title: Dehydration-inducible changes in expression of two aquaporins in the sleeping chironomid, Polypedilum vanderplanki.
abstract: Aquaporin, AQP, is a channel protein that allows water to permeate across cell membranes. Larvae of the sleeping chironomid, Polypedilum vanderplanki, can withstand complete dehydration by entering anhydrobiosis, a state of suspended animation; however, the mechanism by which water flows out of the larval body during dehydration is still unclear. We isolated two cDNAs (PvAqp1 and PvAqp2) encoding water-selective aquaporins from the chironomid. When expressed in Xenopus oocytes, PvAQP1 and PvAQP2 facilitated permeation of water but not glycerol. Northern blots and in situ hybridization showed that expression of PvAqp1 was dehydration-inducible and ubiquitous whereas that of PvAqp2 was dehydration-repressive and fat body-specific. These data suggest distinct roles for these aquaporins in P. vanderplanki, i.e., PvAqp2 controls water homeostasis of fat body during normal conditions and PvAqp1 is involved in the removal of water during induction of anhydrobiosis.
authors: Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634 Japan.
authors: Takahiro
authors: T
authors: Kikawada
authors: Ayako
authors: A
authors: Saito
authors: Yasushi
authors: Y
authors: Kanamori
authors: Mika
authors: M
authors: Fujita
authors: Katarzyna
authors: K
authors: Snigórska
authors: Masahiko
authors: M
authors: Watanabe
authors: Takashi
authors: T
authors: Okuda
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020346:Aquaporins / Q000235:genetics*; D001483:Base Sequence; D002683:Chironomidae / Q000235:genetics*; D017931:DNA Primers; D018076:DNA, Complementary; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D014867:Water / Q000737:chemistry*; D014981:Xenopus
chemical_list: D020346:Aquaporins; D017931:DNA Primers; D018076:DNA, Complementary; D014867:Water