MicroRNA Regulation of Insect Diapause

Ohio State University, The, Columbus OH

Investigators

Abstract

Understanding insect diapause is essential for predicting when and where insect populations will be active and abundant. Diapause is an internally regulated dormant state that allows insects to "escape" during seasons, such as winter, when the environmental conditions are harsh and unsuitable or normal growth and activity. Diapause is characterized by changes in development, metabolism, and environmental stress resistance. Although there have been studies that characterized physiological, biochemical, and molecular changes that occur during diapause, the understanding of diapause regulation is far from being complete. This research will provide new information about how diapause is regulated by investigating how small noncoding RNA molecules (microRNAs), regulate diapause. This study will improve our understanding of this important adaptation to changing environmental conditions. This research also has the potential to provide new tools for managing medically and economically important insects. For example, if microRNA function in insect diapause can block or induce diapause entry at a time of year that would be detrimental for their continued survival. This research has the potential to provide novel therapies for human medical disorders, such as cancer and diabetes, which share common, microRNA-associated regulatory mechanisms in humans and insects. Finally, the project will also provide integrative training and mentoring opportunities for multiple undergraduate students, while also broadly disseminating the findings to the public via informal science education to school children and families. Studying insect diapause provides a conceptual frame work for understanding how insects, and other animals, perceive environmental cues and translate them into phenotypic changes that allow them to survive biotic and abiotic challenges they encounter. MicroRNAs (miRNAs, ~22 nucleotide, noncoding RNAs) are evolutionarily conserved, regulatory molecules that have important roles in diapause-relevant biological processes (e.g. developmental arrest, metabolic repression, and stress-resistance) in evolutionarily diverse species. Numerous miRNAs are deferentially regulated during pupal diapause in the flesh fly, Sarcophaga bullata, but their functional relevance is currently unknown. The aim of this project is to identify, and experimentally validate, mRNA targets of diapause-relevant miRNAs using computational and biochemical approaches. Specifically, the project focuses on miRNA:mRNA pairs that may have a role in environmental stress-resistance, a defining feature of the diapause phenotype. It also investigates the evolutionary context of miRNA:mRNA regulatory networks and their contribution to the diapause phenotype in multiple insect species. Together, the results from the proposed research are expected to provide an entirely new dimension to the understanding of insect diapause as well as insights concerning the evolutionary conservation of miRNA:mRNA interactions across Insecta. 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.