Translation regulation of gene expression in toxic dinoflagellates

描述(由申请人提供) 已知有许多甲藻能产生强效的神经毒素。它们的水华通常被称为“赤潮”。了解影响水华生长的遗传调控机制，特别是开发生物标志物以评估水华生长状况，对于制定科学合理的管理和缓解政策至关重要。这些生物的遗传组织和调控已被证明不同于非原生生物。甲藻以其极大的基因组而引人注目，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，这些拷贝通过耦合的反式剪接和聚腺苷酸化进行多顺反子处理。广泛的研究表明，信使核糖核酸的募集是基因表达调控的主要部位。然而，关于翻译起始及其在这些生物体中的调控，人们了解的相对较少。这项应用的目标是解开可能在翻译调控中的关键角色eIF2和eIF4的作用，以及拼接的前导帽结构在调控基因表达中的作用。研究人员将利用冰毒甲藻、褐斑角藻和产生短角叉尾轮藻的毒素，a)确定eIF2-α磷酸化的变化是否是基因表达变化或对不同应激源反应的基础；b)开始表征K.veneficum eIF2-α-激酶的特征；c)表征K.veneficum eIF4E家族成员与帽结构和翻译结合伙伴结合的能力；d)评估K.veneficum eIF4E成员在mRNA募集中的作用。研究人员目前对翻译调控的理解主要来自对小鼠、酵母和植物的研究，不允许真核生物的多样性，其中大部分是在原生动物中发现的。研究人员的结果有望为甲藻的翻译调控定义一个新的范式，并代表一种创新的方法，以增加我们对翻译过程本身的理解，并弥合基因组学与甲藻生理复杂性之间的差距。鉴于翻译在甲藻基因表达中的核心作用，这将 提供与甲藻生长、毒性和有害藻华调控相关的关键洞察力。 与公共卫生相关：一些甲藻物种已知能产生强有力的神经毒素。它们的水华通常被称为“赤潮”。研究人员正在研究这些生物调节其生长和对环境做出反应的机制。由于其独特的基因组结构，甲藻以不寻常的方式进行自我调节。这里提出的研究将对与甲藻生长、毒性和有害藻华调控相关的机制提供关键的洞察，长期目标是提供干预途径。

DESCRIPTION (provided by applicant) 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 is 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 non-protist 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. The goal of this application is 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, the investigators will a) determine whether changes in eIF2-alpha phosphorylation underlie dial changes in gene expression or responses to different stressors; b) begin characterization of the eIF2-alpha-kinases from K. veneficum; c) characterize the ability of K.veneficum eIF4E family member to bind to cap structures and translational binding partners; d) assess the role of K.veneficum eIF4E members in mRNA recruitment. The investigators current understanding of translational regulation is derived mainly from studies in mouse, yeast and plants and does not allow for the diversity of eukaryotic life, the bulk of which is to be found in the Protista. The investigators' results are expected to define a new paradigm for translational regulation in dinoflagellates and represent an innovative approach to increase our understanding of the translational process itself as well as to bridge the gap between genomics and physiological complexity in dinoflagellates. Given the central role of translation in dinoflagellate gene expression, this will provide critical insight into mechanisms relevant to dinoflagellate growth, toxicity, and the regulation of harmful algal blooms. Public Health Relevance: A number of dinoflagellate species are known to produce potent neurotoxins. Their blooms are commonly referred to as ''red tides.'' The investigators are studying the mechanisms by which these organisms can regulate their growth and respond to the environment. Because of their unique genome structure, dinoflagellates regulate themselves in unusual ways. The studies proposed here will provide critical insight into mechanisms relevant to dinoflagellate growth, toxicity, and the regulation of harmful algal blooms, with a lon term goal of providing avenues for intervention.