Cloning and functional expression of rAOP9L a new member of aquaporin family from rat liver.
A new aquaporin was isolated from rat liver based on homology to known aquaporins. A 1408 bp cDNA was sequenced (designated rAQP9L) with a 885 bp open reading frame encoding a 295 amino acid hydrophobic protein. rAQP9L has the greatest amino-acid sequence identity with human AQP9 (75%) and a less homology with AQP3 (49%) and AQP7 (47%). Northern blot analysis indicated a 1.4-kb transcript expressed strongly in liver > testis > brain = lung. Expression of rAQP9L cRNA in Xenopus oocytes increased osmotic water permeability by 6-folds which was inhibited by 0.3 mM mercury chloride by 42%. rAQP9L also facilitated glycerol and urea transport by 2- and 5-folds, respectively. The large discrepancy of tissue distribution between hAQP9 and rAQP9L suggest that rAQP9L is a new aquaporin, which is involved in transport of urea as well as water in liver.
Ko
S B
SB
International Medicine II, Nagoya University School of Medicine, Japan.
Uchida
S
S
Naruse
S
S
Kuwahara
M
M
Ishibashi
K
K
Marumo
F
F
Hayakawa
T
T
Sasaki
S
S
D000595:Amino Acid Sequence; D000818:Animals; D020346:Aquaporins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D001692:Biological Transport; D003001:Cloning, Molecular; D008099:Liver / Q000201:enzymology*; D008627:Mercuric Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D009865:Oocytes / Q000201:enzymology; D012333:RNA, Messenger / Q000737:chemistry; D051381:Rats; D016415:Sequence Alignment; D014508:Urea / Q000378:metabolism; D014867:Water / Q000378:metabolism; D014981:Xenopus
C491637:Aqp9 protein, rat; D020346:Aquaporins; D012333:RNA, Messenger; D014867:Water; D008627:Mercuric Chloride; D014508:Urea