Dehydration-inducible changes in expression of two aquaporins in the sleeping chironomid, Polypedilum vanderplanki.
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.
Kikawada
Takahiro
T
Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634 Japan.
Saito
Ayako
A
Kanamori
Yasushi
Y
Fujita
Mika
M
Snigórska
Katarzyna
K
Watanabe
Masahiko
M
Okuda
Takashi
T
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
D020346:Aquaporins; D017931:DNA Primers; D018076:DNA, Complementary; D014867:Water