mRNA Translation and Germline Evolution in Caenorhabditis

秀丽隐杆线虫的 mRNA 翻译和种系进化

• 批准号: 1355119
• 负责人: Eric Haag
• 金额: $ 64.5万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-15 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1355119&HistoricalAwards=false
• 关键词: mRNA; Translation; Germline; Evolution; Caenorhabditis

One of the grand challenges of evolutionary biology is to understand how new anatomical features emerge without disrupting the overall coherence of development. Because many genes that control development are widely conserved, the process must blend both ancient components and new features, such as species-specific genes or regulatory connections between genes. This research examines an ecologically important novelty that has evolved repeatedly in Caenorhabditis nematodes--self-fertile hermaphroditism. A key step in the evolution of self-fertility was the ability of otherwise female worms to produce a limited number of sperm, which turned them into hermaphrodites. Hermaphrodite sperm production is regulated by messenger RNA-binding proteins (RBPs) present in the germ cells (the precursors of gametes). One of these RBPs, GLD-1, is an ancient, slow-evolving protein that regulates hundreds of target mRNAs. GLD-1 was coopted into hermaphrodite germ line sex determination independently in two different species, C. elegans and C. briggsae. However, in C. elegans GLD-1 promotes sperm fate, whereas in C. briggsae GLD-1 represses it. This paradox is explained by the species-specific evolution of GLD-1 protein cofactors and by changes in the sequences of the mRNA molecules that GLD-1 binds. This project will work with several Caenorhabditis species to systematically examine how both cofactors and mRNA sequence changes alter the context of GLD-1 activity to allow the emergence of a new reproductive strategy. More generally, this research will help reveal how old molecules can take on new roles, thereby linking evolution at the molecular and organismal scales of biological organization. We will use this project to help local high school teachers understand the excitment of scientific research so they can convey these lessons to their classes.

进化生物学的重大挑战之一是了解新的解剖特征如何在不破坏发育的整体一致性的情况下出现。由于许多控制发育的基因广泛保守，因此该过程必须融合古老的成分和新的特征，例如物种特异性基因或基因之间的调节连接。这项研究检验了秀丽隐杆线虫中反复进化的一种具有重要生态意义的新奇事物——自体受精的雌雄同体。自体受精进化的一个关键步骤是雌性蠕虫产生有限数量精子的能力，这使它们变成雌雄同体。雌雄同体精子的产生受到生殖细胞（配子前体）中存在的信使 RNA 结合蛋白 (RBP) 的调节。其中一个 RBP，GLD-1，是一种古老的、缓慢进化的蛋白质，可调节数百个目标 mRNA。 GLD-1 在两个不同的物种（秀丽隐杆线虫和布里格斯）中独立地被纳入雌雄同体种系性别决定。然而，在线虫中，GLD-1 促进精子的命运，而在布里格斯（C. briggsae）中，GLD-1 则抑制精子的命运。这种悖论可以通过 GLD-1 蛋白辅因子的物种特异性进化以及 GLD-1 结合的 mRNA 分子序列的变化来解释。该项目将与几种秀丽隐杆线虫物种合作，系统地研究辅助因子和 mRNA 序列的变化如何改变 GLD-1 活性的背景，从而出现新的繁殖策略。更一般地说，这项研究将有助于揭示旧分子如何发挥新作用，从而将生物组织的分子和组织尺度上的进化联系起来。 我们将利用这个项目帮助当地高中教师了解科学研究的乐趣，以便他们能够将这些课程传达给他们的班级。