Abstract
Upon dehydration, the sleeping chironomid (Polypedilum vanderplanki) larvae decrease water content and simultaneously increase trehalose content, to eventually enter into a state of a metabolically suspended animation, i.e., anhydrobiosis, after 48 h of the treatment. Intriguingly, the desiccated larvae can resume the activity once rehydrating. In addition to trehalose content elevation, expression of genes encoding stress-related proteins, such as HSP and LEA proteins, are thought to be deeply involved in desiccation tolerance. However, fine molecular mechanisms underlying anhydrobiosis have remained to be elucidated. Exhaustive gene expression analysis using microarray technique showed that a large number of genes annotated as related to protein degradation mechanisms, including ubiquitin-proteasome system, ER-associated protein degradation and lysosomal hydrolases was upregulated in the larvae upon dehydration. Based on the result, we expected that protein degradation might play an important role to invoke desiccation tolerance.
