Translation Regulation of Gene Expression in Toxic Dinoflagellates

已知许多鞭毛类动物能产生强效的神经毒素。它们的大量繁殖通常被称为“赤潮”。了解影响水华生长的遗传调控机制，特别是开发评估水华生长状况的生物标志物，对于制定科学合理的管理和减缓政策至关重要。这些生物的遗传组织和调控已被证明不同于非原生真核生物。鞭毛藻以其非常大的基因组而闻名，这些基因组几乎没有转录调控，并且基因以多个串联拷贝的形式存在，通过偶联反式剪接和聚腺苷酸化进行多顺反性加工。广泛的研究表明mRNA募集是基因表达调控的主要位点。然而，相对而言，对这些生物的翻译起始及其调控知之甚少。在这个项目中，一个以马里兰大学海洋与环境技术研究所为中心的研究小组将试图揭示在翻译调节中可能的关键角色，eIF2和eIF4，以及拼接的领导帽结构在调节基因表达中的作用。他们将利用鱼毒鞭毛藻、veneficum Karlodinium和产生毒素的短弧菌（Karenia brevis），确定eif2<e:1>磷酸化的变化是否导致了基因表达的变化或对不同应激源的反应；(2)开始对取自veneficum的eIF2á-kinases进行鉴定；(3)表征了veneficum eIF4E家族成员与帽状结构和翻译结合伙伴的结合能力；(4)评估威尼斯镰刀菌eIF4E成员在mRNA募集中的作用。鉴于翻译在鞭毛藻基因表达中的核心作用，这将为鞭毛藻生长、毒性和有害藻华调控的相关机制提供重要的见解。这些结果有望为鞭毛藻的翻译调控定义一个新的范式，从而为弥合基因组学和生理复杂性之间的差距提供了一种创新的方法。了解鞭毛藻基因表达的翻译调控机制可能有助于深入了解这些生物对毒素产生的调控，并可能直接用于监测/管理有害藻华。更广泛的影响：这些研究将提供有关鞭毛藻生长、毒性和有害藻华调控机制的关键见解，并提供干预途径的长期目标。该项目将为高中生、本科生实习生和地区高中教师提供研究经验/培训。由NSF和NIEHS联合资助：该项目的原始提案（R01 ES021949-01）是根据资助机会公告RFA-ES-11-013，“海洋，大湖和人类健康（R01）”提交给国家环境卫生科学研究所（NIH/NIEHS）的，这是一个由NSF联合赞助的机会。本项目由NSF和NIEHS分别合作资助。

A number of dinoflagellate species are known to produce potent neurotoxins. Their blooms are commonly referred to as "red tides". An understanding of the genetic regulatory mechanisms that affect bloom growth and in particular the development of biomarkers to assess bloom growth status are essential for the development of scientifically sound management and mitigation policies. The genetic organization and regulation of these organisms has been shown to be distinct from nonprotist eukaryotes. Dinoflagellates are remarkable for their extremely large genomes that show little transcriptional regulation and with genes present as multiple tandem copies that are polycistronically processed through coupled trans-splicing and polyadenylation. A broad range of investigations has implicated mRNA recruitment as a major site of regulation of gene expression. However, relatively little is understood regarding translational initiation and its regulation in these organisms. In this project, a research team centered at the University of Maryland Institute of Marine and Environmental Technology will attempt to unravel the roles of the likely key players in translational regulation, eIF2 and eIF4, along with the spliced leader cap structures in regulating gene expression. Using the icthyotoxic dinoflagellate, Karlodinium veneficum and the toxin producing Karenia brevis, they will (1) determine whether changes in eIF2á phosphorylation underlie diel changes in gene expression or responses to different stressors; (2) begin characterization of the eIF2á-kinases from K. veneficum; (3) characterize the ability of K.veneficum eIF4E family member to bind to cap structures and translational binding partners; and (4) assess the role of K.veneficum eIF4E members in mRNA recruitment. Given the central role of translation in dinoflagellate gene expression, this should provide significant insight into mechanisms relevant to dinoflagellate growth, toxicity, and the regulation of harmful algal blooms. These results are expected to define a new paradigm for translational regulation in dinoflagellates, thus offering an innovative approach to bridge the gap between genomics and physiological complexity in dinoflagellates. Understanding the mechanism of translational regulation of dinoflagellate gene expression may begin to provide insight into the regulation of toxin production by these organisms and may be of direct use in monitoring/managing harmful algal blooms. Broader Impacts: The studies will provide critical insight into mechanisms relevant to dinoflagellate growth, toxicity, and the regulation of harmful algal blooms, with a long term goal of providing avenues for intervention. The project will provide research experiences/training to high school students, undergraduate interns and area high school teachers. JOINT FUNDING BY NSF AND NIEHS: The original proposal on which this project is based (R01 ES021949-01) was submitted to the National Institutes of Environmental Health Sciences (NIH/NIEHS) in response to Funding Opportunity Announcement RFA-ES-11-013 , "Oceans, Great Lakes and Human Health (R01)", an opportunity jointly sponsored by NSF. This project is cooperatively funded through separate awards from NSF and NIEHS.