NSF Postdoctoral Fellowship in Biology FY 2019: The role of mitochondrial respiratory chain composition in facultative sexual reproduction

该行动为2019财年美国国家科学基金会生物学博士后研究奖学金提供资金，扩大生物学中代表性不足群体的参与。该奖学金支持研究员的一项研究和培训计划，该计划将增加生物学中代表性不足的群体的参与。本研究旨在增加对线粒体（负责细胞大部分能量的细胞器）在调节动物对变化的环境和繁殖模式的应激反应中的作用的理解。一些动物通过克隆自己来繁殖，而另一些动物通过与其他个体交配来繁殖。动物从自我克隆转向交配作为一种繁殖方式的条件与环境压力有关。过度的环境压力会损害动物的细胞和DNA。在进化的背景下，交配是修复DNA损伤以及创造新基因以适应环境的一种手段。这项工作将研究线粒体如何参与这一过程。除了提出的线粒体研究工作外，该研究员还开发了科学培训和教育计划：增加代表性不足人群的参与（STEP IT UP），以促进和提供公平的生物科学职业机会。STEP IT UP关注的是第一代和少数族裔学生，他们可能仅仅因为成绩或考试分数就被剥夺了研究机会。该研究员将通过STEP IT UP招收学生，以增加生物学中代表性不足的群体的代表性。本项目将研究具有AOX的兼性交配生物Nematostella vectensis海葵的线粒体特征。线粒体呼吸链通常被描述为有两个入口点和一个电子出口。然而，许多兼性动物有第二个出口，称为替代氧化酶（AOX）。这项工作表明，在环境胁迫下，AOX保护细胞免受自由基损伤，通过这种保护，AOX允许在更广泛的环境条件下进行克隆繁殖。AOX在细胞应激条件下维持线粒体功能，同时保持自由基低于导致DNA损伤的水平。将创建AOX的化学抑制和基因敲除谱系，以测试环境应激、自由基和AOX如何相互作用以决定繁殖模式。这名研究员将使用有和没有AOX的谱系进行压力实验，然后测量配子体发生的时间点。如果AOX在向交配形式的繁殖转换中发挥了中介作用，那么AOX敲除谱系应该比野生型谱系产生更多的自由基，并在更低的胁迫阈值下切换繁殖模式。AOX可能在其他进化过程中发挥作用，如DNA突变率、局部适应和物种形成。来自德克萨斯州代表性不足群体的参与者将接受生物信息学、分子生物学和进化生物学方面的培训。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。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2019, Broadening Participation of Groups Under-represented in Biology. The fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. This research aims to increase understanding of the role of mitochondria (the organelle responsible for a majority of the cell's energy) in mediating animal's stress responses to changing environments and mode of reproduction. Some animals reproduce by making clones of themselves while others reproduce by mating with other individuals. The conditions under which an animal switches from making clones of itself to mating as a form of reproduction has been linked to environmental stress. Excessive environmental stress can damage an animal's cells and DNA. In an evolutionary context, mating is a means to repair DNA damage as well as to create new genes that will allow for adaptation to the environment. This work will study how the mitochondria are involved in this process. In addition to the work proposed to study mitochondria, the fellow has developed the Science Training and Education Program: Increasing The participation of Under-represented Populations (STEP IT UP) to promote and provide equitable access to a career in biological science. STEP IT UP focuses on first generation and racial minority students who may be denied research opportunities because of their grades or test scores alone. The fellow will recruit students through STEP IT UP to increase representation of underrepresented groups in biology.This project will investigate mitochondrial characteristics of the sea-starlet anemone, Nematostella vectensis, which is facultatively mating organism and has AOX. The mitochondrial respiratory chain is typically depicted as having two entry points and one exit for electrons. However, many facultative animals have a second exit, called the alternative oxidase (AOX). This work proposes that AOX protects cells from free radical damage during environmental stress and that through this protection, AOX allows for the clonal mode of reproduction under a wider breadth of environmental conditions. AOX maintains mitochondrial function under cellular stress conditions while keeping free radicals below levels that cause damage to DNA. Chemical inhibition of AOX and genetic knockout lineages will be created to test how environmental stress, free radicals, and AOX interact to determine mode of reproduction. The fellow will conduct stress experiments using lineages with and without AOX, then measure the point at which gametogenesis occurs. If AOX plays a role in mediating the switch to a mating form of reproduction, AOX knockout lineages should produce more free radicals and switch reproduction mode at a lower stress threshold than wild type lineages. AOX may play a role in other evolutionary processes such as DNA mutation rates, local adaptation, and speciation. STEP IT UP participants from under-represented groups in Texas will receive training in bioinformatics, molecular biology, and evolutionary biology.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.