of iron by inducing the expression of the php4+ gene, which encodes a negative regulatory subunit of the heteromeric CCAAT-binding factor. Once formed, the Php2/3/4/5 transcription complex is required to inactivate a subset of genes encoding iron-using proteins. Here, we used a pan-S. pombe microarray to study the transcriptional response to iron starvation and identified 86 genes that exhibit php4+-dependent changes on a genome-wide scale. One of these genes encodes the iron-responsive transcriptional repressor Fep1, whose mRNA levels were decreased after treatment with the permeant iron chelator 2,2'-dipyridyl. In addition, several genes encoding the components of iron-dependent biochemical pathways, including the tricarboxylic acid cycle, mitochondrial respiration, amino acid biosynthesis, and oxidative stress defense, were downregulated in response to iron deficiency. Furthermore, Php4 repressed transcription when brought to a promoter using a yeast DNA-binding domain, and iron deprivation was required for this repression. On the other hand, Php4 was constitutively active when glutathione levels were depleted within the cell. Based on these and previous results, we propose that iron-dependent inactivation of Php4 is regulated at two distinct levels: first, at the transcriptional level by the iron-responsive GATA factor Fep1 and second, at the posttranscriptional level by a mechanism yet to be identified, which inhibits Php4-mediated repressive function when iron is abundant.
Collapse
|
35
|
Abstract
In fungal cells, transcriptional regulatory mechanisms play a central role in both the homeostatic regulation of the essential metals iron, copper and zinc and in the detoxification of heavy metal ions such as cadmium. Fungi detect changes in metal ion levels using unique metallo-regulatory factors whose activity is responsive to the cellular metal ion status. New studies have revealed that these factors not only regulate the expression of genes required for metal ion acquisition, storage or detoxification but also globally remodel metabolism to conserve metal ions or protect against metal toxicity. This review focuses on the mechanisms metallo-regulators use to up- and down-regulate gene expression.
Collapse
Affiliation(s)
- Amanda J Bird
- Division of Hematology, Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
| |
Collapse
|
36
|
Rustici G, van Bakel H, Lackner DH, Holstege FC, Wijmenga C, Bähler J, Brazma A. Global transcriptional responses of fission and budding yeast to changes in copper and iron levels: a comparative study. Genome Biol 2007; 8:R73. [PMID: 17477863 PMCID: PMC1929147 DOI: 10.1186/gb-2007-8-5-r73] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 01/31/2007] [Accepted: 05/03/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent studies in comparative genomics demonstrate that interspecies comparison represents a powerful tool for identifying both conserved and specialized biologic processes across large evolutionary distances. All cells must adjust to environmental fluctuations in metal levels, because levels that are too low or too high can be detrimental. Here we explore the conservation of metal homoeostasis in two distantly related yeasts. RESULTS We examined genome-wide gene expression responses to changing copper and iron levels in budding and fission yeast using DNA microarrays. The comparison reveals conservation of only a small core set of genes, defining the copper and iron regulons, with a larger number of additional genes being specific for each species. Novel regulatory targets were identified in Schizosaccharomyces pombe for Cuf1p (pex7 and SPAC3G6.05) and Fep1p (srx1, sib1, sib2, rds1, isu1, SPBC27B12.03c, SPAC1F8.02c, and SPBC947.05c). We also present evidence refuting a direct role of Cuf1p in the repression of genes involved in iron uptake. Remarkable differences were detected in responses of the two yeasts to excess copper, probably reflecting evolutionary adaptation to different environments. CONCLUSION The considerable evolutionary distance between budding and fission yeast resulted in substantial diversion in the regulation of copper and iron homeostasis. Despite these differences, the conserved regulation of a core set of genes involved in the uptake of these metals provides valuable clues to key features of metal metabolism.
Collapse
Affiliation(s)
- Gabriella Rustici
- EMBL Outstation-Hinxton, European Bioinformatics Institute, Cambridge CB10 1SD, UK
- Cancer Research UK Fission Yeast Functional Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK
| | - Harm van Bakel
- Complex Genetics Group, UMC Utrecht, Department of Biomedical Genetics, 3584 CG Utrecht, The Netherlands
- Genomics Laboratory, UMC Utrecht, Department for Physiological Chemistry, 3584 CG Utrecht, The Netherlands
| | - Daniel H Lackner
- Cancer Research UK Fission Yeast Functional Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK
| | - Frank C Holstege
- Genomics Laboratory, UMC Utrecht, Department for Physiological Chemistry, 3584 CG Utrecht, The Netherlands
| | - Cisca Wijmenga
- Complex Genetics Group, UMC Utrecht, Department of Biomedical Genetics, 3584 CG Utrecht, The Netherlands
- Genetics Department, University Medical Center Groningen, Groningen, The Netherlands
| | - Jürg Bähler
- Cancer Research UK Fission Yeast Functional Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK
| | - Alvis Brazma
- EMBL Outstation-Hinxton, European Bioinformatics Institute, Cambridge CB10 1SD, UK
| |
Collapse
|
37
|
Beaudoin J, Labbé S. Crm1-mediated nuclear export of the Schizosaccharomyces pombe transcription factor Cuf1 during a shift from low to high copper concentrations. EUKARYOTIC CELL 2007; 6:764-75. [PMID: 17384198 PMCID: PMC1899832 DOI: 10.1128/ec.00002-07] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/15/2007] [Indexed: 01/16/2023]
Abstract
In this study, we examine the fate of the nuclear pool of the Schizosaccharomyces pombe transcription factor Cuf1 in response to variations in copper levels. A nuclear pool of Cuf1-green fluorescent protein (GFP) was generated by expressing a functional cuf1(+)-GFP allele in the presence of a copper chelator. We then extinguished cuf1(+)-GFP expression and tracked the changes in the localization of the nuclear pool of Cuf1-GFP in the presence of low or high copper concentrations. Treating cells with copper as well as silver ions resulted in the nuclear export of Cuf1. We identified a leucine-rich nuclear export signal (NES), (349)LAALNHISAL(358), within the C-terminal region of Cuf1. Mutations in this sequence abrogated Cuf1 export from the nucleus. Furthermore, amino acid substitutions that impair Cuf1 NES function resulted in increased target gene expression and a concomitant cellular hypersensitivity to copper. Export of the wild-type Cuf1 protein was inhibited by leptomycin B (LMB), a specific inhibitor of the nuclear export protein Crm1. We further show that cells expressing a temperature-sensitive mutation in crm1(+) exhibit increased nuclear accumulation of Cuf1 at the nonpermissive temperature. Although wild-type Cuf1 is localized in the nucleus in both conditions, we observed that the protein can still be inactivated by copper, resulting in the repression of ctr4(+) gene expression in the presence of exogenous copper. These results demonstrate that nuclear accumulation of Cuf1 per se is not sufficient to cause the unregulated expression of the copper transport genes like ctr4(+). In addition to nuclear localization, a functional Cys-rich domain or NES element in Cuf1 is required to appropriately regulate copper transport gene expression in response to changes in intracellular copper concentration.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, Québec J1H 5N4, Canada
| | | |
Collapse
|
38
|
Waterman SR, Hacham M, Hu G, Zhu X, Park YD, Shin S, Panepinto J, Valyi-Nagy T, Beam C, Husain S, Singh N, Williamson PR. Role of a CUF1/CTR4 copper regulatory axis in the virulence of Cryptococcus neoformans. J Clin Invest 2007; 117:794-802. [PMID: 17290306 PMCID: PMC1784002 DOI: 10.1172/jci30006] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 12/12/2006] [Indexed: 01/18/2023] Open
Abstract
The study of regulatory networks in human pathogens such as Cryptococcus neoformans provides insights into host-pathogen interactions that may allow for correlation of gene expression patterns with clinical outcomes. In the present study, deletion of the cryptococcal copper-dependent transcription factor 1 (Cuf1) led to defects in growth and virulence factor expression in low copper conditions. In mouse models, cuf1Delta strains exhibited reduced dissemination to the brain, but no change in lung growth, suggesting copper is limiting in neurologic infections. To examine this further, a biologic probe of available copper was constructed using the cryptococcal CUF1-dependent copper transporter, CTR4. Fungal cells demonstrated high CTR4 expression levels after phagocytosis by macrophage-like J774.16 cells and during infection of mouse brains, but not lungs, consistent with limited copper availability during neurologic infection. This was extended to human brain infections by demonstrating CTR4 expression during C. neoformans infection of an AIDS patient. Moreover, high CTR4 expression by cryptococcal strains from 24 solid organ transplant patients was associated with dissemination to the CNS. Our results suggest that copper acquisition plays a central role in fungal pathogenesis during neurologic infection and that measurement of stable traits such as CTR4 expression may be useful for risk stratification of individuals with cryptococcosis.
Collapse
Affiliation(s)
- Scott R. Waterman
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Moshe Hacham
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Guowu Hu
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Xudong Zhu
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Yoon-Dong Park
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Soowan Shin
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - John Panepinto
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Tibor Valyi-Nagy
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Craig Beam
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Shahid Husain
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Nina Singh
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Peter R. Williamson
- Section of Infectious Diseases, Department of Medicine, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA.
Department of Pathology, University of Illinois at Chicago Medical Center, Chicago, Illinois, USA.
Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA.
Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Jesse Brown VA Medical Center, Chicago, Illinois, USA
| |
Collapse
|
39
|
Laliberté J, Labbé S. Mechanisms of copper loading on the Schizosaccharomyces pombe copper amine oxidase 1 expressed in Saccharomyces cerevisiae. MICROBIOLOGY (READING, ENGLAND) 2006; 152:2819-2830. [PMID: 16946276 DOI: 10.1099/mic.0.28998-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Copper amine oxidases (CAOs) are found in almost every living kingdom. Although Saccharomyces cerevisiae is one of the few yeast species that lacks an endogenous CAO, heterologous gene expression of CAOs from other organisms produces a functional enzyme. To begin to characterize their function and mechanisms of copper acquisition, two putative cao(+) genes from Schizosaccharomyces pombe were expressed in S. cerevisiae. Expression of spao1(+) resulted in the production of an active enzyme capable of catalysing the oxidative deamination of primary amines. On the other hand, expression of spao2(+) failed to produce an active CAO. Using a functional spao1(+)-GFP fusion allele, the SPAO1 protein was localized in the cytosol. Under copper-limiting conditions, yeast cells harbouring deletions of the MAC1, CTR1 and CTR3 genes were defective in amine oxidase activity. Likewise, atx1Delta null cells exhibited no CAO activity, while ccc2Delta mutant cells exhibited decreased levels of amine oxidase activity, and mutations in cox17Delta and ccs1Delta did not cause any defects in this activity. Copper-deprived S. cerevisiae cells expressing spao1(+) required a functional atx1(+) gene for growth on minimal medium containing ethylamine as the sole nitrogen source. Under these conditions, the inability of the atx1Delta cells to utilize ethylamine correlated with the lack of SPAO1 activity, in spite of the efficient expression of the protein. Cells carrying a disrupted ccc2Delta allele exhibited only weak growth on ethylamine medium containing a copper chelator. The results of these studies reveal that expression of the heterologous spao1(+) gene in S. cerevisiae is required for its growth in medium containing ethylamine as the sole nitrogen source, and that expression of an active Schiz. pombe SPAO1 protein in S. cerevisiae depends on the acquisition of copper through the high-affinity copper transporters Ctr1 and Ctr3, and the copper chaperone Atx1.
Collapse
Affiliation(s)
- Julie Laliberté
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| | - Simon Labbé
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| |
Collapse
|
40
|
Mercier A, Pelletier B, Labbé S. A transcription factor cascade involving Fep1 and the CCAAT-binding factor Php4 regulates gene expression in response to iron deficiency in the fission yeast Schizosaccharomyces pombe. EUKARYOTIC CELL 2006; 5:1866-81. [PMID: 16963626 PMCID: PMC1694796 DOI: 10.1128/ec.00199-06] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have identified genes encoding candidate proteins involved in iron storage (pcl1+), the tricarboxylic acid cycle (sdh4+), and iron-sulfur cluster assembly (isa1+) that are negatively regulated in response to iron deprivation. Promoter deletion and site-directed mutagenesis permitted identification of a new cis-regulatory element in the promoter region of the pcl1+ gene. This cis-acting regulatory sequence containing the pentanucleotide sequence CCAAT is responsible for transcriptional repression of pcl1+ under low iron supply conditions. In Schizosaccharomyces pombe, the CCAAT-binding factor is a heteromeric DNA-binding complex that contains three subunits, designated Php2, Php3, and Php5. Inactivation of the php2+ locus negatively affects the transcriptional competency of pcl1+. A fourth subunit, designated Php4, is not essential for the transcriptional activation of target genes under basal and iron-replete conditions. We demonstrate that, in response to iron-limiting conditions, Php4 is required for down-regulation of pcl1+, sdh4+, and isa1+ mRNA levels. In vivo RNase protection studies reveal that the expression of php4+ is negatively regulated by iron and that this regulated expression requires a functional fep1+ gene. The results of these studies reveal that Fep1 represses php4+ expression in response to iron. In contrast, when iron is scarce, Fep1 becomes inactive and php4+ is expressed to act as a regulatory subunit of the CCAAT-binding factor that is required to block pcl1+, sdh4+, and isa1+ gene transcription.
Collapse
Affiliation(s)
- Alexandre Mercier
- Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, 3001 12e Ave. Nord, Sherbrooke, Québec J1H 5N4, Canada
| | | | | |
Collapse
|
41
|
Beaudoin J, Labbé S. Copper induces cytoplasmic retention of fission yeast transcription factor cuf1. EUKARYOTIC CELL 2006; 5:277-92. [PMID: 16467469 PMCID: PMC1405903 DOI: 10.1128/ec.5.2.277-292.2006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Copper homeostasis within the cell is established and preserved by different mechanisms. Changes in gene expression constitute a way of maintaining this homeostasis. In Schizosaccharomyces pombe, the Cuf1 transcription factor is critical for the activation of copper transport gene expression under conditions of copper starvation. However, in the presence of elevated intracellular levels of copper, the mechanism of Cuf1 inactivation to turn off gene expression remains unclear. In this study, we provide evidence that inactivation of copper transport gene expression by Cuf1 is achieved through a copper-dependent, cytosolic retention of Cuf1. We identify a minimal nuclear localization sequence (NLS) between amino acids 11 to 53 within the Cuf1 N terminus. Deletion of this region and specific mutation of the Lys13, Arg16, Arg19, Lys24, Arg28, Lys45, Arg47, Arg50, and Arg53 residues to alanine within this putative NLS is sufficient to abrogate nuclear targeting of Cuf1. Under conditions of copper starvation, Cuf1 resides in the nucleus. However, in the presence of excess copper as well as silver ions, Cuf1 is sequestered in the cytoplasm, a process which requires the putative copper binding motif, 328Cys-X-Cys-X3-Cys-X-Cys-X2-Cys-X2-His342 (designated C-rich), within the C-terminal region of Cuf1. Deletion of this region and mutation of the Cys residues within the C-rich motif result in constitutive nuclear localization of Cuf1. By coexpressing the Cuf1 N terminus with its C terminus in trans and by using a two-hybrid assay, we show that these domains physically interact with each other in a copper-dependent manner. We propose a model wherein copper induces conformational changes in Cuf1 that promote a physical interaction between the Cuf1 N terminus and the C-rich motif in the C terminus that masks the NLS. Cuf1 is thereby sequestered in the cytosol under conditions of copper excess, thereby extinguishing copper transport gene expression.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie, Faculté de médecine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, Québec J1H 5N4, Canada
| | | |
Collapse
|
42
|
|
43
|
Juang HH. Modulation of iron on mitochondrial aconitase expression in human prostatic carcinoma cells. Mol Cell Biochem 2005; 265:185-94. [PMID: 15543948 DOI: 10.1023/b:mcbi.0000044395.59739.1f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The mitochondrial aconitase (mACON) containing a [4Fe-4S] cluster is regarded as the key enzyme for citrate oxidation in the epithelial cells of human prostate. In vitro studies using the human prostatic carcinoma cells, PC-3 cells, found that both hemin and ferric ammonium citrate (FAC) significantly increased mACON enzymatic activity and gene expression. The effect of FAC on mACON was enhanced 2-fold by co-treating with ascorbic acid but blocked by co-treating with iron chelator, deferoxamine mesylate. Hemin treatments blocked 30% of citrate secretion from PC-3 cells but upregualted 2-fold of intracellular ATP biosynthesis. Results from reporter assay by using a cytomegalovirus enhance/promoter driven luciferase mRNA ligated to the iron response element (IRE) of mACON as a reporter construct demonstrated that modulation of FAC on gene translation of mACON gene is dependent on the IRE. Transient gene expression assays indicated that upregulation of mACON gene transcription by FAC may through the putative antioxidant response element (ARE) signal pathway. This study provides the first evidence of the biologic mechanism of human mACON gene translation/transcription and suggests a regulatory link between the energy utilization and the iron metabolism in human prostatic carcinoma cells.
Collapse
Affiliation(s)
- Horng-Heng Juang
- Department of Anatomy, Chang Gung University, Tao-Yuan 333, Taiwan, ROC.
| |
Collapse
|
44
|
Rutherford JC, Bird AJ. Metal-responsive transcription factors that regulate iron, zinc, and copper homeostasis in eukaryotic cells. EUKARYOTIC CELL 2004; 3:1-13. [PMID: 14871932 PMCID: PMC329510 DOI: 10.1128/ec.3.1.1-13.2004] [Citation(s) in RCA: 197] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Julian C Rutherford
- Division of Hematology, Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA
| | | |
Collapse
|
45
|
Laliberté J, Whitson LJ, Beaudoin J, Holloway SP, Hart PJ, Labbé S. The Schizosaccharomyces pombe Pccs protein functions in both copper trafficking and metal detoxification pathways. J Biol Chem 2004; 279:28744-55. [PMID: 15107426 DOI: 10.1074/jbc.m403426200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Because copper is both an essential cofactor and a toxic metal, different strategies have evolved to appropriately regulate its homeostasis as a function of changing environmental copper levels. In this report, we describe a metallochaperone-like protein from Schizosaccharomyces pombe that maintains the delicate balance between essentiality and toxicity. This protein, designated Pccs, has four distinct domains. SOD activity assays reveal that the first three domains of Pccs are necessary and sufficient to deliver copper to its target, copper-zinc superoxide dismutase (SOD1). Pccs domain IV, which is absent in Saccharomyces cerevisiae CCS1, contains seventeen cysteine residues, eight pairs of which are in a potential metal coordination arrangement, Cys-Cys. We show that S. cerevisiae ace1Delta mutant cells expressing the full-length Pccs molecule are resistant to copper toxicity. Furthermore, we demonstrate that the Pccs domain IV enhances copper resistance of the ace1Delta cells by an order of magnitude compared with that observed in the same strain expressing a pccs+ I-II-III allele encoding Pccs domains I-III. We consistently found that S. pombe cells disrupted in the pccs+ gene exhibit an increased sensitivity to copper and cadmium. Furthermore, we demonstrate that overexpression of pccs+ is associated with increased copper resistance in fission yeast cells. Taken together, our findings suggest that Pccs activates apo-SOD1 under copper-limiting conditions through the use of its first three domains and protects cells against metal ion toxicity via its fourth domain.
Collapse
Affiliation(s)
- Julie Laliberté
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| | | | | | | | | | | |
Collapse
|
46
|
Rees EM, Thiele DJ. From aging to virulence: forging connections through the study of copper homeostasis in eukaryotic microorganisms. Curr Opin Microbiol 2004; 7:175-84. [PMID: 15063856 DOI: 10.1016/j.mib.2004.02.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent years have witnessed an explosion in the breadth of investigations on transition metal homeostasis and the subsequent depth of our understanding of metals in biology. Many genes and proteins that serve in the uptake, distribution, sensing and detoxification of one such transition metal, copper, have been identified. Through genetic and biochemical studies, the molecular details of copper uptake are being elucidated, and evidence suggests a largely conserved mechanism for copper acquisition and distribution from yeast to humans. Investigations of the mitochondrial copper pathway reveal the complexity surrounding copper delivery to cytochrome oxidase and highlight additional roles for some of the participants in copper homeostasis, such as a copper chaperone that influences the subcellular distribution of its target for copper incorporation. Furthermore, our understanding of the structure and function of copper transporters, chaperones and cupro-proteins, coupled with the emergence of additional model systems, is providing surprising examples of the integration of copper homeostasis with other physiological and pathophysiological processes and states, such as cancer, aging and virulence.
Collapse
Affiliation(s)
- Erin M Rees
- Department of Pharmacology and Cancer Biology, and the Sarah W Stedman Nutrition and Metabolism Center, Duke University Medical Center, 3813 Research Drive, Durham, NC 27710, USA
| | | |
Collapse
|
47
|
Znaidi S, Pelletier B, Mukai Y, Labbé S. The Schizosaccharomyces pombe corepressor Tup11 interacts with the iron-responsive transcription factor Fep1. J Biol Chem 2004; 279:9462-74. [PMID: 14668334 DOI: 10.1074/jbc.m312787200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Schizosaccharomyces pombe fep1(+) gene encodes a GATA transcription factor that represses the expression of iron transport genes in response to elevated iron concentrations. This transcriptional response is altered only in strains harboring a combined deletion of both tup11(+) and tup12(+) genes. This suggests that Tup11 is capable of negatively regulating iron transport gene expression in the absence of Tup12 and vice versa. The tup11(+)- and tup12(+)-encoded proteins resemble the Saccharomyces cerevisiae Tup1 corepressor. Using yeast two-hybrid analysis we show that Tup11 and Fep1 physically interact with each other. The C-terminal region from amino acids 242 to 564 of Fep1 is required for interaction with Tup11. Within this region, a minimal domain encompassing amino acids 405-541 was sufficient for Tup11-Fep1 association. Deletion mapping analysis revealed that the WD40-repeat sequence motifs of Tup11 are necessary for its interaction with Fep1. Analysis of Tup11 mutants with single amino acid substitutions in the WD40 repeats suggested that the Fep1 transcription factor interacts with a putative flat upper surface on the predicted beta-propeller structure of this motif. Further analysis by in vivo coimmunoprecipitation showed that Tup11 and Fep1 are physically associated. In vitro pull-down experiments further verified a direct interaction between the Fep1 C terminus and the Tup11 C-terminal WD40 repeat domain. Taken together, these results describe the first example of a physical interaction between a corepressor and an iron-sensing factor controlling the expression of iron uptake genes.
Collapse
Affiliation(s)
- Sadri Znaidi
- Département de Biochimie, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | | | | | | |
Collapse
|
48
|
Mitsuzawa H, Ishihama A. RNA polymerase II transcription apparatus in Schizosaccharomyces pombe. Curr Genet 2003; 44:287-94. [PMID: 14574615 DOI: 10.1007/s00294-003-0446-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2003] [Revised: 08/27/2003] [Accepted: 09/04/2003] [Indexed: 10/26/2022]
Abstract
Eukaryotic RNA polymerase II (Pol II) transcription apparatus is a multi-protein complex consisting of the RNA polymerase II core enzyme (12 subunits), general transcription factors, the mediator, and some other specific accessory factors with regulatory functions. After genome sequencing was completed, the fission yeast Schizosaccharomyces pombe was recognized as a good model organism to study the Pol II transcription apparatus, because most genetic methods developed with the budding yeast Saccharomyces cerevisiae are applicable but the genetic systems of Sch. pombe, including transcription, are closer to those in higher eukaryotes. Recent studies on components of the Sch. pombe basal transcription machinery not only revealed a number of properties common in other eukaryotes but also illuminated some features unique to Sch. pombe. Convergence of information from both yeasts will provide us with a more general understanding of eukaryotic transcription.
Collapse
Affiliation(s)
- Hiroshi Mitsuzawa
- Department of Molecular Genetics, National Institute of Genetics, Mishima, 411-8540, Shizuoka, Japan
| | | |
Collapse
|
49
|
Pelletier B, Beaudoin J, Philpott CC, Labbé S. Fep1 represses expression of the fission yeast Schizosaccharomyces pombe siderophore-iron transport system. Nucleic Acids Res 2003; 31:4332-44. [PMID: 12888492 PMCID: PMC169938 DOI: 10.1093/nar/gkg647] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2003] [Revised: 06/10/2003] [Accepted: 06/10/2003] [Indexed: 12/16/2022] Open
Abstract
When iron repletes, Schizosaccharomyces pombe cells repress transcription of genes encoding components involved in the reductive iron transport system. Fep1 mediates this transcriptional control by interacting specifically with GATA-type cis-acting elements. To further investigate the role that Fep1 plays in iron homeostasis, we searched for additional Fep1-regulated genes. We found that str1+ is subject to negative transcriptional regulation, which is exerted through binding of Fep1 to a single GATA element in the str1+ promoter. Introduction of str1+ into a Saccharomyces cerevisiae fet3Delta arn1-4Delta strain led to assimilation of iron from ferrichrome, revealing that Str1 functions as a siderophore-iron transporter in S.pombe. We also identified two additional target genes of Fep1, named str2+ and str3+. We demonstrate that the str1+, str2+ and str3+ genes share a common promoter element, 5'-(A/T)GATAA-3'. We found that the N-terminal 241 residue segment of Fep1 expressed in Escherichia coli specifically interacts with the 5'-(A/T)GATAA-3' element present in each of these promoters. Consistent with this, constitutive high level str1+, str2+ and str3+ gene expression was observed in a fep1Delta mutant strain. Taken together, these results demonstrate that Fep1 occupies a central role in coordinating transcriptional regulation of genes encoding components of the reductive and non-reductive iron transport systems in fission yeast.
Collapse
Affiliation(s)
- Benoit Pelletier
- Département de Biochimie, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | | | | | | |
Collapse
|
50
|
Beaudoin J, Mercier A, Langlois R, Labbé S. The Schizosaccharomyces pombe Cuf1 is composed of functional modules from two distinct classes of copper metalloregulatory transcription factors. J Biol Chem 2003; 278:14565-77. [PMID: 12578838 DOI: 10.1074/jbc.m300861200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In fission yeast, the genes encoding proteins that are components of the copper transporter family are controlled at the transcriptional level by the Cuf1 transcription factor. Under low copper availability, Cuf1 induces expression of the copper transporter genes. In contrast, sufficient levels of copper inactivate Cuf1 and expression of its target genes. Our study reveals that Cuf1 harbors a putative copper-binding motif, Cys-X-Cys-X(3)-Cys-X-Cys-X(2)-Cys-X(2)-His, within its carboxyl-terminal region to sense changing environmental copper levels. Binding studies reveal that the amino-terminal 174-residue segment of Cuf1 expressed as a fusion protein in Escherichia coli specifically interacts with the cis-acting copper transporter promoter element CuSE (copper-signaling element). Within this region, the first 61 amino acids of Cuf1 exhibit more overall homology to the Saccharomyces cerevisiae Ace1 copper-detoxifying factor (from residues 1 to 63) than to Mac1, its functional ortholog. Consistently, we demonstrate that a chimeric Cuf1 protein bearing the amino-terminal 63-residue segment of Ace1 complements cuf1 Delta null phenotypes. Furthermore, we show that Schizosaccharomyces pombe cuf1Delta mutant cells expressing the full-length S. cerevisiae Ace1 protein are hypersensitive to copper ions, with a concomitant up-regulation of CuSE-mediated gene expression in fission yeast. Taken together, these studies reveal that S. cerevisiae Ace1 1-63 is functionally exchangeable with S. pombe Cuf1 1-61, and the nature of the amino acids located downstream of this amino-terminal conserved region may be crucial in dictating the type of regulatory response required to establish and maintain copper homeostasis.
Collapse
Affiliation(s)
- Jude Beaudoin
- Département de Biochimie and Sherbrooke Positron Emission Tomography Center, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | | | | | | |
Collapse
|