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Seike T, Sakata N, Shimoda C, Niki H, Furusawa C. The sixth transmembrane region of a pheromone G-protein coupled receptor, Map3, is implicated in discrimination of closely related pheromones in Schizosaccharomyces pombe. Genetics 2021; 219:6371190. [PMID: 34849842 DOI: 10.1093/genetics/iyab150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 09/06/2021] [Indexed: 11/14/2022] Open
Abstract
Most sexually reproducing organisms have the ability to recognize individuals of the same species. In ascomycete fungi including yeasts, mating between cells of opposite mating type depends on the molecular recognition of two peptidyl mating pheromones by their corresponding G-protein coupled receptors (GPCRs). Although such pheromone/receptor systems are likely to function in both mate choice and prezygotic isolation, very few studies have focused on the stringency of pheromone receptors. The fission yeast Schizosaccharomyces pombe has two mating types, Plus (P) and Minus (M). Here, we investigated the stringency of the two GPCRs, Mam2 and Map3, for their respective pheromones, P-factor and M-factor, in fission yeast. First, we switched GPCRs between S. pombe and the closely related species Schizosaccharomyces octosporus, which showed that SoMam2 (Mam2 of S. octosporus) is partially functional in S. pombe, whereas SoMap3 (Map3 of S. octosporus) is not interchangeable. Next, we swapped individual domains of Mam2 and Map3 with the respective domains in SoMam2 and SoMap3, which revealed differences between the receptors both in the intracellular regions that regulate the downstream signaling of pheromones and in the activation by the pheromone. In particular, we demonstrated that two amino acid residues of Map3, F214 and F215, are key residues important for discrimination of closely related M-factors. Thus, the differences in these two GPCRs might reflect the significantly distinct stringency/flexibility of their respective pheromone/receptor systems; nevertheless, species-specific pheromone recognition remains incomplete.
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Affiliation(s)
- Taisuke Seike
- Center for Biosystems Dynamics Research, RIKEN, Osaka 565-0874, Japan
| | - Natsue Sakata
- Center for Biosystems Dynamics Research, RIKEN, Osaka 565-0874, Japan
| | - Chikashi Shimoda
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Hironori Niki
- Genetic Strains Research Center, National Institute of Genetics, Shizuoka 411-8540, Japan
| | - Chikara Furusawa
- Center for Biosystems Dynamics Research, RIKEN, Osaka 565-0874, Japan.,Universal Biology Institute, The University of Tokyo, Tokyo 113-0033, Japan
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Seike T, Shimoda C, Niki H. Asymmetric diversification of mating pheromones in fission yeast. PLoS Biol 2019; 17:e3000101. [PMID: 30668560 PMCID: PMC6342294 DOI: 10.1371/journal.pbio.3000101] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/19/2018] [Indexed: 01/25/2023] Open
Abstract
In fungi, mating between partners depends on the molecular recognition of two peptidyl mating pheromones by their respective receptors. The fission yeast Schizosaccharomyces pombe (Sp) has two mating types, Plus (P) and Minus (M). The mating pheromones P-factor and M-factor, secreted by P and M cells, are recognized by the receptors mating type auxiliary minus 2 (Mam2) and mating type auxiliary plus 3 (Map3), respectively. Our recent study demonstrated that a few mutations in both M-factor and Map3 can trigger reproductive isolation in S. pombe. Here, we explored the mechanism underlying reproductive isolation through genetic changes of pheromones/receptors in nature. We investigated the diversity of genes encoding the pheromones and their receptor in 150 wild S. pombe strains. Whereas the amino acid sequences of M-factor and Map3 were completely conserved, those of P-factor and Mam2 were very diverse. In addition, the P-factor gene contained varying numbers of tandem repeats of P-factor (4–8 repeats). By exploring the recognition specificity of pheromones between S. pombe and its close relative Schizosaccharomyces octosporus (So), we found that So-M-factor did not have an effect on S. pombe P cells, but So-P-factor had a partial effect on S. pombe M cells. Thus, recognition of M-factor seems to be stringent, whereas that of P-factor is relatively relaxed. We speculate that asymmetric diversification of the two pheromones might be facilitated by the distinctly different specificities of the two receptors. Our findings suggest that M-factor communication plays an important role in defining the species, whereas P-factor communication is able to undergo a certain degree of flexible adaptation–perhaps as a first step toward prezygotic isolation in S. pombe. An asymmetric pheromone/receptor system in the fission yeast Schizosaccharomyces pombe might allow flexible adaptation of pheromones to mutational changes while maintaining stringent recognition for mating partners, perhaps as a first step toward prezygotic mating isolation. The emergence of a new species might occur when two groups can no longer mate. Although such reproductive isolation is considered a key evolutionary process, the mechanisms by which it actually occurs have been confined to conjecture. The two sexes (Plus [P] and Minus [M]) of S. pombe each secrete a pheromone (P-factor and M-factor), which binds to a corresponding receptor (mating type auxiliary minus 2 [Mam2] and mating type auxiliary plus 3 [Map3]) on cells of the opposite sex. The interaction between a pheromone and its receptor is essential for successful mating. Here, we explored conservation of the mating pheromone communication system among 150 wild S. pombe strains of different geographical origins and the closely related species S. octosporus. We found that 1) the M-factor/Map3 interaction was completely conserved, whereas the P-factor/Mam2 interaction was very diverse in the strains investigated, and 2) most of the P-factor variants were functional across species. Thus, we have revealed an asymmetric pheromone/receptor system in fungal mating: namely, whereas M-factor communication operates extremely stringently, P-factor communication has the flexibility to create variations, perhaps facilitating prezygotic isolation in S. pombe.
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Affiliation(s)
- Taisuke Seike
- Genetics Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
- * E-mail:
| | - Chikashi Shimoda
- Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
| | - Hironori Niki
- Genetics Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
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3
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Heistinger L, Moser J, Tatto NE, Valli M, Gasser B, Mattanovich D. Identification and characterization of the Komagataella phaffii mating pheromone genes. FEMS Yeast Res 2018; 18:4987207. [PMID: 29718186 PMCID: PMC5993090 DOI: 10.1093/femsyr/foy051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/24/2018] [Indexed: 12/30/2022] Open
Abstract
The methylotrophic yeast Komagataella phaffii (Pichia pastoris) is a haploid yeast that is able to form diploid cells by mating once nitrogen becomes limiting. Activation of the mating response requires the secretion of a- and α-factor pheromones, which bind to G-protein coupled receptors on cells of opposite mating type. In K. phaffii, the genes coding for the α-factor (MFα), the pheromone surface receptors and the conserved a-factor biogenesis pathway have been annotated previously. Initial homology-based search failed to identify potential a-factor genes (MFA). By using transcriptome data of heterothallic strains under mating conditions, we found two K. phaffiia-factor genes. Deletion of both MFA genes prevented mating of a-type cells. MFA single mutants were still able to mate and activate the mating response pathway in α-type cells. A reporter assay was used to confirm the biological activity of synthetic a- and α-factor peptides. The identification of the a-factor genes enabled the first characterization of the role and regulation of the mating pheromone genes and the response of K. phaffii to synthetic pheromones and will help to gain a better understanding of the mating behavior of K. phaffii.
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Affiliation(s)
- Lina Heistinger
- Christian Doppler Laboratory for Innovative Immunotherapeutics at Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Josef Moser
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria
- School of Bioengineering, University of Applied Sciences FH-Campus, Muthgasse 11, 1190 Vienna, Austria
| | - Nadine E Tatto
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria
- Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Minoska Valli
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria
- Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Brigitte Gasser
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria
- Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Diethard Mattanovich
- Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria
- Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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4
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Dudin O, Merlini L, Martin SG. Spatial focalization of pheromone/MAPK signaling triggers commitment to cell-cell fusion. Genes Dev 2017; 30:2226-2239. [PMID: 27798845 PMCID: PMC5088570 DOI: 10.1101/gad.286922.116] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/21/2016] [Indexed: 12/14/2022]
Abstract
Here, Dudin et al. show that cell fusion does not require a dedicated signal but is triggered by spatial focalization of the same pheromone–GPCR–MAPK signaling cascade that drives earlier mating events in Schizosaccharomyces pombe. Cell fusion is universal in eukaryotes for fertilization and development, but what signals this process is unknown. Here, we show in Schizosaccharomyces pombe that fusion does not require a dedicated signal but is triggered by spatial focalization of the same pheromone–GPCR (G-protein-coupled receptor)–MAPK signaling cascade that drives earlier mating events. Autocrine cells expressing the receptor for their own pheromone trigger fusion attempts independently of cell–cell contact by concentrating pheromone release at the fusion focus, a dynamic actin aster underlying the secretion of cell wall hydrolases. Pheromone receptor and MAPK cascade are similarly enriched at the fusion focus, concomitant with fusion commitment in wild-type mating pairs. This focalization promotes cell fusion by immobilizing the fusion focus, thus driving local cell wall dissolution. We propose that fusion commitment is imposed by a local increase in MAPK concentration at the fusion focus, driven by a positive feedback between fusion focus formation and focalization of pheromone release and perception.
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Affiliation(s)
- Omaya Dudin
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
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fhl1 gene of the fission yeast regulates transcription of meiotic genes and nitrogen starvation response, downstream of the TORC1 pathway. Curr Genet 2016; 63:91-101. [PMID: 27165118 DOI: 10.1007/s00294-016-0607-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 01/07/2023]
Abstract
Environmental changes, such as nutrient limitation or starvation induce different signal transducing pathways, which require coordinated cooperation of several genes. Our previous data revealed that the fhl1 fork-head type transcription factor of the fission yeast could be involved in sporulation, which was typically induced under poor conditions. Since the exact role of Fhl1 in this process was not known, we wanted to identify its downstream targets and to investigate its possible cooperation with another known regulator of sporulation. Gene expression and Northern blot analysis of the fhl1∆ mutant strain revealed the target genes involved in mating and sporulation. Our results also showed that Fhl1 could regulate nutrient sensing, the transporter and permease genes. Since the majority of these genes belonged to the nitrogen starvation response, the possible cooperation of fhl1 and tor2 was also investigated. Comparison of their microarray data and the expression of fhl1 + from a strong promoter in the tor2-ts mutant cells suggested that one part of the target genes are commonly regulated by Fhl1 and Tor2. Since the expression of fhl1 + from a strong promoter could rescue rapamycin and temperature sensitivity and suppressed the hyper-sporulation defect of the tor2-ts mutant cells, we believe that Fhl1 acts in TOR signaling, downstream of Tor2. Thus, this work shed light on certain novel details of the regulation of the sexual processes and a new member of the TOR pathway, but further experiments are needed to confirm the involvement of Fhl1 in nutrient sensing.
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Merlini L, Khalili B, Bendezú FO, Hurwitz D, Vincenzetti V, Vavylonis D, Martin SG. Local Pheromone Release from Dynamic Polarity Sites Underlies Cell-Cell Pairing during Yeast Mating. Curr Biol 2016; 26:1117-25. [PMID: 27020743 DOI: 10.1016/j.cub.2016.02.064] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 02/01/2016] [Accepted: 02/25/2016] [Indexed: 11/19/2022]
Abstract
Cell pairing is central for many processes, including immune defense, neuronal connection, hyphal fusion, and sexual reproduction. How does a cell orient toward a partner, especially when faced with multiple choices? Fission yeast Schizosaccharomyces pombe P and M cells, which respectively express P and M factor pheromones [1, 2], pair during the mating process induced by nitrogen starvation. Engagement of pheromone receptors Map3 and Mam2 [3, 4] with their cognate pheromone ligands leads to activation of the Gα protein Gpa1 to signal sexual differentiation [3, 5, 6]. Prior to cell pairing, the Cdc42 GTPase, a central regulator of cell polarization, forms dynamic zones of activity at the cell periphery at distinct locations over time [7]. Here we show that Cdc42-GTP polarization sites contain the M factor transporter Mam1, the general secretion machinery, which underlies P factor secretion, and Gpa1, suggesting that these are sub-cellular zones of pheromone secretion and signaling. Zone lifetimes scale with pheromone concentration. Computational simulations of pair formation through a fluctuating zone show that the combination of local pheromone release and sensing, short pheromone decay length, and pheromone-dependent zone stabilization leads to efficient pair formation. Consistently, pairing efficiency is reduced in the absence of the P factor protease. Similarly, zone stabilization at reduced pheromone levels, which occurs in the absence of the predicted GTPase-activating protein for Ras, leads to reduction in pairing efficiency. We propose that efficient cell pairing relies on fluctuating local signal emission and perception, which become locked into place through stimulation.
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Affiliation(s)
- Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - Bita Khalili
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
| | - Felipe O Bendezú
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - Daniel Hurwitz
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA; Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | | | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland.
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7
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Molecular coevolution of a sex pheromone and its receptor triggers reproductive isolation in Schizosaccharomyces pombe. Proc Natl Acad Sci U S A 2015; 112:4405-10. [PMID: 25831518 DOI: 10.1073/pnas.1501661112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The diversification of sex pheromones is regarded as one of the causes of prezygotic isolation that results in speciation. In the fission yeast Schizosaccharomyces pombe, the molecular recognition of a peptide pheromone by its receptor plays an essential role in sexual reproduction. We considered that molecular coevolution of a peptide-mating pheromone, M factor, and its receptor, Map3, might be realized by experimentally diversifying these proteins. Here, we report the successful creation of novel mating-type pairs by searching for map3 suppressor mutations that rescued the sterility of M-factor mutants that were previously isolated. Several strong suppressors were found to also recognize WT M factor. The substituted residues of these Map3 suppressors were mapped to F204, F214, and E249, which are likely to be critical residues for M-factor recognition. These critical residues were systematically substituted with each of the other amino acids by in vitro mutagenesis. Ultimately, we successfully obtained three novel mating-type pairs constituting reproductive groups. These novel mating-type pairs could not conjugate with WT maters. Furthermore, no flow of chromosomally integrated drug-resistance genes occurred between the novel and the WT mating pairs, showing that each experimentally created reproductive group [e.g., M factor(V5H) and Map3(F214H)] was isolated from the WT group. In conclusion, we have succeeded in creating an artificial reproductive group that is isolated from the WT group. In keeping with the biological concept of species, the artificial reproductive group is a new species.
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Seike T, Nakamura T, Shimoda C. Distal and proximal actions of peptide pheromone M-factor control different conjugation steps in fission yeast. PLoS One 2013; 8:e69491. [PMID: 23874965 PMCID: PMC3713066 DOI: 10.1371/journal.pone.0069491] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Accepted: 06/10/2013] [Indexed: 11/26/2022] Open
Abstract
Mating pheromone signaling is essential for conjugation between haploid cells of P-type (P-cells) and haploid cells of M-type (M-cells) in Schizosaccharomyces pombe. A peptide pheromone, M-factor, produced by M-cells is recognized by the receptor of P-cells. An M-factor-less mutant, in which the M-factor-encoding genes are deleted, is completely sterile. In liquid culture, sexual agglutination was not observed in the mutant, but it could be recovered by adding exogenous synthetic M-factor, which stimulated expression of the P-type-specific cell adhesion protein, Map4. Exogenous M-factor, however, failed to recover the cell fusion defect in the M-factor-less mutant. When M-factor-less cells were added to a mixture of wild-type P- and M-cells, marked cell aggregates were formed. Notably, M-factor-less mutant cells were also incorporated in these aggregates. In this mixed culture, P-cells conjugated preferentially with M-cells secreting M-factor, and rarely with M-factor-less M-cells. The kinetics of mating parameters in liquid culture revealed that polarized growth commenced from the contact region of opposite mating-type cells. Taken together, these findings indicate that M-factor at a low concentration induces adhesin expression, leading to initial cell-cell adhesion in a type of “distal pheromone action”, but M-factor that is secreted directly in the proximity of the adhered P-cells may be necessary for cell fusion in a type of “proximal pheromone action”.
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Affiliation(s)
- Taisuke Seike
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan.
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Seike T, Yamagishi Y, Iio H, Nakamura T, Shimoda C. Remarkably simple sequence requirement of the M-factor pheromone of Schizosaccharomyces pombe. Genetics 2012; 191:815-25. [PMID: 22542965 PMCID: PMC3389977 DOI: 10.1534/genetics.112.140483] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 04/16/2012] [Indexed: 11/18/2022] Open
Abstract
The mating reaction is triggered by specific pheromones in a wide variety of organisms. Small peptides are used as mating pheromones in yeasts and fungi. In the fission yeast Schizosaccharomyces pombe, M-factor is a C terminally farnesylated nonapeptide secreted from M-cells, and its counterpart, P-factor, is a simple peptide composed of 23 amino acids. The primary structure requirements for the biological activity of pheromone peptides remain to be elucidated. Here, we conducted comprehensive substitution of each of the amino acids in M-factor peptide and inspected the mating ability of these missense mutants. Thirty-five sterile mutants were found among an array of 152 mutants with single amino acid substitutions. Mapping of the mutation sites clearly indicated that the sterile mutants were associated exclusively with four amino acid residues (VPYM) in the carboxyl-terminal half. In contrast, the substitution of four amino-terminal residues (YTPK) with any amino acid had no or only a slightly deleterious effect on mating. Furthermore, deletion of the three N-terminal residues caused no sterility, although truncation of a fourth residue had a marked effect. We conclude that a farnesylated hexapeptide (KVPYMC(Far)-OCH(3)) is the minimal M-factor that retains pheromone activity. At least 15 nonfunctional peptides were found to be secreted, suggesting that these mutant M-factor peptides are no longer recognized by the cognate receptor.
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Affiliation(s)
| | - Yoshikazu Yamagishi
- Department of Material Science and Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hideo Iio
- Department of Material Science and Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
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Dheur S, Saupe SJ, Genier S, Vazquez S, Javerzat JP. Role for cohesin in the formation of a heterochromatic domain at fission yeast subtelomeres. Mol Cell Biol 2011; 31:1088-97. [PMID: 21189291 PMCID: PMC3067812 DOI: 10.1128/mcb.01290-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 12/15/2010] [Indexed: 11/20/2022] Open
Abstract
Increasing evidence implicates cohesin in the control of gene expression. Here we report the first analysis of cohesin-dependent gene regulation in fission yeast. Global expression profiling of the mis4-367 cohesin loader mutant identified a small number of upregulated and downregulated genes within subtelomeric domains (SD). These 20- to 40-kb regions between chromosome arm euchromatin and telomere-proximal heterochromatin are characterized by a combination of euchromatin (methylated lysine 4 on histone H3/methylated Tysine 9 on histone H3 [H3K4me]) and heterochromatin (H3K9me) marks. We focused our analysis on the chromosome 1 right SD, which contains several upregulated genes and is bordered on the telomere-distal side by a pair of downregulated genes. We find that the expression changes in the SD also occur in a mutant of the cohesin core component Rad21. Remarkably, mutation of Rad21 results in the depletion of Swi6 binding in the SD. In fact, the Rad21 mutation phenocopied Swi6 loss of function: both mutations led to reduced cohesin binding, reduced H3K9me, and similar gene expression changes in the SD. In particular, expression of the gene pair bordering the SD was dependent both on cohesin and on Swi6. Our data indicate that cohesin participates in the setup of a subtelomeric heterochromatin domain and controls the expression of the genes residing in that domain.
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Affiliation(s)
- Sonia Dheur
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR5095, and Université Victor Segalen Bordeaux 2, Bordeaux F-33077, France
| | - Sven J. Saupe
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR5095, and Université Victor Segalen Bordeaux 2, Bordeaux F-33077, France
| | - Sylvie Genier
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR5095, and Université Victor Segalen Bordeaux 2, Bordeaux F-33077, France
| | - Stéphanie Vazquez
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR5095, and Université Victor Segalen Bordeaux 2, Bordeaux F-33077, France
| | - Jean-Paul Javerzat
- CNRS, Institut de Biochimie et Génétique Cellulaires, UMR5095, and Université Victor Segalen Bordeaux 2, Bordeaux F-33077, France
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Red1 promotes the elimination of meiosis-specific mRNAs in vegetatively growing fission yeast. EMBO J 2011; 30:1027-39. [PMID: 21317872 DOI: 10.1038/emboj.2011.32] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/21/2011] [Indexed: 01/01/2023] Open
Abstract
Meiosis-specific mRNAs are transcribed in vegetative fission yeast, and these meiotic mRNAs are selectively removed from mitotic cells to suppress meiosis. This RNA elimination system requires degradation signal sequences called determinant of selective removal (DSR), an RNA-binding protein Mmi1, polyadenylation factors, and the nuclear exosome. However, the detailed mechanism by which meiotic mRNAs are selectively degraded in mitosis but not meiosis is not understood fully. Here we report that Red1, a novel protein, is essential for elimination of meiotic mRNAs from mitotic cells. A red1 deletion results in the accumulation of a large number of meiotic mRNAs in mitotic cells. Red1 interacts with Mmi1, Pla1, the canonical poly(A) polymerase, and Rrp6, a subunit of the nuclear exosome, and promotes the destabilization of DSR-containing mRNAs. Moreover, Red1 forms nuclear bodies in mitotic cells, and these foci are disassembled during meiosis. These results demonstrate that Red1 is involved in DSR-directed RNA decay to prevent ectopic expression of meiotic mRNAs in vegetative cells.
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Kjærulff S, Andersen NR, Borup MT, Nielsen O. Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G1. Genes Dev 2007; 21:347-59. [PMID: 17289922 PMCID: PMC1785116 DOI: 10.1101/gad.407107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Eukaryotic cells normally differentiate from G(1); here we investigate the mechanism preventing expression of differentiation-specific genes outside G(1). In fission yeast, induction of the transcription factor Ste11 triggers sexual differentiation. We find that Ste11 is only active in G(1) when Cdk activity is low. In the remaining part of the cell cycle, Ste11 becomes Cdk-phosphorylated at Thr 82 (T82), which inhibits its DNA-binding activity. Since the ste11 gene is autoregulated and the Ste11 protein is highly unstable, this Cdk switch rapidly extinguishes Ste11 activity when cells enter S phase. When we mutated T82 to aspartic acid, mimicking constant phosphorylation, cells no longer underwent differentiation. Conversely, changing T82 to alanine rendered Ste11-controlled transcription constitutive through the cell cycle, and allowed mating from S phase with increased frequency. Thus, Cdk phosphorylation mediates periodic expression of Ste11 and its target genes, and we suggest this to be part of the mechanism restricting differentiation to G(1).
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Affiliation(s)
- Søren Kjærulff
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Nicoline Resen Andersen
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Mia Trolle Borup
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Olaf Nielsen
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
- Corresponding author.E-MAIL ; FAX 45-35322113
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13
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Genomewide identification of pheromone-targeted transcription in fission yeast. BMC Genomics 2006; 7:303. [PMID: 17137508 PMCID: PMC1693924 DOI: 10.1186/1471-2164-7-303] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 11/30/2006] [Indexed: 11/16/2022] Open
Abstract
Background Fission yeast cells undergo sexual differentiation in response to nitrogen starvation. In this process haploid M and P cells first mate to form diploid zygotes, which then enter meiosis and sporulate. Prior to mating, M and P cells communicate with diffusible mating pheromones that activate a signal transduction pathway in the opposite cell type. The pheromone signalling orchestrates mating and is also required for entry into meiosis. Results Here we use DNA microarrays to identify genes that are induced by M-factor in P cells and by P-factor in M-cells. The use of a cyr1 genetic background allowed us to study pheromone signalling independently of nitrogen starvation. We identified a total of 163 genes that were consistently induced more than two-fold by pheromone stimulation. Gene disruption experiments demonstrated the involvement of newly discovered pheromone-induced genes in the differentiation process. We have mapped Gene Ontology (GO) categories specifically associated with pheromone induction. A direct comparison of the M- and P-factor induced expression pattern allowed us to identify cell-type specific transcripts, including three new M-specific genes and one new P-specific gene. Conclusion We found that the pheromone response was very similar in M and P cells. Surprisingly, pheromone control extended to genes fulfilling their function well beyond the point of entry into meiosis, including numerous genes required for meiotic recombination. Our results suggest that the Ste11 transcription factor is responsible for the majority of pheromone-induced transcription. Finally, most cell-type specific genes now appear to be identified in fission yeast.
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Kjaerulff S, Lautrup-Larsen I, Truelsen S, Pedersen M, Nielsen O. Constitutive activation of the fission yeast pheromone-responsive pathway induces ectopic meiosis and reveals ste11 as a mitogen-activated protein kinase target. Mol Cell Biol 2005; 25:2045-59. [PMID: 15713656 PMCID: PMC549357 DOI: 10.1128/mcb.25.5.2045-2059.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, meiosis normally takes place in diploid zygotes resulting from conjugation of haploid cells. In the present study, we report that the expression of a constitutively activated version of the pheromone-responsive mitogen-activated protein kinase kinase kinase (MAP3K) Byr2 can induce ectopic meiosis directly in haploid cells. We find that the Ste11 transcription factor becomes constitutively expressed in these cells and that the expression of pheromone-responsive genes no longer depends on nitrogen starvation. Epistasis analysis revealed that these conditions bypassed the requirement for the meiotic activator Mei3. Since Mei3 is normally needed for inactivation of the meiosis-repressing protein kinase Pat1, this finding suggests that the strong Byr2 signal causes inactivation of Pat1 by an alternative mechanism. Consistent with this possibility, we found that haploid meiosis was dramatically reduced when Ste11 was mutated to mimic phosphorylation by Pat1. The mutation of two putative MAPK sites in Ste11 also dramatically reduced the level of haploid meiosis, suggesting that Ste11 is a direct target of Spk1. Supporting this, we show that Spk1 can interact physically with Ste11 and also phosphorylate the transcription factor in vitro. Finally, we demonstrate that ste11 is required for pheromone-induced G1 arrest. Interestingly, when we mutated Ste11 in the sites for Pat1 and Spk1 phosphorylation simultaneously, the cells could still arrest in G1 in response to pheromone, suggesting the existence of yet a third bifurcation of the signaling pathway.
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Affiliation(s)
- Søren Kjaerulff
- Institute of Molecular Biology, University of Copenhagen, Øster Farimagsgade 2A, DK-1353 Copenhagen K, Denmark
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Petersen J, Nielsen O, Egel R, Hagan IM. FH3, a domain found in formins, targets the fission yeast formin Fus1 to the projection tip during conjugation. J Biophys Biochem Cytol 1998; 141:1217-28. [PMID: 9606213 PMCID: PMC2137179 DOI: 10.1083/jcb.141.5.1217] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Formins are involved in diverse aspects of morphogenesis, and share two regions of homology: FH1 and FH2. We describe a new formin homology region, FH3. FH3 is an amino-terminal domain that differs from the Rho binding site identified in Bni1p and p140mDia. The Schizosaccharomyces pombe formin Fus1 is required for conjugation, and is localized to the projection tip in cells of mating pairs. We replaced genomic fus1+ with green fluorescent protein (GFP)- tagged versions that lacked either the FH1, FH2, or FH3 domain. Deletion of any FH domain essentially abolished mating. FH3, but neither FH1 nor FH2, was required for Fus1 localization. An FH3 domain-GFP fusion protein localized to the projection tips of mating pairs. Thus, the FH3 domain alone can direct protein localization. The FH3 domains of both Fus1 and the S. pombe cytokinesis formin Cdc12 were able to localize GFP to the spindle pole body in half of the late G2 cells in a vegetatively growing population. Expression of both FH3-GFP fusions also affected cytokinesis. Overexpression of the spindle pole body component Sad1 altered the distribution of both Sad1 and the FH3-GFP domain. Together these data suggest that proteins at multiple sites can interact with FH3 domains.
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Affiliation(s)
- J Petersen
- Department of Genetics, Institute of Molecular Biology, OsterFarimagsgade 2A, University of Copenhagen, DK-1353 Copenhagen K, Denmark.
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16
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Banuett F. Signalling in the yeasts: an informational cascade with links to the filamentous fungi. Microbiol Mol Biol Rev 1998; 62:249-74. [PMID: 9618441 PMCID: PMC98914 DOI: 10.1128/mmbr.62.2.249-274.1998] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
All cells, from bacteria and yeasts to mammalian cells, respond to cues from their environment. A variety of mechanisms exist for the transduction of these external signals to the interior of the cell, resulting in altered patterns of protein activity. Eukaryotic cells commonly transduce external cues via a conserved module composed of three protein kinases, the mitogen-activated protein kinase (MAPK) cascade. This module can then activate substrates, some of which include transcriptional activators. Multiple MAPK signalling pathways coexist in a cell. This review considers different MAPK cascade signalling pathways that govern several aspects of the life cycle of budding and fission yeasts: conjugation and meiosis by the pheromone response pathway, stress response by the high-osmolarity sensing pathway, cell wall biosynthesis in response to activation of the low-osmolarity and heat-sensing pathway, and pseudohyphal growth in response to activation of a subset of the components of the pheromone response pathway. Because the MAPK cascade components are highly conserved, a key question in studies of these pathways is the mechanism by which specificity of response is achieved. Several other issues to be addressed in this review concern the nature of the receptors used to sense the external signals and the mechanism by which the receptors communicate with other components leading to activation of the MAPK cascade. Recently, it has become apparent that MAPK cascades are important in governing the pathogenicity of filamentous fungi.
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Affiliation(s)
- F Banuett
- Department of Biochemistry and Biophysics, School of Medicine, University of California, San Francisco, California 94143-0448, USA.
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17
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Kjaerulff S, Dooijes D, Clevers H, Nielsen O. Cell differentiation by interaction of two HMG-box proteins: Mat1-Mc activates M cell-specific genes in S.pombe by recruiting the ubiquitous transcription factor Ste11 to weak binding sites. EMBO J 1997; 16:4021-33. [PMID: 9233811 PMCID: PMC1170025 DOI: 10.1093/emboj/16.13.4021] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The Schizosaccharomyces pombe mfm1 gene is expressed in an M cell-specific fashion. This regulation requires two HMG-box proteins: the ubiquitous Ste11 transcription factor and the M cell-controlling protein Mat1-Mc. Here we report that the mfm1 promoter contains a single, weak Stell-binding site (a so-called TR-box) that can confer M-specificity on a heterologous promoter when present in eight copies. In vitro, both Mat1-Mc and Ste11 can bind this box with approximately the same affinity. The Mat1-Mc protein caused a dramatic increase in the DNA-binding of Ste11 to this box, under conditions where we could not detect Mat1-Mc in the resulting protein-DNA complex. When we changed a single base in the mfm1 TR-box, such that it resembled those boxes found in ubiquitously expressed genes, Ste11 binding was enhanced, and in vivo the mfm1 gene also became expressed in P cells where Mat1-Mc is absent. These findings suggest that M-specificity results from Mat1-Mc-mediated Ste11 binding to weak TR-boxes. We have also defined a novel motif (termed M-box), adjacent to the mfm1 TR-box, to which Mat1-Mc binds strongly. A DNA fragment containing both the TR- and the M-box allowed the formation of a complex containing both Ste11 and Mat1-Mc. A single copy of this fragment was sufficient to activate a heterologous promoter in an M-specific fashion, suggesting that these two boxes act in a synergistic manner.
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Affiliation(s)
- S Kjaerulff
- Department of Genetics, Institute of Molecular Biology, University of Copenhagen, Copenhagen K, Denmark
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18
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Imai Y, Davey J, Kawagishi-Kobayashi M, Yamamoto M. Genes encoding farnesyl cysteine carboxyl methyltransferase in Schizosaccharomyces pombe and Xenopus laevis. Mol Cell Biol 1997; 17:1543-51. [PMID: 9032282 PMCID: PMC231880 DOI: 10.1128/mcb.17.3.1543] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The mam4 mutation of Schizosaccharomyces pombe causes mating deficiency in h- cells but not in h+ cells. h- cells defective in mam4 do not secrete active mating pheromone M-factor. We cloned mam4 by complementation. The mam4 gene encodes a protein of 236 amino acids, with several potential membrane-spanning domains, which is 44% identical with farnesyl cysteine carboxyl methyltransferase encoded by STE14 and required for the modification of a-factor in Saccharomyces cerevisiae. Analysis of membrane fractions revealed that mam4 is responsible for the methyltransferase activity in S. pombe. Cells defective in mam4 produced farnesylated but unmethylated cysteine and small peptides but no intact M-factor. These observations strongly suggest that the mam4 gene product is farnesyl cysteine carboxyl methyltransferase that modifies M-factor. Furthermore, transcomplementation of S. pombe mam4 allowed us to isolate an apparent homolog of mam4 from Xenopus laevis (Xmam4). In addition to its sequence similarity to S. pombe mam4, the product of Xmam4 was shown to have a farnesyl cysteine carboxyl methyltransferase activity in S. pombe cells. The isolation of a vertebrate gene encoding farnesyl cysteine carboxyl methyltransferase opens the way to in-depth studies of the role of methylation in a large body of proteins, including Ras superfamily proteins.
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Affiliation(s)
- Y Imai
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan
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19
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Yabana N, Yamamoto M. Schizosaccharomyces pombe map1+ encodes a MADS-box-family protein required for cell-type-specific gene expression. Mol Cell Biol 1996; 16:3420-8. [PMID: 8668157 PMCID: PMC231336 DOI: 10.1128/mcb.16.7.3420] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We cloned the Schizosaccharomyces pombe map1 gene by virtue of its ability to stimulate transcription of the sxa2 gene, which encodes a carboxypeptidase expressed specifically in h- cells in response to mating-pheromone signaling. The cloned gene had a coding capacity of 398 amino acids split by two introns, and the deduced product was a protein of the MADS box family. This gene was most similar to Saccharomyces cerevisiae MCM1, which regulates cell-type-specific gene expression in budding yeast cells. Disruption of the S. pombe gene did not affect vegetative cell growth but conferred sterility. It blocked the mating ability of h+ cells completely and that of h- cells partially. Genetic and sequencing analysis indicated that the cloned gene is map1], which was originally defined by a mutation that caused h+-speciftic sterility. Northern (RNA) blot analysis showed that the function of map1 is absolutely essential for the expression of h+-specific genes and is required for the full activation of h--specific gene expression. Overexpression of map1 resulted in enhanced transcription of cell-type-specilic genes, but the range of genes affected by Map1 was restricted by the mating type of the cell. Results of yeast two-hybrid analysis suggested that Map1 may physically interact with Mat1-Pc, the product of the h(+)-specific mating-type gene mat1-Pc. On the basis of these observations, we speculate that Map1 may be a transcriptional regulator of cell-type-specific genes similar to S. cerevisiae MCM1, whose activity is modulated by the oil and alpha2 mating-type gene products.
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Affiliation(s)
- N Yabana
- Department of Biophysics and Biochemistry, School of Science, University of Tokyo, Hongo, Japan
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20
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Willer M, Hoffmann L, Styrkársdóttir U, Egel R, Davey J, Nielsen O. Two-step activation of meiosis by the mat1 locus in Schizosaccharomyces pombe. Mol Cell Biol 1995; 15:4964-70. [PMID: 7651414 PMCID: PMC230743 DOI: 10.1128/mcb.15.9.4964] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The mat1 locus is a key regulator of both conjugation and meiosis in the fission yeast Schizosaccharomyces pombe. Two alternative DNA segments of this locus, mat1-P and mat1-M, specify the haploid cell types (Plus and Minus). Each segment includes two genes: mat1-P includes mat1-Pc and mat1-Pm, while mat1-M includes mat1-Mc and mat1-Mm. The mat1-Pc and mat1-Mc genes are responsible for establishing the pheromone communication system that mediates conjugation between P and M cells, while all four mat1 genes are required for meiosis in diploid P/M cells. Our understanding of the initiation of meiosis is based largely on indirect observations, and a more precise investigation of these events was required to define the interaction between the mat1 genes. Here we resolve this issue using synthetic pheromones and P/M strains with mutations in either mat1-Pc or mat1-Mc. Our results suggest a model in which the mat1 locus plays two roles in controlling meiosis. In the first instance, the mat1-Pc and mat1-Mc functions are required to produce the mating pheromones and receptors that allow the generation of a pheromone signal. This signal is required to induce the expression of mat1-Pm and mat1-Mm. This appears to be the major pheromone-dependent step in controlling meiosis since ectopic expression of these genes allows meiosis in the absence of mat1-Pc and mat1-Mc. The mat1-Pm and mat1-Mm products complete the initiation of meiosis by activating transcription of the mei3 gene.
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Affiliation(s)
- M Willer
- Department of Genetics, University of Copenhagen, Denmark
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21
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Petersen J, Weilguny D, Egel R, Nielsen O. Characterization of fus1 of Schizosaccharomyces pombe: a developmentally controlled function needed for conjugation. Mol Cell Biol 1995; 15:3697-707. [PMID: 7791776 PMCID: PMC230607 DOI: 10.1128/mcb.15.7.3697] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In Schizosaccharomyces pombe, the fus1 mutation blocks conjugation at a point after cell contact and agglutination. The cell walls separating the mating partners are not degraded, which prevents cytoplasmic fusion. In order to investigate the molecular mechanism of conjugation, we cloned the fus1 gene and found that it is capable of encoding a 1,372-amino-acid protein with no significant similarities to other known proteins. Expression of the fus1 gene is regulated by the developmental state of the cells. Transcription is induced by nitrogen starvation and requires a pheromone signal in both P and M cell types. Consequently, mutants defective in the pheromone response pathway fail to induce fus1 expression. The ste11 gene, which encodes a transcription factor controlling expression of many genes involved in sexual differentiation, is also required for transcription of fus1. Furthermore, deletion of two potential Ste11 recognition sites in the fus1 promoter region abolished transcription, and expression could be restored when we inserted a different Ste11 site from the mat1-P promoter. Since this element was inverted relative to the fus1 element, we conclude that activation of transcription by Ste11 is independent of orientation. Although the fus1 mutant has a phenotype very similar to that of Saccharomyces cerevisiae fus1 mutants, the two proteins appear to have different roles in the process of cell fusion. Budding yeast Fus1 is a typical membrane protein and contains an SH3 domain. Fission yeast Fus1 has no features of a membrane protein, yet it appears to localize to the projection tip. A characteristic proline-rich potential SH3 binding site may mediate interaction with other proteins.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Blotting, Northern
- Blotting, Western
- Cloning, Molecular
- Conjugation, Genetic/genetics
- DNA Mutational Analysis
- Fluorescent Antibody Technique
- Fungal Proteins/genetics
- Fungal Proteins/isolation & purification
- Gene Expression Regulation, Fungal
- Genes, Fungal/genetics
- Genes, src/genetics
- Genetic Complementation Test
- Membrane Proteins
- Molecular Sequence Data
- Mutation
- Pheromones/pharmacology
- Promoter Regions, Genetic/genetics
- Restriction Mapping
- Saccharomyces cerevisiae Proteins
- Schizosaccharomyces/drug effects
- Schizosaccharomyces/genetics
- Schizosaccharomyces pombe Proteins
- Sequence Analysis, DNA
- Sequence Deletion
- Sequence Homology, Amino Acid
- Signal Transduction/genetics
- Transcription Factors/genetics
- Transcription, Genetic
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Affiliation(s)
- J Petersen
- Department of Genetics, University of Copenhagen, Denmark
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