Cloning and Characterization of Aquaporins 11 and Its Expression Analysis under Molt Cycle in <i>Eriocheir sinensis</i>

Abstract

Aquaporins play important roles in water molecule transport, ion transport, and osmotic pressure regulation. In this study, the full-length cDNA of aquaporin from Chinese mitten crab ( Eirocheir sinensis ) was cloned for first time using reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends analyses. The full-length of AQP11 cDNA is 1746bp, with a 463bp 5’-untranslated region (UTR), a 476bp 3’-UTR, and an open reading frame (ORF) of 807 bp which encodes a 269 amino acid polypeptide. The molecular mass of the predicted protein is 29.46 kDa with an estimated PI of 5.38. Bioinformatics software analysis revealed that AQP11 gene contains 4 transmembrane domains, 2 NPV structural units. Homologous analysis showed that AQP11 of Eirocheir sinensis  has the highest homology to AQP11 of Litopenaeus vanname i .  Real-time quantitative RT-PCR showed that AQP11 gene could be detected in all tested tissues of Eirocheir sinensis , with the highest expression level in intestine, followed by the brain, muscle and thoracic ganglion, and the lowest expression level in the hepatopancreas, gills and blood. In the intestinal, the expression of AQP11 was significantly lower at the intermolt stage (stages C) and premolt stage (stage D), significantly enhanced and reached the maximal level at the ecdysis stage (stage E). On the other hand, the expression of AQP11 gene in muscle showed low expression in the intermolt stage (stage C), and it was increased gradually at the premolt stage (stage D), significantly enhanced and reached the maximal level at the ecdysis stage (E stage), and then reaching the postmolt stage(AB stage) decline. In summary, our results indicate that AQP11 may play an important role in molting of Enirocheir sinensis.