Meeting Abstract

79.3  Monday, Jan. 6 10:30  Identifying crucial microRNAs supporting extreme anoxia tolerance of annual killifish embryos RIGGS, C.L.*; PODRABSKY, J.E.; Portland State University, OR; Portland State University, OR rclaire@pdx.edu

Investigating the physiological mechanisms of anoxia tolerance and ischemic preconditioning in vertebrates strengthens our understanding and application of anoxia survival strategies. This study examines the role of microRNA expression associated with anoxia tolerance of Austrofundulus limnaeus embryos, a highly anoxia tolerant vertebrate. Embryos of A. limnaeus appear to share many characteristics with anoxia intolerant species in their response to anoxia, yet are able to survive for months in the complete absence of oxygen. Thus, it is likely that this species has evolved novel mechanisms to support anoxia tolerance. Several recent studies indicate a potential role for microRNA in metabolic depression during anoxia tolerance, through gene silencing. We hypothesize that changes in miRNA expression during exposure to and recovery from anoxia will identify molecular pathways central to supporting survival of anoxia in A. limnaeus embryos. miRNA and mRNA expression patterns were profiled in A. limnaeus embryos sampled prior to and following a 24-hour anoxic exposure. Roughly 1000 highly differentially expressed miRNAs have been identified, many of which display high sequence homology to mitochondrial transcripts. Putative mRNA targets for miRNAs of interest were identified using in silico target prediction. To test in vivo function we designed and injected Vivo-Morpholinos (Gene-Tools, Philomath, OR) to knockdown expression of miRNAs of interest, and subsequently assessed embryos for changes in their anoxia tolerance. These data provide the first detailed study of miRNA expression and function during exposure to anoxia, and may lead to a better understanding of the molecular pathways, particularly involving mitochondria, that support anoxia tolerance in vertebrates.