Co-option of the hormone-signalling module dafachronic acid-DAF-12 in nematode evolution
Co-option of the hormone-signalling module dafachronic acid-DAF-12 in nematode evolution
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DOI：
10.1038/nature09164
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发表时间：
2010-07-22
期刊：
影响因子：
64.8
通讯作者：
Sommer, Ralf J.
中科院分区：
文献类型：
--
作者：
Bento, Gilberto;Ogawa, Akira;Sommer, Ralf J.
形态学上的新颖性是具有新功能的谱系特异性特征（1，2）。发育多型性被认为是表型进化的促进因素，但对相关遗传和环境因素之间的相互作用知之甚少（3-11）。在这里，我们研究了两种不同的形态，在口的线虫Pristionchus pacificus和牙齿状结构的形成，与食菌性喂养和捕食行为的真菌和其他蠕虫（12-16）。这些牙齿状的寄生虫代表了一种进化上的新奇，它仅限于线虫科Diplogastridae的一些成员，但在秀丽隐杆线虫和相关线虫中不存在（14）。我们表明，嘴的二型性是一个多型性，是由饥饿和内分泌开关机制的选择。核激素受体α-12的突变及其配体固醇激素达法膦酸的应用强烈影响了这种转换机制。在两种C. elegans和P. pacificus，以及远亲线虫的相关生活史决定（17-20）。dauer形成和口腔形态转换的比较揭示了不同的达法膦酸信号传导阈值提供了特异性。这项研究表明，激素信号是如何通过耦合环境变化和遗传调控的作用，并确定dafachronic酸作为线虫进化的关键激素。
Morphological novelties are lineage-specific traits that serve new functions(1,2). Developmental polyphenisms have been proposed to be facilitators of phenotypic evolution, but little is known about the interplay between the associated genetic and environmental factors(3-11). Here, we study two alternative morphologies in the mouth of the nematode Pristionchus pacificus and the formation of teeth-like structures that are associated with bacteriovorous feeding and predatory behaviour on fungi and other worms(12-16). These teeth-like denticles represent an evolutionary novelty, which is restricted to some members of the nematode family Diplogastridae but is absent from Caenorhabditis elegans and related nematodes(14). We show that the mouth dimorphism is a polyphenism that is controlled by starvation and the co-option of an endocrine switch mechanism. Mutations in the nuclear hormone receptor DAF-12 and application of its ligand, the sterol hormone dafachronic acid, strongly influence this switch mechanism. The dafachronic acid-DAF-12 module has been shown to control the formation of arrested dauer larvae in both C. elegans and P. pacificus, as well as related life-history decisions in distantly related nematodes(17-20). The comparison of dauer formation and mouth morphology switch reveals that different thresholds of dafachronic acid signalling provide specificity. This study shows how hormonal signalling acts by coupling environmental change and genetic regulation and identifies dafachronic acid as a key hormone in nematode evolution.