Freeze tolerance in insects is associated with cryoprotectant synthesis and strong metabolic suppression. Freeze avoidance, an alternative strategy in cold-hardy insects, is also characterized by hypometabolism, but possesses significant cellular and physiological differences when compared with freeze tolerance. We hypothesized that microRNAs, noncoding transcripts that bind to mRNA, could play a role in the regulation of energy-expensive mRNA translation in insects exposed to low temperatures. Expression levels of microRNA species were evaluated during cold acclimation of freeze tolerant Eurosta solidaginis and freeze-avoiding Epiblema scudderiana, comparing control (5°C) conditions with larvae given sequential exposures to -5°C and -15°C. MiR-1 levels were significantly elevated in frozen E. solidaginis larvae at -15°C, whereas miR-34 levels were unchanged. MiR-1 and miR-34 levels remained stable in E. scudderiana. These data demonstrate differential microRNA expression in frozen versus control insect larvae and highlight contrasting microRNA signatures between freeze tolerant and freeze avoiding species.

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Keywords Epiblema scudderiana, Eurosta solidaginis, Freeze avoidance, Freeze tolerance, MicroRNA, Reversible control of translation
Journal Cryo-Letters
Lyons, P.J. (Pierre J.), Poitras, J.J. (Julie J.), Courteau, L.A. (Lynn A.), Storey, K, & Morin, P.J. (Pier Jr). (2013). Identification of differentially regulated micrornas in Cold-hardy insects. Cryo-Letters, 34(1), 83–89.