scholarly journals Asymmetric diversification of mating pheromones in fission yeast

PLoS Biology ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. e3000101 ◽  
Author(s):  
Taisuke Seike ◽  
Chikashi Shimoda ◽  
Hironori Niki
1995 ◽  
Vol 15 (9) ◽  
pp. 4964-4970 ◽  
Author(s):  
M Willer ◽  
L Hoffmann ◽  
U Styrkársdóttir ◽  
R Egel ◽  
J Davey ◽  
...  

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.


2019 ◽  
Vol 132 (12) ◽  
pp. jcs230722 ◽  
Author(s):  
Taisuke Seike ◽  
Hiromi Maekawa ◽  
Taro Nakamura ◽  
Chikashi Shimoda

2018 ◽  
Author(s):  
Taisuke Seike ◽  
Chikashi Shimoda ◽  
Hironori Niki

AbstractIn fungi, mating between partners critically depends on the molecular recognition of two peptidyl mating pheromones by their respective receptors. The fission yeast Schizosaccharomyces pombe has two mating types, Plus (P) and Minus (M), which secrete two different mating pheromones: P-factor recognized by Mam2, and M-factor recognized by Map3, respectively. Our recent study demonstrated that a few mutations in both M-factor and Map3 can trigger reproductive isolation, a cause of speciation, in S. pombe. Here we explored the mechanism underlying reproductive isolation through genetic changes of pheromones and receptors. We investigated the diversity of genes encoding the pheromones and their receptor in 150 S. pombe wild 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). We also explored the recognition specificity of pheromones between S. pombe (Sp) and its close relative Schizosaccharomyces octosporus (So). 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, allowing them to mate successfully. Thus, recognition of M-factor seems to be tight, whereas that of P-factor is relatively loose. Moreover, diversity of P-factor and Mam2 might be due to a P-factor-specific peptidase. Overall, the asymmetric system for pheromone recognition in yeasts seems to allow flexible adaptation to mutational changes in the combination of pheromone and receptor while maintaining tight recognition for mating partners.


Author(s):  
Atsuko Shirai ◽  
Akihisa Matsuyama ◽  
Yoko Yashiroda ◽  
Ritsuko Arai ◽  
Minoru Yoshida

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