The human Aquaporin-5 gene. Molecular characterization and chromosomal localization.
The cDNA for the fifth mammalian aquaporin (AQP5) was isolated from rat, and expression was demonstrated in rat salivary and lacrimal glands, cornea, and lung (Raina, S., Preston, G. M., Guggino, W. B., and Agre, P. (1995) J. Biol. Chem. 270, 1908-1912). Here we report the isolation and characterization of the human AQP5 cDNA and gene. The AQP5 cDNA from a human submaxillary gland library contains a 795-base pair open reading frame encoding a 265-amino acid protein. The deduced amino acid sequences of human and rat AQP5 are 91% identical with 6 substitutions in the 22-amino acid COOH-terminal domain. Expression of human AQP5 in Xenopus oocytes conferred mercurial-sensitive osmotic water permeability (Pf) equivalent to other aquaporins. The human AQP5 structural gene resides within a 7. 4-kilobase SalI-EcoRI fragment with four exons corresponding to amino acids 1-121, 122-176, 177-204, and 205-265 separated by introns of 1.2, 0.5, and 0.9 kilobases. A transcription initiation site was identified 518 base pairs upstream of the initiating methionine. Genomic Southern analysis indicated that AQP5 is a single copy gene which localized to human chromosome 12q13; this coincides with the chromosomal locations of the homologous human genes MIP and AQP2, thus confirming 12q13 as the site of an aquaporin gene cluster. The mouse gene localized to distal chromosome 15. This information may permit molecular characterization of AQP5 expression during normal development and in clinical disorders.
Lee
M D
MD
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore Maryland 21205-2185, USA.
Bhakta
K Y
KY
Raina
S
S
Yonescu
R
R
Griffin
C A
CA
Copeland
N G
NG
Gilbert
D J
DJ
Jenkins
N A
NA
Preston
G M
GM
Agre
P
P
D000595:Amino Acid Sequence; D000818:Animals; D051402:Aquaporin 5; D020346:Aquaporins; D001483:Base Sequence; D002874:Chromosome Mapping; D002881:Chromosomes, Human, Pair 12; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D005796:Genes; D006801:Humans; D007438:Introns; D007473:Ion Channels / Q000235:genetics*; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051381:Rats; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014882:Water-Electrolyte Balance
C496036:AQP5 protein, human; C496038:Aqp5 protein, mouse; C496040:Aqp5 protein, rat; D051402:Aquaporin 5; D020346:Aquaporins; D017931:DNA Primers; D018076:DNA, Complementary; D007473:Ion Channels; D008565:Membrane Proteins