title: Identification and functional characterization of an ovarian aquaporin from the cockroach Blattella germanica L. (Dictyoptera, Blattellidae).
abstract: Aquaporins (AQPs) are membrane proteins that form water channels, allowing rapid movement of water across cell membranes. AQPs have been reported in species of all life kingdoms and in almost all tissues, but little is known about them in insects. Our purpose was to explore the occurrence of AQPs in the ovary of the phylogenetically basal insect Blattella germanica (L.) and to study their possible role in fluid homeostasis during oogenesis. We isolated an ovarian AQP from B. germanica (BgAQP) that has a deduced amino acid sequence showing six potential transmembrane domains, two NPA motifs and an ar/R constriction region, which are typical features of the AQP family. Phylogenetic analyses indicated that BgAQP belongs to the PRIP group of insect AQPs, previously suggested to be water specific. However, ectopic expression of BgAQP in Xenopus laevis oocytes demonstrated that this AQP transports water and modest amounts of urea, but not glycerol, which suggests that the PRIP group of insect AQPs may have heterogeneous solute preferences. BgAQP was shown to be highly expressed in the ovary, followed by the fat body and muscle tissues, but water stress did not significantly modify the ovarian expression levels. RNA interference (RNAi) reduced BgAQP mRNA levels in the ovary but the oocytes developed normally. The absence of an apparent ovarian phenotype after BgAQP RNAi suggests that other functionally redundant AQPs that were not silenced in our experiments might exist in the ovary of B. germanica.
authors: Institut de Biologia Evolutiva (CSIC-UPF) and LINC-Global, Passeig Maryítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors: Alba
authors: A
authors: Herraiz
authors: François
authors: F
authors: Chauvigné
authors: Joan
authors: J
authors: Cerdà
authors: Xavier
authors: X
authors: Bellés
authors: Maria-Dolors
authors: MD
authors: Piulachs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D020048:Blattellidae / Q000235:genetics* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005990:Glycerol / Q000378:metabolism; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000502:physiology*; D010053:Ovary / Q000378:metabolism*; D010802:Phylogeny; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014508:Urea / Q000378:metabolism; D014867:Water / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D020346:Aquaporins; D017931:DNA Primers; D014867:Water; D014508:Urea; D005990:Glycerol