RUI: Identifying reproductive roles for the Super-conserved Receptors Expressed in Brain (SREB) G protein-coupled receptor family using novel agonists and a comparative fish model

SREBs (Super-conserved Receptors Expressed in Brain) are a group of hormone receptor proteins in vertebrate animals whose function is poorly understood. This knowledge gap stems from a lack of verified hormones that bind to SREBs on the surface of cells. Previous studies have supported functional roles for SREBs in the brain, gut, and gonads that may be conserved in animals. This project applies novel, artificially synthesized molecules that are known to bind to SREB receptors in ovaries of three fish species to assess SREB function in reproduction. The species were chosen based on previously identified genetic differences resulting in different profiles of SREB subtypes across these species. Results will be compared among the fish species to identify unique and shared functions. The resulting improved understanding of SREB functions may provide a foundation for future commercial applications in animal reproduction and in aquaculture. The research will generate databases that will foster undergraduate and high-school student research experiences in bioinformatics in rural western Maine, which has a high proportion of first-generation college students. Local high-school teachers will be trained to use these databases in their classes and to develop independent bioinformatics modules for sustainable use. These educational activities serve as a scalable model to bring bioinformatics training to under-served student populations, contributing to biotechnology workforce development. In addition, through a collaboration with two researchers at the University of Florida, the project will contribute to training of a graduate student and post-doctoral fellow. The recent development of novel and specific agonists for the orphan G protein-coupled receptor family SREB has enabled new approaches to understand the physiological mechanisms of receptor function. Two synthesized and validated agonist molecules are being used in combination with a potential endogenous ligand (phoenixin) in in vitro ovary treatments and RNA-sequencing of three genetically enabled fish species: zebrafish (Danio rerio), mummichog (Fundulus heteroclitus), and pufferfish (Dichotomyctere nigroviridis). Each of these species exhibits a different complement of SREB receptors, which enables comparative transcriptomic approaches to identify both conserved reproductive functions across the family as well as SREB member-specific effects. These methods will be used in combination with steroid quantifications and RNAScope to identify reproductive hormone changes and specific gonadal cell types associated with SREB gene expression, respectively. The development of this comparative multispecies model impacts future SREB studies beyond reproduction, such as investigations in the brain and gut where SREBs have also been implicated in conserved functions. This project is jointly funded by the BIO-IOS-Physiological Mechanisms and Biomechanics Program 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.