title: Expression analysis and molecular characterization of aquaporins in Rhodnius prolixus.
abstract: Aquaporins (AQPs) are water channels responsible for transport of water and, in some cases, transport of small solutes such as urea and glycerol across lipid bilayer membranes. Hematophagous insects, such as Rhodnius prolixus, ingest large volumes of fluid and must rapidly eliminate the excess of water and salts from the blood meal within the gut. In order to deal with this increase in body fluid volume, a hormone-controlled diuresis is activated, during which a high rate of water and salt absorption occurs across the anterior midgut, followed by secretion of water and salts by the Malpighian tubules (MTs). Previously, one member of the MIP family (major intrinsic protein that includes the AQP family) was identified in the MTs of R. prolixus, and named RpMIP. We have described here that the RpMIP gene has different variants, and is present in tissues other than MTs. In addition, we have characterized a new AQP (RhoprAQP1) found in different tissues of R. prolixus. The expression of these transcripts in unfed insects as well as blood fed insects was evaluated using real-time quantitative PCR. Molecular models of the predicted proteins were constructed and the characteristics of their pores evaluated. A yeast complementation assay was used to validate that the products of these transcripts were bona fide AQPs. Both RhoprAQP1 and RhoprMIP-A were capable of transporting water whereas RhoprMIP-A was also capable of transporting H2O2. Taken together, these analyses suggest that RhoprMIP is probably an aquaglyceroporin, while RhoprAQP1 appears to be a strict aquaporin that transports only water.
authors.affiliation: Department of Molecular Biology and Biotechnology, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: fernanda.staniscuaski@ufrgs.br.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Staniscuaski
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Paluzzi
authors.forename: Rafael
authors.initials: R
authors.lastname: Real-Guerra
authors.forename: Célia R
authors.initials: CR
authors.lastname: Carlini
authors.forename: Ian
authors.initials: I
authors.lastname: Orchard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051397:Aquaglyceroporins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051398:Aquaporin 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D008317:Malpighian Tubules / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D060888:Real-Time Polymerase Chain Reaction; D012239:Rhodnius / Q000737:chemistry* / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D017422:Sequence Analysis, DNA; D014867:Water / Q000378:metabolism
chemical_list: D051397:Aquaglyceroporins; D017931:DNA Primers; D018076:DNA, Complementary; D014867:Water; D051398:Aquaporin 1
keywords: Anterior midgut; Aquaglyceroporins; Insect; Malpighian tubules; Water; qPCR