BRC-BIO: Evolutionary Patterns of Ice-Binding Proteins in North Pacific Intertidal Invertebrates

生活在极地地区的动物必须在一年中几个月的严寒中生存下来。冰冻的水，特别是冰晶，会损害软组织，杀死不适应冰冻条件的生物。从鱼类到甲虫再到细菌，许多物种已经发展出了抵御冰冻条件的生理机制，最引人注目的是它们产生了与冰结合的蛋白质，其中一些被称为“防冻”蛋白质。就像汽车里的防冻液可以降低水的冰点一样，防冻蛋白可以保护生物体组织免受冰晶的破坏。人们对海星等海洋无脊椎动物体内的这些蛋白质知之甚少，而海星是潮间带栖息地的重要捕食者。最近的遗传证据表明，海星可能会产生这些蛋白质的新形式。这项研究将调查潮间带海星在阿拉斯加低于冰点的水中产生蛋白质的能力背后的遗传机制，以及蛋白质的产生如何随着季节和温度的变化而变化。了解这些蛋白质的功能和触发它们产生的环境条件将使研究人员能够预测海星如何适应极端气候事件。这项工作的结果可能有助于发展海星近亲海参和海胆等无脊椎动物的海水养殖业。此外，如果海星产生新的蛋白质，它们的发现可能会导致生物医学冷冻保存和商业农业的创新。该项目将为本科生，特别是阿拉斯加原住民，通过指导、研究、研讨会和专业发展，创造学习STEM专业技能的机会。与远洋（开阔水域）和底栖（深海）动物相比，极地潮间带无脊椎动物克服了独特的环境挑战，包括冬季温度的每日大幅波动。冰冻条件会通过在软组织上形成冰晶而导致致命的细胞损伤。许多适应寒冷的恒温生物已经进化出通过产生冰结合蛋白（IBPs）来防止寒冷损害的机制。IBPs与冰晶平面结合，具有多种功能，从冰的再结晶和生长抑制（防冻）到控制冰的形成（成核）。最近的证据提供了在海洋无脊椎动物中发现新的ibp的潜力。该项目的目的是描述IBP生产存在的程度，以及主要居住在北极和亚北极的潮间带无脊椎动物的选择谱系与环境的相关性。该项目将结合冷冻分析、基因组测序和转录组测序来表征几个潮间带无脊椎动物谱系中IBPs的进化特征，以确定生活在北太平洋的一个潮间带无脊椎动物（棘皮动物）分支的冰结合活性，确定IBPs的类别和两个预测具有冰结合活性和耐寒性的棘皮动物海星谱系的功能基因区域。并量化海星不同季节和温度梯度的IBP产量（基因表达）。这项研究将通过量化数十种潮间带物种的冰结合活动来解决冷水适应领域的一个主要空白。该项目由生物科学理事会和促进竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Animals living in polar regions must survive freezing conditions for several months of the year. Freezing water, specifically ice crystals, can damage soft tissues and kill organisms that are not adapted to freezing conditions. Several species – from fish to beetles to bacteria – have developed physiological mechanisms to withstand freezing conditions, most notably by producing proteins that bind to ice, some of which are called ‘antifreeze’ proteins. Just as antifreeze solution in a car lowers the freezing point of water, antifreeze proteins protect organisms’ tissues from damaging ice crystals. Little is known about these proteins in marine invertebrates such as sea stars, which are important predators in intertidal habitats. Recent genetic evidence suggests sea stars may produce new forms of these proteins. This study will investigate the genetic mechanisms behind intertidal sea stars’ ability to produce proteins to survive in sub-freezing water in Alaska and how protein production varies by season and temperature. Understanding the function of these proteins and the environmental conditions that trigger their production will allow researchers to make predictions on how sea stars will adapt to extreme climatic events. The results from this work may aid the growing mariculture industry for invertebrates such as sea cucumbers and urchins, which are close relatives of sea stars. Furthermore, if sea stars produce novel proteins, their discovery may lead to innovations in biomedical cryopreservation and commercial agriculture. This project will create opportunities for undergraduates, particularly Alaska Natives, to learn professional skills in STEM through mentoring, research, workshops and professional development.Intertidal invertebrates in polar regions overcome unique environmental challenges compared to their pelagic (open water) and benthic (deep sea) counterparts, including large daily winter temperature fluctuations. Freezing conditions can lead to lethal cellular damage through the formation of ice crystals on soft tissues. Many cold-adapted ectothermic organisms have evolved mechanisms to prevent damage from cold by producing ice-binding proteins (IBPs). IBPs bind to ice crystal planes and have a variety of functions, from ice recrystallization and growth inhibition (antifreeze) to the controlled formation (nucleation) of ice. Recent evidence offers potential for discovering novel IBPs in marine invertebrates. The objective of this project is to describe the extent to which IBP production exists and is environmentally correlated across select lineages of intertidal invertebrates that primarily inhabit the Arctic and subarctic. The project will combine freezing assays with genome and transcriptome sequencing to characterize the evolution of IBPs in several lineages of intertidal invertebrates to determine ice-binding activity in one clade of intertidal invertebrates (Echinodermata) inhabiting the North Pacific, identify the class of IBPs and functional gene regions in two lineages of echinoderm sea stars predicted to exhibit ice-binding activity and cold tolerance, and quantify IBP production (gene expression) in sea stars across seasons and temperature gradients. The research will address a major gap in the field of cold-water adaptation by quantifying ice-binding activity in dozens of intertidal species.This project is jointly funded by the Directorate for the Biological Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.