A Novel Aquaporin 12-like Protein from : Characterization and Functional Analysis.

Aquaporins (AQPs), which are members of the major intrinsic protein (MIP) family, play an important role in the transport of water and other small, uncharged solutes across membranes. In this study, we identified gene encoding two aquaporin 12-like (AQP12L) proteins, and , from , a serious rice pest in Asia. Phylogenetic analysis indicated that AQP12L_V1 and AQP12L_V2 were grouped in a well-supported cluster that included other members of Lepidoptera. The two proteins are almost identical, except that AQP12L_V1 lacks 34 amino acids that are present in AQP12L_V2 at site 217. The qRT-PCR indicated that both and were expressed in heads, epidermis, foregut, midgut, and hindguts, with the highest level of expression in hindguts, heads, and epidermis. Expression of and was detected in all life stages and both sexes and was highest in first instar larvae and lowest in eggs. Expression of and was not significantly altered by exposure to brief changes in temperature. There were no significant differences in the third instar larvae, male and female pupae, and female adults in response to adverse humidity. However, the mRNA level of in the fifth instar larvae and in male adults was induced significantly by low humidity, respectively. Moreover, oocytes injected with cRNAs of AQP12L_V1 and AQP12L_V2 showed no significant changes in permeability to water, glycerol, trehalose, or urea. The two AQP12L variants likely localize to an intracellular location in and may respond to novel stimuli.