A long noncoding RNA acts as a post-transcriptional regulator of heat shock protein (HSP70) synthesis in the cold hardy Diamesa tonsa under heat shock
Paola Bernabo, Gabriella Viero, Valeria Lencioni|Department of Invertebrate Zoology and Hydrobiology, MUSE-Museo delle Sciencze, Trento, Italy, Institute of Biophysics-CNR Trento Unit, Povo, Trento, Italy|PLOS ONE|2020|15(4): E0227172 https://doi.org/ 10.1371/journal.pone.0227172
Climate change can have a huge impact on high mountain freshwater species as migration and dispersion to escape stressors are hampered by isolation and habitat fragmentation. As a result, cold stenothermal species that have adapted to live at temperatures close to their physiological limits may only survive if they can adapt to new environmental conditions or avoid stressor adopting specific behaviours. Larvae of cold stenothermal species, such as Diamesa tonsa (D. tonsa), are freeze-tolerant with a thermal optimum below 6°C and survive short-term heat shock by developing a heat shock response based on the synthesis of heat shock proteins (HSPs). The aim of the study was to observe how cold stenothermal organisms control gene expression at the transcriptional, translational and protein level under warming conditions using D. tonsa as the target species. D. tonsa Larvae were exposed for 1 hour to three different stress temperatures (15°C, 26°C and 32°C) in plastic bottles filled with 10 mL of preheated filtered and aerated stream water. The temperature was returned to 4°C (rearing temperature) after the treatment period and any living larvae were further analysed. Protein, Total RNA and genomic DNA was extracted from the larvae and analysed by qPCR, RACE, polysomal profiling, western blotting and bioinformatics techniques. It was observed that under heat stress, hsp70 gene, hsp70 pseudogene and two isoforms of hsc70 (Dt-hsc10-I and Dt-hsc70-II) genes in D. tonsa larvae displayed differential expression at transcriptional, translation and protein level. The expression of the pseudogene suggests the existence of a new and unexpected mechanism, to cope with thermal stress by lowering the pace of protein production to save energy and optimize recovery.