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

Weaver Ryan J, Auburn AL

Investigators

Abstract

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.