MicroRNA biogenesis and m6A methylation in hyperglycemic wood frog, Lithobates sylvaticus

The freeze-tolerant wood frog (Lithobates sylvaticus) endures extreme hyperglycemia during winter while simultaneously entering metabolic rate depression (MRD). In most vertebrates, elevated glucose promotes anabolic metabolism, however, in the wood frog, hyperglycemia coincides with suppression of energy expensive cellular processes. This thesis examines whether post-transcriptional regulatory mechanisms in the liver are associated with this physiological state under hyperglycemic conditions. Using glucose-injected wood frogs to isolate hyperglycemia from freezing-related stresses, components of the microRNA (miRNA) biogenesis pathway and the N6-methyladenosine (m6A) epitranscriptomic machinery were assessed. Hyperglycemia was associated with altered abundance of miRNA biogenesis proteins, including increased Drosha and reduced Exportin-5, as well as changes in m6A regulatory proteins, characterized by increased FTO and reduced YTHDF1. Together, these findings indicates that hyperglycemia coincides with coordinated modulation of post-transcriptional regulatory pathways in the wood frog liver during MRD.