Molecular coevolution of a sex pheromone and its receptor triggers reproductive isolation in Schizosaccharomyces pombe
Molecular coevolution of a sex pheromone and its receptor triggers reproductive isolation in Schizosaccharomyces pombe
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DOI：
10.1073/pnas.1501661112
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
Taisuke Seike;Taro Nakamura;C. Shimoda
中科院分区：
文献类型：
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作者：
Taisuke Seike;Taro Nakamura;C. Shimoda
意义正如对自然界现存种群的观察所表明的那样，生殖隔离是导致物种形成的关键事件。本文表明，新的生殖群体裂殖酵母粟酒裂殖酵母，这是生殖隔离的野生型人口，可以通过遗传改变交配信息素及其受体的一级结构。根据生物学的物种概念，这一繁殖群应被视为一个新物种。据我们所知，这是进化研究史上第一次人工创造任何生物体的新物种。性信息素的多样化被认为是导致物种形成的前合子隔离的原因之一。在裂殖酵母裂殖酵母中，肽信息素受体对肽信息素的分子识别在有性生殖中起着至关重要的作用。我们认为，肽交配信息素，M因子，和它的受体，地图3的分子共同进化，可能会通过实验实现这些蛋白质的多样化。在这里，我们报告成功地创建新的交配型对通过搜索图3抑制突变，挽救不育的M-因子突变体，以前被隔离。发现几个强抑制因子也识别WT M因子。这些Map 3抑制子的取代残基被定位到F204、F214和E249，它们可能是M-因子识别的关键残基。这些关键残基通过体外诱变被其他氨基酸中的每一个系统地取代。最终，我们成功地获得了三个新的交配型对构成生殖群体。这些新的交配型对不能与野生型配对。此外，在新的和WT交配对之间没有发生染色体整合的耐药基因的流动，这表明每个实验产生的生殖组[例如，M因子（V5 H）和Map 3（F214 H）]。总之，我们已经成功地创建了一个人工生殖组，是从WT组隔离。按照生物学的物种概念，人工繁殖群是一个新的物种。
Significance Reproductive isolation is a key event leading to speciation as suggested by the observation of living populations in nature. This paper shows that novel reproductive populations of Schizosaccharomyces pombe, which are reproductively isolated from the WT population, can be created by genetically altering the primary structure of a mating pheromone and its receptor. Based on the biological concept of species, this reproductive group should be regarded as a new species. This is the first report, to our knowledge, of the artificial creation of a new species of any living organism in the history of evolutional research. 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.