Journal articles on the topic 'Mating a-factor'
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1
Hirschhorn, J. N., and F. Winston. "SPT3 is required for normal levels of a-factor and alpha-factor expression in Saccharomyces cerevisiae." Molecular and Cellular Biology 8, no. 2 (February 1988): 822–27. http://dx.doi.org/10.1128/mcb.8.2.822-827.1988.
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Mutations in the Saccharomyces cerevisiae SPT3 gene were previously found to cause suppression of Ty and delta insertion mutations in 5'-noncoding regions of genes. This suppression likely results from the fact that SPT3 is required for transcription initiation in delta sequences. Other additional phenotypes of spt3 mutants, including a mating defect, suggest that SPT3 is required for normal levels of expression of other genes. We analyzed the mating defect in spt3 mutants and showed that the levels of transcripts of the three major mating pheromone genes, MF alpha 1, MFa1, MFa2, were all reduced. The reduction in expression of these genes in spt3 mutants was not due to expression of a silent mating type cassette. Furthermore, we showed that the spt3 mating defect was manifest at the levels of both cellular fusion and nuclear fusion.
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Hirschhorn, J. N., and F. Winston. "SPT3 is required for normal levels of a-factor and alpha-factor expression in Saccharomyces cerevisiae." Molecular and Cellular Biology 8, no. 2 (February 1988): 822–27. http://dx.doi.org/10.1128/mcb.8.2.822.
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Mutations in the Saccharomyces cerevisiae SPT3 gene were previously found to cause suppression of Ty and delta insertion mutations in 5'-noncoding regions of genes. This suppression likely results from the fact that SPT3 is required for transcription initiation in delta sequences. Other additional phenotypes of spt3 mutants, including a mating defect, suggest that SPT3 is required for normal levels of expression of other genes. We analyzed the mating defect in spt3 mutants and showed that the levels of transcripts of the three major mating pheromone genes, MF alpha 1, MFa1, MFa2, were all reduced. The reduction in expression of these genes in spt3 mutants was not due to expression of a silent mating type cassette. Furthermore, we showed that the spt3 mating defect was manifest at the levels of both cellular fusion and nuclear fusion.
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Michaelis, S., and I. Herskowitz. "The a-factor pheromone of Saccharomyces cerevisiae is essential for mating." Molecular and Cellular Biology 8, no. 3 (March 1988): 1309–18. http://dx.doi.org/10.1128/mcb.8.3.1309-1318.1988.
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The Saccharomyces cerevisiae pheromone a-factor is produced by a cells and interacts with alpha cells to cause cell cycle arrest and other physiological responses associated with mating. Two a-factor structural genes, MFA1 and MFA2, have been previously cloned with synthetic probes based on the a-factor amino acid sequence (A. Brake, C. Brenner, R. Najarian, P. Laybourn, and J. Merryweather, cited in M.-J. Gething [ed.], Protein transport and secretion, 1985). We have examined the function of these genes in a-factor production and mating by construction and analysis of chromosomal null mutations. mfa1 and mfa2 single mutants each exhibited approximately half the wild-type level of a-factor activity and were proficient in mating, whereas the mfa1 mfa2 double mutant produced no a-factor and was unable to mate. These results demonstrate that both genes are functional, that each gene makes an equivalent contribution to the a-factor activity and mating capacity of a cells, and that a-factor plays an essential role in mating. Strikingly, exogenous a-factor did not alleviate the mating defect of the double mutant, suggesting that an a cell must be producing a-factor to be an effective mating partner.
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Michaelis, S., and I. Herskowitz. "The a-factor pheromone of Saccharomyces cerevisiae is essential for mating." Molecular and Cellular Biology 8, no. 3 (March 1988): 1309–18. http://dx.doi.org/10.1128/mcb.8.3.1309.
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The Saccharomyces cerevisiae pheromone a-factor is produced by a cells and interacts with alpha cells to cause cell cycle arrest and other physiological responses associated with mating. Two a-factor structural genes, MFA1 and MFA2, have been previously cloned with synthetic probes based on the a-factor amino acid sequence (A. Brake, C. Brenner, R. Najarian, P. Laybourn, and J. Merryweather, cited in M.-J. Gething [ed.], Protein transport and secretion, 1985). We have examined the function of these genes in a-factor production and mating by construction and analysis of chromosomal null mutations. mfa1 and mfa2 single mutants each exhibited approximately half the wild-type level of a-factor activity and were proficient in mating, whereas the mfa1 mfa2 double mutant produced no a-factor and was unable to mate. These results demonstrate that both genes are functional, that each gene makes an equivalent contribution to the a-factor activity and mating capacity of a cells, and that a-factor plays an essential role in mating. Strikingly, exogenous a-factor did not alleviate the mating defect of the double mutant, suggesting that an a cell must be producing a-factor to be an effective mating partner.
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Brizzio, V., A. E. Gammie, G. Nijbroek, S. Michaelis, and M. D. Rose. "Cell fusion during yeast mating requires high levels of a-factor mating pheromone." Journal of Cell Biology 135, no. 6 (December 15, 1996): 1727–39. http://dx.doi.org/10.1083/jcb.135.6.1727.
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During conjugation, two yeast cells fuse to form a single zygote. Cell fusion requires extensive remodeling of the cell wall, both to form a seal between the two cells and to remove the intervening material. The two plasma membranes then fuse to produce a continuous cytoplasm. We report the characterization of two cell fusion defective (Fus-) mutants, fus5 and fus8, isolated previously in our laboratory. Fluorescence and electron microscopy demonstrated that the fus5 and fus8 mutant zygotes were defective for cell wall remodeling/removal but not plasma membrane fusion. Strikingly, fus5 and fus8 were a specific; both mutations caused the mutant phenotype when present in the MATa parent but not in the MAT alpha parent. Consistent with an a-specific defect, the fus5 and fus8 mutants produced less a-factor than the isogenic wild-type strain. FUS5 and FUS8 were determined to be allelic to AXL1 and RAM1, respectively, two genes known to be required for biogenesis of a-factor. Several experiments demonstrated that the partial defect in a-factor production resulted in the Fus- phenotype. First, overexpression of a-factor in the fus mutants suppressed the Fus- defect. Second, matings to an MAT alpha partner supersensitive to mating pheromone (sst2 delta) suppressed the Fus- defect in trans. Finally, the gene encoding a-factor, MFA1, was placed under the control of a repressible promoter; reduced levels of wild-type a-factor caused an identical cell fusion defect during mating. We conclude that high levels of pheromone are required as one component of the signal for prezygotes to initiate cell fusion.
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Tanaka, Ayako, Kazuhiro Miyazaki, Haruki Murakami, and Susumu Shiraishi. "Sequence characterized amplified region markers tightly linked to the mating factors ofLentinula edodes." Genome 47, no. 1 (January 1, 2004): 156–62. http://dx.doi.org/10.1139/g03-131.
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Detecting the mating types in shiitake, Lentinula edodes (Berk.) Pegler, is important for making progress in the breeding of this mushroom and determining the compatibility of the pair to cross. Shiitake is a tetrapolar fungus with two unlinking mating factors, A factor and B factor. We screened molecular markers linked to the mating factors using the randomly amplified polymorphic DNA (RAPD) method to develop the mating type identification procedure. Using 147 oligonucleotide primers, a total of 6 linkage markers for the shiitake mating factors, 4 markers for the A factor and 2 markers for the B factor, were discovered with a logarithm of the odds threshold of 3.0 for linkage. Two RAPDs that perfectly segregated with each mating factor among 72 basidiospore strains were detected. Both of these RAPDs were cloned and sequenced to convert them to the sequence characterized amplified region (SCAR) markers. Four primers, two sets of primers, were designed according to the internal sequences of two RAPDs tightly linking to the A factor or B factor. Consequently, we determined the polymerase chain reaction condition for multiplex analyses of these SCAR markers.Key words: Lentinula edodes, SCAR, diagnostic, mating type.
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Davey, J. "M-factor, a farnesylated mating factor from the fission yeast Schizosaccharomyces pombe." Biochemical Society Transactions 24, no. 3 (August 1, 1996): 718–23. http://dx.doi.org/10.1042/bst0240718.
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Chen, Peng, Stephanie K. Sapperstein, Jonathan D. Choi, and Susan Michaelis. "Biogenesis of the Saccharomyces cerevisiae Mating Pheromone a-Factor." Journal of Cell Biology 136, no. 2 (January 27, 1997): 251–69. http://dx.doi.org/10.1083/jcb.136.2.251.
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The Saccharomyces cerevisiae mating pheromone a-factor is a prenylated and carboxyl methylated extracellular peptide signaling molecule. Biogenesis of the a-factor precursor proceeds via a distinctive multistep pathway that involves COOH-terminal modification, NH2-terminal proteolysis, and a nonclassical export mechanism. In this study, we examine the formation and fate of a-factor biosynthetic intermediates to more precisely define the events that occur during a-factor biogenesis. We have identified four distinct a-factor biosynthetic intermediates (P0, P1, P2, and M) by metabolic labeling, immunoprecipitation, and SDSPAGE. We determined the biochemical composition of each by defining their NH2-terminal amino acid and COOH-terminal modification status. Unexpectedly, we discovered that not one, but two NH2-terminal cleavage steps occur during the biogenesis of a-factor. In addition, we have shown that COOH-terminal prenylation is required for the NH2-terminal processing of a-factor and that all the prenylated a-factor intermediates (P1, P2, and M) are membrane bound, suggesting that many steps of a-factor biogenesis occur in association with membranes. We also observed that although the biogenesis of a-factor is a rapid process, it is inherently inefficient, perhaps reflecting the potential for regulation. Previous studies have identified gene products that participate in the COOH-terminal modification (Ram1p, Ram2p, Ste14p), NH2-terminal processing (Ste24p, Axl1p), and export (Ste6p) of a-factor. The intermediates defined in the present study are discussed in the context of these biogenesis components to formulate an overall model for the pathway of a-factor biogenesis.
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Hughes, D. A., N. Yabana, and M. Yamamoto. "Transcriptional regulation of a Ras nucleotide-exchange factor gene by extracellular signals in fission yeast." Journal of Cell Science 107, no. 12 (December 1, 1994): 3635–42. http://dx.doi.org/10.1242/jcs.107.12.3635.
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The ste6 gene of Schizosaccharomyces pombe encodes a putative GDP-GTP exchange factor for the ras1 gene product. Genetic analysis of the ste6 and ras1 genes has shown that they are required for mating and for the response to mating pheromones. In this study we show that expression of the ste6-encoded mRNA is induced by nitrogen starvation, the physiological signal that triggers mating and sexual differentiation. Exposure to mating pheromones enhances the induction of ste6 expression upon nitrogen starvation. Pheromone-induced expression requires not only the function of components of the pheromone-signalling pathway, but also ras1 function. Furthermore, mutants in which the Ras1 protein is activated have higher basal and induced levels of ste6 gene expression than wild-type cells. These observations indicate the existence of a positive-feedback loop through which Ras1 stimulates the expression of its own activator. Since Ste6 is likely to promote the exchange of guanine nucleotides on Ras1 protein, our results suggest an important role for GDP-GTP exchange in the regulation of Ras1 activity during the mating process in S. pombe.
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Xue, Chu-Biao, Guy A. Caldwell, Jeffrey M. Becker, and Fred Naider. "Total synthesis of the lipopeptide a-mating factor ofSaccharomyces cerevisiae." Biochemical and Biophysical Research Communications 162, no. 1 (July 1989): 253–57. http://dx.doi.org/10.1016/0006-291x(89)91989-x.
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Kurjan, J. "Alpha-factor structural gene mutations in Saccharomyces cerevisiae: effects on alpha-factor production and mating." Molecular and Cellular Biology 5, no. 4 (April 1985): 787–96. http://dx.doi.org/10.1128/mcb.5.4.787-796.1985.
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The role of alpha-factor structural genes MF alpha 1 and MF alpha 2 in alpha-factor production and mating has been investigated by the construction of mf alpha 1 and mf alpha 2 mutations that totally eliminate gene function. An mf alpha 1 mutant in which the entire coding region is deleted shows a considerable decrease in alpha-factor production and a 75% decrease in mating. Mutations in mf alpha 2 have little or no effect on alpha-factor production or mating. The mf alpha 1 mf alpha 2 double mutants are completely defective in mating and alpha-factor production. These results indicate that at least one alpha-factor structural gene product is required for mating in MAT alpha cells, that MF alpha 1 is responsible for the majority of alpha-factor production, and that MF alpha 1 and MF alpha 2 are the only active alpha-factor genes.
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Kurjan, J. "Alpha-factor structural gene mutations in Saccharomyces cerevisiae: effects on alpha-factor production and mating." Molecular and Cellular Biology 5, no. 4 (April 1985): 787–96. http://dx.doi.org/10.1128/mcb.5.4.787.
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The role of alpha-factor structural genes MF alpha 1 and MF alpha 2 in alpha-factor production and mating has been investigated by the construction of mf alpha 1 and mf alpha 2 mutations that totally eliminate gene function. An mf alpha 1 mutant in which the entire coding region is deleted shows a considerable decrease in alpha-factor production and a 75% decrease in mating. Mutations in mf alpha 2 have little or no effect on alpha-factor production or mating. The mf alpha 1 mf alpha 2 double mutants are completely defective in mating and alpha-factor production. These results indicate that at least one alpha-factor structural gene product is required for mating in MAT alpha cells, that MF alpha 1 is responsible for the majority of alpha-factor production, and that MF alpha 1 and MF alpha 2 are the only active alpha-factor genes.
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Marcus, S., C. B. Xue, F. Naider, and J. M. Becker. "Degradation of a-factor by a Saccharomyces cerevisiae alpha-mating-type-specific endopeptidase: evidence for a role in recovery of cells from G1 arrest." Molecular and Cellular Biology 11, no. 2 (February 1991): 1030–39. http://dx.doi.org/10.1128/mcb.11.2.1030-1039.1991.
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Mating response between opposite mating types of Saccharomyces cerevisiae is dependent upon alpha factor, a tridecapeptide, and a-factor, an isoprenylated, methyl esterified dodecapeptide whose interaction with the alpha target cell has not been characterized. We report on the first biochemical and physiological evidence of an alpha-mating-type-specific a-factor-degrading activity. Radioiodinated a-factor was used to identify the a-factor-degrading activity, which is cell associated, endoproteolytic, and not required for response to pheromone. a-factor degradation was not energy dependent, nor did it require pheromone internalization or interaction with its receptor. Phenylmethylsulfonyl fluoride and tosyl-L-arginyl-methyl ester inhibited degradation of a-factor and increased the time required by alpha cells to recover from a-factor-induced growth arrest and morphological alteration, providing evidence that a-factor degradation plays a role in the recovery of alpha cells from the pheromone response.
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Marcus, S., C. B. Xue, F. Naider, and J. M. Becker. "Degradation of a-factor by a Saccharomyces cerevisiae alpha-mating-type-specific endopeptidase: evidence for a role in recovery of cells from G1 arrest." Molecular and Cellular Biology 11, no. 2 (February 1991): 1030–39. http://dx.doi.org/10.1128/mcb.11.2.1030.
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Mating response between opposite mating types of Saccharomyces cerevisiae is dependent upon alpha factor, a tridecapeptide, and a-factor, an isoprenylated, methyl esterified dodecapeptide whose interaction with the alpha target cell has not been characterized. We report on the first biochemical and physiological evidence of an alpha-mating-type-specific a-factor-degrading activity. Radioiodinated a-factor was used to identify the a-factor-degrading activity, which is cell associated, endoproteolytic, and not required for response to pheromone. a-factor degradation was not energy dependent, nor did it require pheromone internalization or interaction with its receptor. Phenylmethylsulfonyl fluoride and tosyl-L-arginyl-methyl ester inhibited degradation of a-factor and increased the time required by alpha cells to recover from a-factor-induced growth arrest and morphological alteration, providing evidence that a-factor degradation plays a role in the recovery of alpha cells from the pheromone response.
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Caplan, S., and J. Kurjan. "Role of alpha-factor and the MF alpha 1 alpha-factor precursor in mating in yeast." Genetics 127, no. 2 (February 1, 1991): 299–307. http://dx.doi.org/10.1093/genetics/127.2.299.
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Abstract The peptide pheromones secreted by a and alpha cells (called a-factor and alpha-factor, respectively) are each encoded by two structural genes. For strains of either mating type, addition of exogenous pheromone does not alleviate the mating defect of mutants with disruptions of both structural genes. In addition, a particular insertion mutation in the major alpha-factor structural gene (MF alpha 1) that should result in an altered product inhibits alpha mating. These results suggested that the pheromone precursors (the MF alpha 1 pro region in particular) might play a second role in mating separate from the role of pheromone production. To analyze the role of alpha-factor and the MF alpha 1 precursor in alpha mating, we have constructed two classes of mutants. The mating defects of mutants that should produce the MF alpha 1 pro region peptide but no alpha-factor could not be alleviated by addition of exogenous alpha-factor in crosses to a wild-type a strain, indicating that the previous results were not due to an inability of the disruption mutants to produce the pro region peptide. Mutants able to produce alpha-factor, but with a variety of alterations in MF alpha 1 precursor structure, mated at levels proportional to the levels of alpha-factor produced, suggesting that the only role of the alpha-factor precursor in mating is to produce alpha-factor. Both of these results argue against a role for the MF alpha 1 pro region separate from its role in alpha-factor production.(ABSTRACT TRUNCATED AT 250 WORDS)
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Marcus, S., G. A. Caldwell, D. Miller, C. B. Xue, F. Naider, and J. M. Becker. "Significance of C-terminal cysteine modifications to the biological activity of the Saccharomyces cerevisiae a-factor mating pheromone." Molecular and Cellular Biology 11, no. 7 (July 1991): 3603–12. http://dx.doi.org/10.1128/mcb.11.7.3603-3612.1991.
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We have undertaken total synthesis of the Saccharomyces cerevisiae a-factor (NH2-YIIKGVFWDPAC[S-farnesyl]-COOCH3) and several Cys-12 analogs to determine the significance of S-farnesylation and carboxy-terminal methyl esterification to the biological activity of this lipopeptide mating pheromone. Replacement of either the farnesyl group or the carboxy-terminal methyl ester by a hydrogen atom resulted in marked reduction but not total loss of bioactivity as measured by a variety of assays. Moreover, both the farnesyl and methyl ester groups could be replaced by other substituents to produce biologically active analogs. The bioactivity of a-factor decreased as the number of prenyl units on the cysteine sulfur decreased from three to one, and an a-factor analog having the S-farnesyl group replaced by an S-hexadecanyl group was more active than an S-methyl a-factor analog. Thus, with two types of modifications, a-factor activity increased as the S-alkyl group became bulkier and more hydrophobic. MATa cells having deletions of the a-factor structural genes (mfal1 mfa2 mutants) were capable of mating with either sst2 or wild-type MAT alpha cells in the presence of exogenous a-factor, indicating that it is not absolutely essential for MATa cells to actively produce a-factor in order to mate. Various a-factor analogs were found to partially restore mating to these strains as well, and their relative activities in the mating restoration assay were similar to their activities in the other assays used in this study. Mating was not restored by addition of exogenous a-factor to a cross of a wild-type MAT alpha strain and a MATaste6 mutant, indicating a role of the STE6 gene product in mating in addition to its secretion of a-factor.
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Marcus, S., G. A. Caldwell, D. Miller, C. B. Xue, F. Naider, and J. M. Becker. "Significance of C-terminal cysteine modifications to the biological activity of the Saccharomyces cerevisiae a-factor mating pheromone." Molecular and Cellular Biology 11, no. 7 (July 1991): 3603–12. http://dx.doi.org/10.1128/mcb.11.7.3603.
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We have undertaken total synthesis of the Saccharomyces cerevisiae a-factor (NH2-YIIKGVFWDPAC[S-farnesyl]-COOCH3) and several Cys-12 analogs to determine the significance of S-farnesylation and carboxy-terminal methyl esterification to the biological activity of this lipopeptide mating pheromone. Replacement of either the farnesyl group or the carboxy-terminal methyl ester by a hydrogen atom resulted in marked reduction but not total loss of bioactivity as measured by a variety of assays. Moreover, both the farnesyl and methyl ester groups could be replaced by other substituents to produce biologically active analogs. The bioactivity of a-factor decreased as the number of prenyl units on the cysteine sulfur decreased from three to one, and an a-factor analog having the S-farnesyl group replaced by an S-hexadecanyl group was more active than an S-methyl a-factor analog. Thus, with two types of modifications, a-factor activity increased as the S-alkyl group became bulkier and more hydrophobic. MATa cells having deletions of the a-factor structural genes (mfal1 mfa2 mutants) were capable of mating with either sst2 or wild-type MAT alpha cells in the presence of exogenous a-factor, indicating that it is not absolutely essential for MATa cells to actively produce a-factor in order to mate. Various a-factor analogs were found to partially restore mating to these strains as well, and their relative activities in the mating restoration assay were similar to their activities in the other assays used in this study. Mating was not restored by addition of exogenous a-factor to a cross of a wild-type MAT alpha strain and a MATaste6 mutant, indicating a role of the STE6 gene product in mating in addition to its secretion of a-factor.
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Mu, Xiaokai, Bo Yuan, Yunlong Wang, Qingchao Sun, Chao Zhang, Wei Sun, and Chong Liu. "A New Application of Taguchi Method: Matching and Optimization of Assembly Deviation of Mechanical System." Journal of Physics: Conference Series 2029, no. 1 (September 1, 2021): 012141. http://dx.doi.org/10.1088/1742-6596/2029/1/012141.
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Abstract In order to achieve high assembly accuracy on the basis of low manufacturing accuracy and low cost, a method of deviation factor matching and optimization based on Taguchi theory is proposed. Firstly, the specific process of multi factor matching and optimization is given based on Taguchi theory. Secondly, the orthogonal experiments were set from the aspects of performance index, influencing factors determination, orthogonal table selection and so on, and the best level combination of each deviation was selected to form the factor matching and optimization experiment scheme based on Taguchi method. Finally, taking the horizontal machining center as the object, the Taguchi method is used to match the deviation factors of each mating surface, and the best parameter combination of control factors is A1B2C2D1E1, which verifies the effectiveness and practicability of Taguchi method. The research method in this study provides a strong support for the realization of high assembly accuracy and performance without increasing cost.
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Boivin, Guy. "Sperm as a limiting factor in mating success in Hymenoptera parasitoids." Entomologia Experimentalis et Applicata 146, no. 1 (July 19, 2012): 149–55. http://dx.doi.org/10.1111/j.1570-7458.2012.01291.x.
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Betz, R., J. W. Crabb, H. E. Meyer, R. Wittig, and W. Duntze. "Amino acid sequences of a-factor mating peptides from Saccharomyces cerevisiae." Journal of Biological Chemistry 262, no. 2 (January 1987): 546–48. http://dx.doi.org/10.1016/s0021-9258(19)75817-7.
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Sengupta, P., and B. H. Cochran. "MAT alpha 1 can mediate gene activation by a-mating factor." Genes & Development 5, no. 10 (October 1, 1991): 1924–34. http://dx.doi.org/10.1101/gad.5.10.1924.
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Davey, John. "Isolation and quantitation of M-factor, a diffusible mating factor from the fission yeastSchizosaccharomyces pombe." Yeast 7, no. 4 (May 1991): 357–66. http://dx.doi.org/10.1002/yea.320070406.
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Elia, L., and L. Marsh. "Role of the ABC transporter Ste6 in cell fusion during yeast conjugation." Journal of Cell Biology 135, no. 3 (November 1, 1996): 741–51. http://dx.doi.org/10.1083/jcb.135.3.741.
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Though early stages of yeast conjugation are well-mimicked by treatment with pheromones, the final degradation of the cell wall and membrane fusion of mating that leads to cytoplasmic mixing may require separate signals. Mutations that blocked cell fusion during mating in Saccharomyces cerevisiae were identified in a multipartite screen. The three tightest mutations proved to be partial-function alleles of the ABC-transporter gene STE6 required for transport of a-factor. The ste6(cefl-1) allele was recovered and sequenced. The ste6(cefl-1) allele contained a stop codon predicted to truncate Ste6 at amino acid residue 862 (of 1290). The ste6(cef) mutations reduced, but did not eliminate, expression of a-factor. Light and electron microscopy revealed that unlike ste6 null mutations which block mating before the formation of mating pairs, the ste6(cef) (cell fusion) alleles permitted early steps in mating to proceed normally but blocked at a late stage in conjugation where mating partners were encased by a single cell wall and separated by only a thin layer of cell wall material we term the fusion wall. Morphologically the prezygotes appeared symmetrical with successful cell wall fusion at the periphery of the region of cell contact. Responses to a-factor were efficiently induced in partner cells under mating conditions as expected given the symmetric appearance of the prezygotes. A strain expressing a ste6(K1093A) mutation that conferred export of a twofold to fourfold higher level of a-factor than ste6(cef) did not accumulate prezygotes during mating which could indicate a tight threshold of a-factor signaling required for mating. However, mating to an sst2 partner which has a greatly increased sensitivity to a-factor did not suppress the fusion defect of a ste6(cef) strain. Overexpression of the structural gene for a-factor also did not suppress the fusion defect. It is possible that a-factor or STE6 play more complex roles in cell fusion.
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Brefort, Thomas, Philip Müller, and Regine Kahmann. "The High-Mobility-Group Domain Transcription Factor Rop1 Is a Direct Regulator of prf1 in Ustilago maydis." Eukaryotic Cell 4, no. 2 (February 2005): 379–91. http://dx.doi.org/10.1128/ec.4.2.379-391.2005.
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ABSTRACT In the smut fungus Ustilago maydis, the pheromone signal is transmitted via a mitogen-activated protein kinase module to the high-mobility-group (HMG) domain transcription factor Prf1, leading to its activation. This triggers sexual and pathogenic development since Prf1 binds to the PRE boxes located in the promoters of the a and b mating type genes. Here, we present the characterization of rop1 and hmg3, encoding two additional sequence-specific HMG domain proteins. While hmg3 mutants are slightly impaired in mating and do form conjugation hyphae, rop1 deletion strains display a severe mating and filamentation defect and do not respond to pheromone stimulation. In particular, rop1 is essential for pheromone-induced gene expression in axenic culture. Constitutive expression of prf1 fully complements the mating defect of rop1 mutants, indicating that rop1 is required for prf1 gene expression. Indeed, we could show that Rop1 binds directly to specific elements in the prf1 promoter. Surprisingly, on the plant surface, rop1 deletion strains do form conjugation hyphae and express sufficient amounts of prf1 to cause full pathogenicity. This indicates the involvement of additional components in the regulation of prf1 gene expression during pathogenic growth.
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Barale, Sophie, Derek McCusker, and Robert A. Arkowitz. "The Exchange Factor Cdc24 Is Required for Cell Fusion during Yeast Mating." Eukaryotic Cell 3, no. 4 (August 2004): 1049–61. http://dx.doi.org/10.1128/ec.3.4.1049-1061.2004.
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ABSTRACT During Saccharomyces cerevisiae mating, chemotropic growth and cell fusion are critical for zygote formation. Cdc24p, the guanine nucleotide exchange factor for the Cdc42 G protein, is necessary for oriented growth along a pheromone gradient during mating. To understand the functions of this critical Cdc42p activator, we identified additional cdc24 mating mutants. Two mating-specific mutants, the cdc24-m5 and cdc24-m6 mutants, each were isolated with a mutated residue in the conserved catalytic domain. The cdc24-m6 mutant responds normally to pheromone and orients its growth towards a mating partner yet accumulates prezygotes during mating. cdc24-m6 prezygotes have two apposed intact cell walls and do not correctly localize proteins required for cell fusion, despite normal exocytosis. Our results indicate that the exchange factor Cdc24p is necessary for maintaining or restricting specific proteins required for cell fusion to the cell contact region during mating.
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Sherwood, John E., Paula J. Kosted, Cynthia M. Anderson, and Shirley A. Gerhardt. "Production of a Mating Inhibitor by Ustilago hordei." Phytopathology® 88, no. 5 (May 1998): 456–64. http://dx.doi.org/10.1094/phyto.1998.88.5.456.
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Ustilago hordei, the cause of barley covered smut, was found to produce a factor that inhibited its own mating. The mating inhibition factor (MIF) specifically inhibited mating of U. hordei and other Ustilago spp., but not teliospore germination or sporidial growth. MIF did prevent teliospore germination of Tilletia caries and T. contraversa. MIF was found at low levels in culture supernatants of either mating type of U. hordei grown separately, but at higher levels when both mating types were grown together, in the supernatants of MAT-1 mating type cells transformed with the MAT-1 pheromone gene mfa1 and of MAT-2 cells transformed with either mfa1 or the MAT-1 pheromone receptor gene pra1. Diploid cells produced no detectable inhibitor, nor did MAT-1 cells with a disrupted mating type locus that deleted both mfa1 and pra1. MIF production was restored when mfa1, but not pra1, was added back to the MAT-1Δ cells. MIF activity was altered by protease treatment. Highly purified MIF from MAT-1 cells contained cysteine methyl ester, farnesyl cysteine, farnesyl cysteine methyl ester, and a dodecapeptide with a mass consistent with that of MAT-1 pheromone lacking the terminal cysteine. Since smut fungi must first mate to become pathogenic, mating inhibition has the potential to be an effective method of disease control for these pathogens.
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Telford, Steven R., and Miranda L. Dyson. "Some Determinants of the Mating System in a Population of Painted Reed Frogs (Hyperolius Marmoratus)." Behaviour 106, no. 3-4 (1988): 265–78. http://dx.doi.org/10.1163/156853988x00287.
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AbstractHyperolius marmoratus shares its breeding site with 12 synchronously breeding species. Males call from elevated perches to attract females. Observations of captive populations suggest that males may adopt alternative mating strategies when chorus densities are high. Similar strategies were not observed in natural choruses. The operational sex ratio (OSR) was always male-biased and also highly variable. Mating was polygynous, only 25% of the male population actually mated. Females mated either once or twice. Variance in mating success was much greater among males, an obvious consequence of a skewed OSR. Female choice was probably not a causal factor because male mating success was correlated with neither size nor age. Size-based variation in the male advertisement call does exist, but females cannot exploit this potential vocal cue because of their impaired discriminatory ability in a complex sonic environment and the potential risk of mismating. Although the mating system may best be described as lek-like, with males forming organised choruses through competitive interactions, the variance in male mating success is probably a consequence of stochastic factors.
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Hsueh, Yen-Ping, and Wei-Chiang Shen. "A Homolog of Ste6, the a-Factor Transporter in Saccharomyces cerevisiae, Is Required for Mating but Not for Monokaryotic Fruiting in Cryptococcus neoformans." Eukaryotic Cell 4, no. 1 (January 2005): 147–55. http://dx.doi.org/10.1128/ec.4.1.147-155.2005.
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ABSTRACT Fungal pheromones function during the initial recognition stage of the mating process. One type of peptide pheromone identified in ascomycetes and basidiomycetes terminates in a conserved CAAX motif and requires extensive posttranslational modifications to become mature and active. A well-studied representative is the a-factor of Saccharomyces cerevisiae. Unlike the typical secretory pathway utilized by most peptides, an alternative mechanism involving the ATP-binding cassette transporter Ste6 is used for the export of mature a-factor. Cryptococcus neoformans, a bipolar human pathogenic basidiomycete, produces CAAX motif-containing lipopeptide pheromones in both MAT a and MATα cells. Virulence studies with a congenic pair of C. neoformans serotype D strains have shown that MATα cells are more virulent than MAT a cells. Characterization of the MATα pheromones indicated that an autocrine signaling loop may contribute to the differentiation and virulence of MATα cells. To further address the role of pheromones in the signaling loop, we identified a STE6 homolog in the C. neoformans genome and determined its function by gene disruption. The ste6 mutants in either mating-type background showed partially impaired mating functions, and mating was completely abolished in a bilateral mutant cross. Surprisingly, the MATα ste6 mutant does not exhibit a defect in monokaryotic fruiting, suggesting that the activation of the autocrine signaling loop by the pheromone is via a Ste6-independent mechanism. MFα pheromone itself is essential for this process and could induce the signaling response intracellularly in MATα cells. Our data demonstrate that Ste6 is evolutionarily conserved for mating and is not required for monokaryotic fruiting in C. neoformans.
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Seike, Taisuke, Taro Nakamura, and Chikashi Shimoda. "Molecular coevolution of a sex pheromone and its receptor triggers reproductive isolation in Schizosaccharomyces pombe." Proceedings of the National Academy of Sciences 112, no. 14 (March 23, 2015): 4405–10. http://dx.doi.org/10.1073/pnas.1501661112.
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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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XUE, CHU-BIAO, ARIEL EWENSON, JEFFREY M. BECKER, and FRED NAIDER. "Solution phase synthesis of Saccharomyces cerevisiae a-mating factor and its analogs." International Journal of Peptide and Protein Research 36, no. 4 (January 12, 2009): 362–73. http://dx.doi.org/10.1111/j.1399-3011.1990.tb01295.x.
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Naider, Fred, John Gounarides, Chu-Biao Xue, Effimia Bargiota, and Jeffrey M. Becker. "Studies on the yeast ?-mating factor: A model for mammalian peptide hormones." Biopolymers 32, no. 4 (April 1992): 335–39. http://dx.doi.org/10.1002/bip.360320407.
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Jeoung, Doo-Il, L. J. W. M. Oehlen, and Frederick R. Cross. "Cln3-Associated Kinase Activity inSaccharomyces cerevisiae Is Regulated by the Mating Factor Pathway." Molecular and Cellular Biology 18, no. 1 (January 1, 1998): 433–41. http://dx.doi.org/10.1128/mcb.18.1.433.
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ABSTRACT The Saccharomyces cerevisiae cell cycle is arrested in G1 phase by the mating factor pathway. Genetic evidence has suggested that the G1 cyclins Cln1, Cln2, and Cln3 are targets of this pathway whose inhibition results in G1 arrest. Inhibition of Cln1- and Cln2-associated kinase activity by the mating factor pathway acting through Far1 has been described. Here we report that Cln3-associated kinase activity is inhibited by mating factor treatment, with dose response and timing consistent with involvement in cell cycle arrest. No regulation of Cln3-associated kinase was observed in a fus3 kss1 strain deficient in mating factor pathway mitogen-activated protein (MAP) kinases. Inhibition occurs mainly at the level of specific activity of Cln3-Cdc28 complexes. Inhibition of the C-terminally truncated Cln3-1-associated kinase is not observed; such truncations were previously identified genetically as causing resistance to mating factor-induced cell cycle arrest. Regulation of Cln3-associated kinase specific activity by mating factor treatment requires Far1. Overexpression of Far1 restores inhibition of C-terminally truncated Cln3-1-associated kinase activity. G2/M-arrested cells are unable to regulate Cln3-associated kinase, possibly because of cell cycle regulation of Far1 abundance. Inhibition of Cln3-associated kinase activity by the mating factor pathway may allow this pathway to block the earliest step in normal cell cycle initiation, since Cln3 functions as the most upstream G1-acting cyclin, activating transcription of the G1 cyclins CLN1 and CLN2 as well as of the S-phase cyclins CLB5 and CLB6.
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Labarère, J., and T. Noël. "Mating type switching in the tetrapolar basidiomycete Agrocybe aegerita." Genetics 131, no. 2 (June 1, 1992): 307–19. http://dx.doi.org/10.1093/genetics/131.2.307.
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Abstract The study of fruiting in the basidiomycete Agrocybe aegerita has shown that some haploid homokaryotic strains can spontaneously switch their mating specificities at the two unlinked A and B mating type factors. This event causes the dikaryotisation of primary homokaryons without plasmogamy and leads to the differentiation of sporulating fruit-bodies (pseudo-homokaryotic fruiting). For each mating type factor, the genetic analyses have revealed that: (1) parental and switched mating types segregate meiotically as Mendelian markers, (2) a total of six switched mating type factors (two parental and four nonparental) were obtained from a wild strain, (3) most of the nonparental factors have specificities differing from those of a large series of wild factors, (4) strains with the same expressed mating type can generate different specificities, (5) switching is always restricted to the same mating type in a homokaryon, (6) nonparental types can switch again, and (7) meiosis fixes the specificities to which switching can occur. This suggests, for the first time in filamentous fungi, the existence of a mechanism analogous to the mating type switching in yeasts. We hypothese that both A and B mating type regions in A. aegerita are constituted of three loci, one specialized in expression and two other carrying silent information. Mating type switching in homokaryotic strains would occur by copy transposition of silent A and B information into the expression loci. Moreover, we propose that during meiosis the silent loci are substituted by copies of the expressed loci.
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Yue, Changli, Lora M. Cavallo, J. Andrew Alspaugh, Ping Wang, Gary M. Cox, John R. Perfect, and Joseph Heitman. "The STE12α Homolog Is Required for Haploid Filamentation But Largely Dispensable for Mating and Virulence in Cryptococcus neoformans." Genetics 153, no. 4 (December 1, 1999): 1601–15. http://dx.doi.org/10.1093/genetics/153.4.1601.
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Abstract Cryptococcus neoformans is a fungal pathogen that causes meningitis in immunocompromised hosts. The organism has a known sexual cycle, and strains of the MATα mating type are more virulent than isogenic MATa strains in mice, and they are more common in the environment and infected hosts. A C. neoformans homolog of the STE12 transcription factor that regulates mating, filamentation, and virulence in Saccharomyces cerevisiae and Candida albicans was identified previously, found to be encoded by a novel region of the MATα mating type locus, and shown to enhance filamentous growth when overexpressed. We have disrupted the C. neoformans STE12 gene in a pathogenic serotype A isolate. ste12 mutant strains exhibit a severe defect in filamentation and sporulation (haploid fruiting) in response to nitrogen starvation. In contrast, ste12 mutant strains have only modest mating defects and are fully virulent in two animal models compared to the STE12 wild-type strain. In genetic epistasis experiments, STE12 functions in a MAP kinase cascade to regulate fruiting, but not mating. Thus, the C. neoformans STE12α transcription factor homolog plays a specialized function in haploid fruiting, but it is dispensable or redundant for mating and virulence. The association of the MATα locus with virulence may involve additional genes, and other transcription factors that regulate mating and virulence remain to be identified.
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Wang, Guangying, Kai Chen, Jing Zhang, Shanjun Deng, Jie Xiong, Xionglei He, Yunxin Fu, and Wei Miao. "Drivers of Mating Type Composition in Tetrahymena thermophila." Genome Biology and Evolution 12, no. 12 (September 18, 2020): 2328–43. http://dx.doi.org/10.1093/gbe/evaa197.
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Abstract Sex offers advantages even in primarily asexual species. Some ciliates appear to utilize such reproductive strategy with many mating types. However, the factors determining the composition of mating types in the unicellular ciliate Tetrahymena thermophila are poorly understood, and this is further complicated by non-Mendelian determination of mating type in the offspring. We therefore developed a novel population genetics model to predict how various factors influence the dynamics of mating type composition, including natural selection. The model predicted either the coexistence of all seven mating types or fixation of a single mating type in a population, depending on parameter combinations, irrespective of natural selection. To understand what factor(s) may be more influential and to test the validity of theoretical prediction, five replicate populations were maintained in laboratory such that several factors could be controlled or measured. Whole-genome sequencing was used to identify newly arising mutations and determine mating type composition. Strikingly, all populations were found to be driven by strong selection on newly arising beneficial mutations to fixation of their carrying mating types, and the trajectories of speed to fixation agreed well with our theoretical predictions. This study illustrates the evolutionary strategies that T. thermophila can utilize to optimize population fitness.
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Dorrity, Michael W., Josh T. Cuperus, Jolie A. Carlisle, Stanley Fields, and Christine Queitsch. "Preferences in a trait decision determined by transcription factor variants." Proceedings of the National Academy of Sciences 115, no. 34 (August 1, 2018): E7997—E8006. http://dx.doi.org/10.1073/pnas.1805882115.
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Few mechanisms are known that explain how transcription factors can adjust phenotypic outputs to accommodate differing environments. In Saccharomyces cerevisiae, the decision to mate or invade relies on environmental cues that converge on a shared transcription factor, Ste12. Specificity toward invasion occurs via Ste12 binding cooperatively with the cofactor Tec1. Here, we determine the range of phenotypic outputs (mating vs. invasion) of thousands of DNA-binding domain variants in Ste12 to understand how preference for invasion may arise. We find that single amino acid changes in the DNA-binding domain can shift the preference of yeast toward either mating or invasion. These mutations define two distinct regions of this domain, suggesting alternative modes of DNA binding for each trait. We characterize the DNA-binding specificity of wild-type Ste12 to identify a strong preference for spacing and orientation of both homodimeric and heterodimeric sites. Ste12 mutants that promote hyperinvasion in a Tec1-independent manner fail to bind cooperative sites with Tec1 and bind to unusual dimeric Ste12 sites composed of one near-perfect and one highly degenerate site. We propose a model in which Ste12 alone may have evolved to activate invasion genes, which could explain how preference for invasion arose in the many fungal pathogens that lack Tec1.
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Quinby, Gary E., James P. Dean, and R. J. Deschenes. "Expression of MFA1 and STE6 is sufficient for mating type-independent secretion of yeast a-factor, but not mating competence." Current Genetics 35, no. 1 (February 10, 1999): 1–7. http://dx.doi.org/10.1007/s002940050425.
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Oku, Keiko, Tom A. R. Price, and Nina Wedell. "Does mating negatively affect female immune defences in insects?" Animal Biology 69, no. 1 (2019): 117–36. http://dx.doi.org/10.1163/15707563-20191082.
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Abstract Immunity is an important mechanism of protection against pathogens and parasites. One factor that can influence immunity is mating. During mating, male-derived materials are transferred to females, and the physical contact also involves the potential risk of sexually transmitted infections, and wounding. Thus, mating can challenge a female’s immune system. This review focuses on exploring how immunity and mating interact in female insects. Although mating has been shown to cause female immune responses in several species, the responses do not always match the observed resistance to pathogens/parasites. Mating up-regulates female immune responses while female resistance is reduced compared to virgin females in some species, and vice versa in other taxa. We discuss why mismatches occur and why post-mating female resistance differs among species, and suggest that measured immune responses may not correlate with female resistance. Also, the mating system will play a major role. Polyandrous mating systems can generate intense post-mating sexual conflict, which can impose high costs of mating on females. Reduced female post-mating resistance may be due to direct suppression of female immunity by males. Alternatively, polyandry may increase the risk of sexually transmitted infections. If this is the major factor driving female post-mating resistance, females of polyandrous species should have higher post-mating immunity. To date, there are insufficient numbers of studies to fully answer the question ‘does mating negatively affect female immune defences in insects?’ To elucidate the links between immunity and mating in females, we need more studies in more species with varied mating systems.
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Kanoh, J., A. Sugimoto, and M. Yamamoto. "Schizosaccharomyces pombe zfs1+ encoding a zinc-finger protein functions in the mating pheromone recognition pathway." Molecular Biology of the Cell 6, no. 9 (September 1995): 1185–95. http://dx.doi.org/10.1091/mbc.6.9.1185.
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We isolated the Schizosaccharomyces pombe zfs1 gene as a multicopy suppressor of the sterility caused by overexpression of a double-stranded RNase. The deduced zfs1 gene product of 404 amino acids showed similarity to a mouse growth factor-inducible nuclear protein Nup475. Its C-terminal region carried two putative zinc-fingers, both of which should be intact for the protein to be functional as the suppressor. This protein appeared to localize in nuclei. Disruption of zfs1 was not lethal but conferred deficiency in mating and sporulation. Activation of transcription in response to the mating pheromone signaling was greatly reduced in the zfs1-disrupted cells. The mating deficiency of the zfs1-disruptant was suppressed partially by overexpression of either gpa1, ras1, byr1, or byr2, which are involved in the transmission of the pheromone signal. Disruption of zfs1 reduced both hypersensitivity of the ras1Val17 mutant to the mating pheromone and uncontrolled mating response caused by mutational activation of Gpa1, the G protein alpha subunit coupled to the mating pheromone receptors. However, overexpression of zfs1 could not bypass complete loss of function of either gpa1, ras1, byr1, or byr2. These observations indicate that the function of zfs1 is involved in the mating pheromone signaling pathway, and are consistent with its function being required to fully activate a factor in this pathway, either directly or indirectly.
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Huyer, Gregory, Amy Kistler, Franklin J. Nouvet, Carolyn M. George, Meredith L. Boyle, and Susan Michaelis. "Saccharomyces cerevisiae a-Factor Mutants Reveal Residues Critical for Processing, Activity, and Export." Eukaryotic Cell 5, no. 9 (September 2006): 1560–70. http://dx.doi.org/10.1128/ec.00161-06.
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ABSTRACT The Saccharomyces cerevisiae mating pheromone a-factor provides a paradigm for understanding the biogenesis of prenylated fungal pheromones. The biogenesis of a-factor involves multiple steps: (i) C-terminal CAAX modification (where C is cysteine, A is aliphatic, and X is any residue) which includes prenylation, proteolysis, and carboxymethylation (by Ram1p/Ram2p, Ste24p or Rce1p, and Ste14p, respectively); (ii) N-terminal processing, involving two sequential proteolytic cleavages (by Ste24p and Axl1p); and (iii) nonclassical export (by Ste6p). Once exported, mature a-factor interacts with the Ste3p receptor on MATα cells to stimulate mating. The a-factor biogenesis machinery is well defined, as is the CAAX motif that directs C-terminal modification; however, very little is known about the sequence determinants within a-factor required for N-terminal processing, activity, and export. Here we generated a large collection of a-factor mutants and identified residues critical for the N-terminal processing steps mediated by Ste24p and Axl1p. We also identified mutants that fail to support mating but do not affect biogenesis or export, suggesting a defective interaction with the Ste3p receptor. Mutants significantly impaired in export were also found, providing evidence that the Ste6p transporter recognizes sequence determinants as well as CAAX modifications. We also performed a phenotypic analysis of the entire set of isogenic a-factor biogenesis machinery mutants, which revealed information about the dependency of biogenesis steps upon one another, and demonstrated that export by Ste6p requires the completion of all processing events. Overall, this comprehensive analysis will provide a useful framework for the study of other fungal pheromones, as well as prenylated metazoan proteins involved in development and aging.
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Li, Chao, Li Tao, Zhangyue Guan, Tianren Hu, Sijia Wang, Weihong Liang, Fei Zhao, and Guanghua Huang. "Candida albicans MTLa2 regulates the mating response through both the a-factor and α-factor sensing pathways." Fungal Genetics and Biology 159 (April 2022): 103664. http://dx.doi.org/10.1016/j.fgb.2022.103664.
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Koenig, Walter D. "Levels of Female Choice in the White-Tailed Skimmer Plathemis Lydia (Odonata: Libellulidae)." Behaviour 119, no. 3-4 (1991): 193–224. http://dx.doi.org/10.1163/156853991x00445.
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AbstractMale Plathemis lydia defend mating territories along the perimeter of ponds. Females come to ponds for brief periods of time every few days to oviposit. During these visits, females actively discriminate among males, rejecting up to 48.9 % of mating attempts. Males varied significantly in the proportion of attempts successfully leading to copulation. However, males that obtained more matings also experienced more rejections. Extensive analyses based on absolute male size, relative male size, and male size relative to female size yielded only marginally significant evidence of female mate preference based on body mass, wing length, wing loading index, or age; to the extent that any of these characters appeared to influence mating success, they similarly influenced refusal rates. The overall weakness of female mate choice is further suggested by the frequency of females ovipositing without prior matings and by the low frequency with which females remate with the same males. On a population basis, females strongly prefer to oviposit in the middle of the day and at particular parts of the study pond. Thus, females exhibit strong choice at several levels. However, despite the high incidence of active female rejection and high variance in male mating success, mate choice is apparently of minor importance in this population. Female discrimination of males, combined with variance in male mating success, are necessary but not sufficient for the action of sexual selection via mate choice. These findings support the prediction that male-male competition is of primary importance in resource control mating systems in which males are able to control female access to most or all favored oviposition sites. However, it is not clear why females generally fail to discriminate among males, given that they have the opportunity to do so. In general, females appear to have low motivation to mate with males, presumably because multiple mating does not significantly increase their fertility or fecundity. Selection for rapid mating may be significant, both because of predation on females during mating and oviposition and because of the risks for males of losing their territories during mating bouts. This time constraint may be the most important factor limiting female discrimination among males on the basis of consistent characteristics.
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Jacobs, Katherine C., and Daniel J. Lew. "Pheromone Guidance of Polarity Site Movement in Yeast." Biomolecules 12, no. 4 (March 26, 2022): 502. http://dx.doi.org/10.3390/biom12040502.
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Cells’ ability to track chemical gradients is integral to many biological phenomena, including fertilization, development, accessing nutrients, and combating infection. Mating of the yeast Saccharomyces cerevisiae provides a tractable model to understand how cells interpret the spatial information in chemical gradients. Mating yeast of the two different mating types secrete distinct peptide pheromones, called a-factor and α-factor, to communicate with potential partners. Spatial gradients of pheromones are decoded to guide mobile polarity sites so that polarity sites in mating partners align towards each other, as a prerequisite for cell-cell fusion and zygote formation. In ascomycetes including S. cerevisiae, one pheromone is prenylated (a-factor) while the other is not (α-factor). The difference in physical properties between the pheromones, combined with associated differences in mechanisms of secretion and extracellular pheromone metabolism, suggested that the pheromones might differ in the spatial information that they convey to potential mating partners. However, as mating appears to be isogamous in this species, it is not clear why any such signaling difference would be advantageous. Here we report assays that directly track movement of the polarity site in each partner as a way to understand the spatial information conveyed by each pheromone. Our findings suggest that both pheromones convey very similar information. We speculate that the different pheromones were advantageous in ancestral species with asymmetric mating systems and may represent an evolutionary vestige in yeasts that mate isogamously.
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Dorer, Russell, Charles Boone, Tyler Kimbrough, Joshua Kim, and Leland H. Hartwell. "Genetic Analysis of Default Mating Behavior in Saccharomyces cerevisiae." Genetics 146, no. 1 (May 1, 1997): 39–55. http://dx.doi.org/10.1093/genetics/146.1.39.
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Haploid Saccharomyces cerevisiae cells find each other during conjugation by orienting their growth toward each other along pheromone gradients (chemotropism). However, when their receptors are saturated for pheromone binding, yeast cells must select a mate by executing a default pathway in which they choose a mating partner at random. We previously demonstrated that this default pathway requires the SPA2 gene. In this report we show that the default mating pathway also requires the AXL1, FUS1, FUS2, FUS3, PEAZ, RVS161, and BNI1 genes. These genes, including SPA2, are also important for efficient cell fusion during chemotropic mating. Cells containing null mutations in these genes display defects in cell fusion that subtly affect mating efficiency. In addition, we found that the defect in default mating caused by mutations in SPA2 is partially suppressed by multiple copies of two genes, FUS2 and MFA2. These findings uncover a molecular relationship between default mating and cell fusion. Moreover, because axl1 mutants secrete reduced levels of a-factor and are defective at both cell fusion and default mating, these results reveal an important role for a-factor in cell fusion and default mating. We suggest that default mating places a more stringent requirement on some aspects of cell fusion than does chemotropic mating.
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Rose, M. D., B. R. Price, and G. R. Fink. "Saccharomyces cerevisiae nuclear fusion requires prior activation by alpha factor." Molecular and Cellular Biology 6, no. 10 (October 1986): 3490–97. http://dx.doi.org/10.1128/mcb.6.10.3490-3497.1986.
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We have developed a protocol for efficient fusion of spheroplasts of the same mating type. Nuclear fusion in this whole-cell system is also efficient and closely parallels nuclear fusion in heterosexual mating of intact cells. In the spheroplast fusion system, nuclear fusion is dependent on both the KAR1 gene and prior exposure to alpha factor. The major products of nuclear fusion in the spheroplast fusion assay were true diploids that were homozygous at the mating-type locus. An additional 10% of the products were cells of ploidy greater than diploid. The dependence of nuclear fusion on alpha factor treatment could not be replaced by synchronization in G1 by mutations in CDC28 and CDC35 or by prior arrest in stationary phase. These data suggest that nuclear fusion is not a constitutive function of the nucleus, but rather is specifically induced by mating hormone.
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Rose, M. D., B. R. Price, and G. R. Fink. "Saccharomyces cerevisiae nuclear fusion requires prior activation by alpha factor." Molecular and Cellular Biology 6, no. 10 (October 1986): 3490–97. http://dx.doi.org/10.1128/mcb.6.10.3490.
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We have developed a protocol for efficient fusion of spheroplasts of the same mating type. Nuclear fusion in this whole-cell system is also efficient and closely parallels nuclear fusion in heterosexual mating of intact cells. In the spheroplast fusion system, nuclear fusion is dependent on both the KAR1 gene and prior exposure to alpha factor. The major products of nuclear fusion in the spheroplast fusion assay were true diploids that were homozygous at the mating-type locus. An additional 10% of the products were cells of ploidy greater than diploid. The dependence of nuclear fusion on alpha factor treatment could not be replaced by synchronization in G1 by mutations in CDC28 and CDC35 or by prior arrest in stationary phase. These data suggest that nuclear fusion is not a constitutive function of the nucleus, but rather is specifically induced by mating hormone.
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Achstetter, T. "Regulation of alpha-factor production in Saccharomyces cerevisiae: a-factor pheromone-induced expression of the MF alpha 1 and STE13 genes." Molecular and Cellular Biology 9, no. 10 (October 1989): 4507–14. http://dx.doi.org/10.1128/mcb.9.10.4507-4514.1989.
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Production of the mating pheromone alpha-factor was examined in Saccharomyces cerevisiae MAT alpha cells that had been exposed to the mating pheromone a-factor. A 2-h treatment with a-factor caused a significant increase in alpha-factor concentration in the medium as demonstrated by a halo assay. MF alpha 1 is one of the two genes coding for a precursor of alpha-factor. A Northern (RNA) analysis of total RNA from a-factor-treated MAT alpha cells revealed a rapid two- to threefold increase in MF alpha 1 transcript levels, reaching maximum within 60 min of exposure to the pheromone. Pheromone induction did not require ongoing protein synthesis. a-Factor-induced MF alpha 1 expression was quantitated by analysis of an MF alpha 1::SUC2 fusion gene whose product was assayed for invertase activity. Expression of the MF alpha 1::SUC2 gene in MAT alpha cells responded to the a-factor signal like the chromosomal version of MF alpha 1. Maturation of the alpha-factor precursor involves three proteolytic activities which are encoded by the KEX1, KEX2, and STE13 genes, respectively. Two of these genes, namely, KEX2 and STE13, were examined for pheromone-induced expression. Only the STE13 gene exhibited pheromone induction at the transcriptional level.
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Achstetter, T. "Regulation of alpha-factor production in Saccharomyces cerevisiae: a-factor pheromone-induced expression of the MF alpha 1 and STE13 genes." Molecular and Cellular Biology 9, no. 10 (October 1989): 4507–14. http://dx.doi.org/10.1128/mcb.9.10.4507.
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Production of the mating pheromone alpha-factor was examined in Saccharomyces cerevisiae MAT alpha cells that had been exposed to the mating pheromone a-factor. A 2-h treatment with a-factor caused a significant increase in alpha-factor concentration in the medium as demonstrated by a halo assay. MF alpha 1 is one of the two genes coding for a precursor of alpha-factor. A Northern (RNA) analysis of total RNA from a-factor-treated MAT alpha cells revealed a rapid two- to threefold increase in MF alpha 1 transcript levels, reaching maximum within 60 min of exposure to the pheromone. Pheromone induction did not require ongoing protein synthesis. a-Factor-induced MF alpha 1 expression was quantitated by analysis of an MF alpha 1::SUC2 fusion gene whose product was assayed for invertase activity. Expression of the MF alpha 1::SUC2 gene in MAT alpha cells responded to the a-factor signal like the chromosomal version of MF alpha 1. Maturation of the alpha-factor precursor involves three proteolytic activities which are encoded by the KEX1, KEX2, and STE13 genes, respectively. Two of these genes, namely, KEX2 and STE13, were examined for pheromone-induced expression. Only the STE13 gene exhibited pheromone induction at the transcriptional level.
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Oróstica, María L., Lidia M. Zuñiga, Daniella Utz, Alexis Parada-Bustamante, Luis A. Velásquez, Hugo Cardenas, and Pedro A. Orihuela. "Tumour necrosis factor-α is the signal induced by mating to shutdown a 2-methoxyestradiol nongenomic action necessary to accelerate oviductal egg transport in the rat." REPRODUCTION 145, no. 2 (February 2013): 109–17. http://dx.doi.org/10.1530/rep-12-0389.
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Mating shut down a 2-methoxyestradiol (2ME) nongenomic action necessary to accelerate egg transport in the rat oviduct. Herein, we investigated whether tumour necrosis factor-α (TNF-α) participates in this mating effect. In unmated and mated rats, we determined the concentration of TNF-α in the oviductal fluid and the level of the mRNA for Tnf-a (Tnf) and their receptors Tnfrsf1a and Tnfrsf1b in the oviduct tissues. The distribution of the TNFRSF1A and TNFRSF1B proteins in the oviduct of unmated and mated was also assessed. Finally, we examined whether 2ME accelerates oviductal egg transport in unmated rats that were previously treated with a rat recombinant TNF-α alone or concomitant with a selective inhibitor of the NF-κB activity. Mating increased TNF-α in the oviductal fluid, but Tnf transcript was not detected in the oviduct. The mRNA for TNF-α receptors as well as their distribution was not affected by mating, although they were mainly localized in the endosalpinx. Administration of TNF-α into the oviduct of unmated rats prevented the effect of 2ME on egg transport. However, the NF-κB activity inhibitor did not revert this effect of TNF-α. These results indicate that mating increased TNF-α in the oviductal fluid, although this not associated with changes in the expression and localization of TNF-α receptors in the oviductal cells. Furthermore, TNF-α mimicked the effect of mating on the 2ME-induced egg transport acceleration, independently of the activation of NF-κB in the oviduct. We concluded that TNF-α is the signal induced by mating to shut down a 2ME nongenomic action in the rat oviduct.
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Fujimura, H. "Identification and characterization of a mutation affecting the division arrest signaling of the pheromone response pathway in Saccharomyces cerevisiae." Genetics 124, no. 2 (February 1, 1990): 275–82. http://dx.doi.org/10.1093/genetics/124.2.275.
Full textAbstract:
Abstract Mating pheromones, a- and alpha-factors, arrest the division of cells of opposite mating types, alpha and a cells, respectively. I have isolated a sterile mutant of Saccharomyces cerevisiae that is defective in division arrest in response to alpha-factor but not defective in morphological changes and agglutinin induction. The mutation was designated dac2 for division arrest control by mating pheromones. The dac2 mutation was closely linked to gal1 and was different from the previously identified cell type nonspecific sterile mutations (ste4, ste5, ste7, ste11, ste12, ste18 and dac1). Although dac2 cells had no phenotype in the absence of pheromones, they showed morphological alterations and divided continuously in the presence of pheromones. As a result, dac2 cells had a mating defect. The dac2 mutation could suppress the lethality caused by the disruption of the GPA1 gene (previously shown to encode a protein with similarity to the alpha subunit of mammalian G proteins). In addition, dac2 cells formed prezygotes with wild-type cells of opposite mating types, although they could not undergo cell fusion. These results suggest that the DAC2 product may control the signal for G-protein-mediated cell-cycle arrest and indicate that the synchronization of haploid yeast cell cycles by mating pheromones is essential for cell fusion during conjugation.