Aquaporins (AQPs) are water channel proteins facilitating movement of water across the cell membrane. Recent insect studies clearly demonstrate that AQPs are indispensable for cellular water management under normal conditions as well as under stress conditions including dehydration and cold. In the present study we cloned an AQP cDNA from the Antarctic midge Belgica antarctica (Diptera, Chironomidae) and investigated water transport activity of the AQP protein and transcriptional regulation of the gene in response to dehydration and rehydration. The nucleotide sequence and deduced amino acid sequence of the cDNA showed high similarity to AQPs in other insects and also showed characteristic features of orthodox AQPs. Phylogenetic analysis revealed that Belgica AQP is a homolog of dehydration-inducible AQP of another chironomid, Polypedilum vanderplanki. A swelling assay using a Xenopus oocyte expression system verified that Belgica AQP is capable of transporting water, but not glycerol or urea. The AQP mRNA was detected in various organs under non-stressed conditions, suggesting that this AQP plays a fundamental role in cell physiology. In contrast to our expectation, AQP transcriptional expression was not affected by either dehydration or rehydration.
|Number of pages||9|
|Journal||Journal of Insect Physiology|
|State||Published - Aug 2011|
Bibliographical noteFunding Information:
We dedicate this paper to the memory of Karl Erik Zachariassen, whose friendship and insights on temperature and water relationships in insects we have highly valued. This research was supported by OCU Oversea Science Mission Program from Osaka City University to SGG, and by NSF Grants ANT-0837559 and 0837613 to REL and DLD.
- Water balance
- Water channel proteins
- Xenopus swelling assay
ASJC Scopus subject areas
- Insect Science