P08 : Life in the slow lane: microRNA regulation of cyclin D1 during anoxic stress in Trachemys scripta elegans

Abstract

Natural anoxia tolerance (survival without oxygen) depends on numerous biochemical adaptation that address the stress imposed on cells. These adaptations preserve cell viability by suppressing energy-expensive functions in the anoxic state. We hypothesized that microRNAs could act to establish rapid biological controls that aid the shutting down of cell proliferation. Selected microRNA species known to bind Cyclin D1 (miR-16 and miR-133) were evaluated by RT-PCR in turtles ( Trachemys scripta elegans ) comparing aerobic controls with animals anoxic for 5 and 24 h. Levels of both miR-16 and miR-133 increased significantly during anoxia in kidney and liver tissues; no change was seen in skeletal muscle. Protein levels of Cyclin D1 changed expression levels in a similar pattern to that seen for both evaluated microRNAs. To determine the capacity of selected microRNAs to bind turtle specific Cyclin D1 mRNA, 3′ RACE was used to determine the 3′UTR sequence. Web-based bioinformatics software (RNAHybrid) was used to determine the likelihood of binding in vivo using thermodynamics and 5’seed complementary.