| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Pathology, Aquaporin (AQP) 5 gene was recently isolated from salivary gland
and identified as a member of the AQP family. The mRNA
expression and localization have been examined in several organs. The
present study was focused on elucidation of AQP5 expression and
localization in the eye, salivary gland, and lung in rat. RNase
protection assay confirmed intense expression of AQP5 mRNA in these
organs but negligible expression in other organs. To examine the mRNA expression sites in the eye, several portions were microdissected for
total RNA isolation. AQP5 mRNA was enriched in cornea but not in other
portions (retina, lens, iris/ciliary body, conjunctiva, or sclera).
AQP5 was selectively localized on the surface of corneal epithelium in
the eye by immunohistochemistry and immunoelectron microscopy using an
affinity-purified anti-AQP5 antibody. AQP5 was also localized on apical
membranes of acinar cells in the lacrimal gland and on the microvilli
protruding into intracellular secretory canaliculi of the serous
salivary gland. In the lung, apical membranes of type I pulmonary
epithelial cells were also immunostained with the antibody. These
findings suggest a role of AQP5 in water transport to prevent
dehydration or to secrete watery products in these tissues.
aquaporin; water channel; messenger ribonucleic acid expression; immunohistochemistry; immunoelectron microscopy
AQUAPORINS (AQP) are a family of water channels, which
are water-selective transporting proteins with homology to major
intrinsic protein (MIP) of lens (9). At present, 10 types of mammalian AQPs have been identified (13-15, 19-21, 33). AQP1 was the
first to be isolated from human erythrocytes and was then demonstrated to occur widely in fluid-transporting epithelia and endothelia, including kidney and other tissues (3, 6, 25, 27, 31). AQP2 is a water
channel that is exclusively present in collecting ducts in the kidney,
and the translocation of this water channel from intracellular vesicles
to the apical membranes is regulated by vasopressin (8, 23, 24, 35).
AQP3 gene was isolated from kidneys and characterized as transporting
water and small nonionic molecules such as urea and glycerol. AQP3 is
localized on the basolateral membrane of collecting duct cells in
kidneys and is found in the epithelial cells of digestive tract and in conjunctival epithelium in the eye (4, 7, 16, 22, 25). A
mercury-insensitive water channel, AQP4 was demonstrated to occur
abundantly in the brain and less abundantly in the eye, kidney, lung,
and intestine (7, 10, 18, 25, 26). AQP5 gene was cloned from salivary
gland cDNA (29). Northern blot analysis and in situ hybridization
showed AQP5 mRNA expression in the salivary gland, eye, lacrimal gland,
lung, and trachea (29). Immunocytochemical microscopy recently
demonstrated the presence of AQP5 on the apical membrane of salivary
gland, lung (11, 25), and lacrimal glands (17); however, localization of AQP5 in other organs, including eye, has not been examined. In the
present study, we employed RNase protection assay and immunostaining for detection of AQP5 mRNA expression and localization in the eye and
other systemic organs or tissues.
Tissues and RNA.
Systemic organs (cerebrum, cerebellum, eye, lacrimal gland,
submandibular salivary gland, heart, trachea, lung, liver, pancreas, small intestine, colon, spleen, lymph node, and kidney) were removed from adult Wistar-Kyoto rats. Eyes were segmentally dissected into
cornea, iris/ciliary body, lens, retina, conjunctiva, and sclera, and
the pulmonary bronchus was separated from the lung. A part of each
organ was fixed in methyl-Carnoy fixative for 16 h, dehydrated in
ethanol, and embedded in paraffin for immunohistochemistry. The eyes
were quick frozen in n-hexane at
PCR cloning of AQP5.
Nested, degenerate oligonucleotide primers employed in a previous study
(29) were synthesized: sense primers were MDU-1 (5'-STBGGNCAYRTBAGYGGNGCNCA-3') and MDU-2
(5'- RNase protection assay.
RNase protection assay was done as reported previously (5, 30). In
brief, 32P-labeled cRNA probes for
AQP5 mRNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA
were synthesized by in vitro transcription, using the linearized
plasmids inserted with AQP5 cDNA or GAPDH cDNA (114 bp, corresponding
to bp 673-787) as a housekeeping gene (5, 34). The specific
radioactivity of 32P-labeled cRNA
probes was adjusted to 1 × 105 cpm/µl each in hybridization
buffer (80% formamide, 40 mM PIPES, 0.4 M NaCl, and 1 mM EDTA). Ten
micrograms of total cellular RNA isolated from various tissues were
hybridized with the cRNA probes (1 × 105 cpm each) at 48°C for 16 h
in 10 µl of hybridization buffer. Unhybridized probes were digested
with RNase A (4.0 µg/ml) and RNase T1 (120 U/ml) mixture at 30°C
for 1 h, and then the RNases were digested with proteinase K (0.5 mg/ml) at 37°C for 30 min. After phenol-chloroform extraction, the
hybridized probes were precipitated with ethanol, denatured at 85°C
for 3 min, and electrophoresed on 6% polyacrylamide gels. The dried
gels were exposed to X-ray films (Fuji Photo Film, Kanagawa, Japan) for
16 h at Preparation of antibody.
An oligopeptide corresponding to the COOH-terminal 15 amino acids of
AQP5 (NH2-DHREERKKTIELTAH-COOH)
with an added cysteine at the COOH-terminus was
synthesized and conjugated with keyhole limpet hemocyanin as a carrier
protein. The conjugate of 1 mg was emulsified with complete Freund's
adjuvant and injected subcutaneously into New Zealand White rabbits
three times at 2-wk intervals. One week after the last injection, the
blood was collected to obtain antiserum (IBL, Fujioka, Japan).
Anti-AQP5 antibody was affinity-purified by using an AQP5 synthetic
peptide-conjugated column (Cellulofine, Seikagaku, Tokyo, Japan), and
the reactivity of the antibody to AQP5 was examined by
immunohistochemistry and Western blot analysis. The specificity of the
immunostaining of tissues was verified by blocking of the staining
after absorption of the antibody with the synthetic peptide. For
absorption, 50 µg of the synthetic peptide (~10 times excess to IgG
at molar ratio) was mixed with 1 ml of the affinity-purified anti-AQP5 antibody (0.5 mg IgG/ml) for 16 h at 4°C.
Western blotting.
Rat salivary gland, whole eye, and cornea were homogenized in 8 M urea
buffer [8 M urea, 50 mM Tris · HCl (pH 8.0), 1 mM dithiothreitol, and 1 mM EDTA] using a homogenizer (Polytron,
Kinematica, Lucerne, Switzerland). The homogenates were kept at room
temperature for 1 h and centrifuged for 30 min at 10,000 g at 4°C to remove cellular debris. Rat lung was
homogenized in 50 mM Tris · HCl buffer (pH 7.4) and
centrifuged for 10 min at 1,000 g to
remove cellular debris. The supernatant was recentrifuged for 10 min at
40,000 g at 4°C to obtain the
membrane fraction. Aliquots (~200 µg of total protein) of the
supernatants were diluted in the 2× sample buffer [100 mM
Tris · HCl (pH 6.8), 4% SDS, 10%
Immunohistochemistry and immunofluorescence microscopy.
The paraffin-embedded tissues were sectioned at a thickness of 4 µm,
and the sections were deparaffined with xylene and then rehydrated
through ethanol and distilled water. They were sequentially incubated
with 1) normal goat serum (1:20
dilution) for 30 min, 2)
affinity-purified anti-AQP5 antibody (1:3 dilution) or preimmune sera
(1:400 dilution) or affinity-purified anti-AQP5 peptide antibody absorbed with synthetic AQP5 (1:3 dilution) for 16 h, and
3) goat anti-rabbit immunoglobulins
conjugated to peroxidase-labeled dextran polymer (1:5 dilution) for 60 min. The peroxidase reaction products were colored with
diaminobenzidine.
ABSTRACT
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
INTRODUCTION
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
70°C for immunofluorescence microscopy. Small pieces of
cornea and salivary gland were fixed with
periodate-lysine-paraformaldehyde fixative for 4 h and embedded in
glycol methacrylate resin. Total cellular RNA was purified from these
organs and tissues by the acid guanidinium
thiocyanate-phenol-chloroform method (2).
GCHCAYNTNAAYCCHGYNGTNAC-3'); antisense primers were MDD-1
(5'-GCDGRNSCVARDGANCGNGCNGG-3') and MDD-2 (5'-
GDGCDGGRTTNATNSHNSMNCC-3'),
where 
and 
are
BamH I and EcoR I sites,
respectively. Rat salivary gland mRNA (1 µg) was reverse
transcribed to cDNA using random hexamer primers and reverse
transcriptase. The cDNA was amplified by PCR (30 cycles: 94°C, 1 min; 52°C, 1 min; and 72°C, 1 min) using 100 pmol of MDU-1 and
MDD-1. The product was reamplified with 100 pmol of MDU-2 and MDD-2,
and a band of ~300 bp of the PCR product was cut from an agarose gel
after gel electrophoresis. The purified cDNA was ligated into pGEM-3Z
vectors (Promega Japan, Tokyo, Japan) at the
EcoR
I/BamH I site. Rat AQP5 gene encoding bp 324-651 (328 bp) (29) was verified with an automated DNA sequencer (ABI 373A, Perkin-Elmer Japan, Urayasu, Japan), and the
plasmid was linearized with BamH I.
80°C.
-mercaptoethanol, and 20% glycerol], boiled for 5 min,
separated by electrophoresis on a 4-20% gradient
SDS-polyacrylamide gel, and transferred to a polyvinylidene difluoride
membrane. The membranes were preincubated for 2 h with blocking buffer
(10% nonfat milk, 0.05% Tween 20, and 0.5%
NaN3 in PBS) and incubated with
preimmune serum (diluted 1:2,000 in blocking buffer, ~50 µg IgG/ml)
or the affinity-purified antibody (diluted 1:10 in blocking buffer, 50 µg IgG/ml) at room temperature overnight. The membranes were then
washed in several changes of washing buffer (0.05% Tween 20 in PBS),
incubated for 1 h with goat anti-rabbit immunoglobulins conjugated to
peroxidase-labeled dextran polymer (DAKO, Carpinteria, CA), which had
been premixed with 0.02 volume of normal rat serum, and colored with
diaminobenzidine.
Immunogold electron microscopy. Ultrathin sections of resin-embedded tissues collected on nickel grid meshes were incubated with 5% nonfat milk for 60 min and subsequently with affinity-purified anti-AQP5 antibody (1:3 dilution) overnight. After several washes with PBS, the sections were incubated with gold (10 nm)-labeled anti-rabbit IgG (1:20; Aurion, Wagrningen, The Netherlands) for 2 h. These sections were gently washed in PBS several times, postfixed with 2.5% glutaraldehyde, and washed again with distilled water twice. They were then counterstained with 2% aqueous uranyl acetate and 1% lead citrate and examined under an electron microscope (Hitachi, Ibaragi, Japan).
| |
RESULTS |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
mRNA expression in systemic organs. AQP5 mRNA expression was demonstrated to be intense in RNA obtained from the salivary gland and less intense in whole eye and lung by RNase protection assay (Fig. 1A). No or negligible AQP5 mRNA expression was detected in other organs, including the trachea and bronchus of the respiratory system (Fig. 1B). In the fractions of eye, the expression was extremely high in cornea RNA and was negligible in other compartments (Fig. 1B).
|
Western blot analysis. The specificity or reactivity of the anti-AQP5 antibody was examined by Western blotting using solubilized salivary gland, lung, whole eye, and cornea samples. As shown in Fig. 2, ~27- and ~34-kDa bands were specifically stained in salivary gland and cornea samples with the affinity-purified anti-AQP5 antibody. The ~27-kDa band is presumed to be the nonglycosylated form of AQP5, and the ~34-kDa band is presumed to be the glycosylated form. These bands were less conspicuous in whole eye and lung samples.
|
Immunohistochemistry. Immunohistochemistry and immunofluorescence microscopy using the affinity-purified AQP5 antibody demonstrated apparent staining in the eye, salivary gland, lung, and lacrimal gland but no staining in other organs.
In the eyes, the immunofluorescence staining was exclusively localized at the corneal epithelium (Fig. 3, A and B). The staining was removed when the antibody was preincubated with the synthetic AQP5 peptide (Fig. 3C). Among the corneal epithelium cells, wing cells composing the intermediate layer were more intensely stained, circumscribing the outline of the cell membranes. The staining was less intense in the superficial cells and columnar basal cells. Immunoelectron microscopy clearly demonstrated that AQP5 was present on the cell membranes of corneal epithelial cells (Fig. 4A). No specific staining was observed in the corneal epithelium with preimmune sera.
|
|
| |
DISCUSSION |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
AQP5 mRNA expression in systemic organs has been examined by Northern blot and in situ hybridization (29) and by RNase protection assay (32). The expression of AQP5 mRNA in systemic organs observed in the present study was almost concordant with these previous studies (29, 32), in which AQP5 mRNA expression was demonstrated in the salivary gland, corneal epithelium, lacrimal gland, and lung. In contrast to these studies, AQP5 mRNA expression was not detected in the trachea by RNase protection assay in the present study. The reason for this discrepancy is unknown but may be explained by differences between the rat strains used (Wistar-Kyoto rats in the present study and Sprague-Dawley rats in the previous study). However, the finding of no AQP5 mRNA expression in trachea is also consistent with data obtained by the present immunohistochemistry and previous immunocytochemical (25) and in situ hybridization studies (29). Another possible explanation may be the presence of another AQP member in the trachea, the nucleotide sequence of which is closely homologous to that of AQP5 and is detected by cross-hybridization of Northern blotting.
The cellular and subcellular localization of AQP5 protein is informative for speculation on a role of AQP5 in water movement in these organs or tissues. A recent study clearly demonstrated localization of AQP5 at the apical side of the acinar cells in salivary gland and at the apical membrane of type I pulmonary epithelial cells in lung by use of a specific antibody against rat AQP5 (25). However, cellular and subcellular localization of AQP5 in the eye has not been revealed yet, although AQP5 mRNA expression is intense in the eye. To examine the AQP5 localization in rat eye and other organs, we prepared an antibody against rat AQP5 by immunizing rabbits with a synthetic peptide of rat AQP5 for immunohistochemistry, immunofluorescence, and immunoelectron microscopy. The antibody appeared to react to ~27- and ~34-kDa bands in protein samples prepared from cornea and salivary gland, which expressed AQP5 mRNA intensely. The ~27- and ~34-kDa bands are presumed to be the nonglycosylated and glycosylated forms of AQP5, respectively, as shown in other AQP family members (4, 24, 26, 27). Because no immunostaining was observed with this antibody in the kidney, where AQP1, AQP2, AQP3, and AQP4 have been demonstrated, the antibody was assumed to react to AQP5 specifically (data not shown). In addition, the anti-AQP5 antibody stained corneal epithelium in the eye, acinar cells in serous salivary gland, type I pulmonary epithelial cells, and acinar cells in the lacrimal gland, and the staining was removed when the preabsorbed antibody was used. These findings are concordant with AQP5 mRNA expression sites, indicating the reactivity and specificity of the AQP5 antibody to AQP5.
In the eye, several types of AQP have been demonstrated to be water channels: MIP (AQP0) in lens fiber (9); AQP1 in cornea, trabecular meshwork, canal of Schlemm, iris, ciliary body, and lens (28); AQP3 in conjunctival epithelium (7); and AQP4 in iris, ciliary body, and retinal nuclear layer (7, 10). The present study showed exclusive AQP5 mRNA expression in the cornea and negligible AQP5 mRNA expression in the other compartments of the eye. Immunoelectron microscopy clearly demonstrated that AQP5 was constitutively present on the cell membrane of corneal epithelial cells and on the microvilli of the intercellular canaliculi in salivary glands in the present study. The observations are consistent with the previous finding shown by in situ hybridization (29). Because AQP5 is phyrogenically close to AQP2 (29), AQP5 may be speculated to translocate in response to some stimuli, like AQP2 (23, 35). However, the ultrastructural findings demonstrated the presence of AQP5 on the cell membrane and its absence in the cytoplasm, suggesting that AQP5 is not reserved in the cytoplasm.
Corneal epithelium consists of three types of epithelial cells (superficial, wing, and basal cells), and AQP5 was demonstrated on the cell membranes of all these cells by immunohistochemistry and immunoelectron microscopy. The presence of water channel in corneal epithelium has been suggested by physiological data showing that unidirectional water permeability of frog corneal epithelium increased significantly when chloride ion was present (1, 12). Therefore, AQP5 is strongly presumed to play a role in the water permeability of the corneal epithelium, although dependency of AQP5 on chloride ion has not been elucidated. AQP1 is also present in cornea but is restricted to corneal endothelium (31); therefore, the corneal water permeability may not be accounted for by AQP1 alone. AQP1 likely provides the gate for water from the corneal stroma to the aqueous humor or vice versa, and AQP5 may play a pivotal role in water translocation through corneal epithelium. These observations suggest an integral role of AQP1 and AQP5 in the prevention of dehydration and the maintenance of transparency of cornea.
AQP5 was demonstrated to occur in the salivary gland in the present study, as previously shown (11, 25). However, the immunohistochemistry in the present study further clarified the exclusive localization of AQP5 in the apical membrane of serous gland cells but not of mucous gland cells. Furthermore, AQP5 was demonstrated by immunoelectron microscopy to be intensely expressed on the microvilli in the intercellular canaliculi of serous glands but not in the cytoplasm of the acinar cells. The serous glands are known to secrete water-rich fluid containing enzymatic proteins, whereas mucous glands secrete mainly mucin. Because the water-rich fluid is secreted in the intercellular canaliculi where AQP5 was abundantly present, it is reasonable to speculate that AQP5 plays an important role in the secretion. Concomitantly, the finding may indicate a possible presence of other AQP members in the basolateral membrane of serous gland cells, which makes it possible for water to translocate through these cells.
In lung, AQP5 mRNA expression was intense, and AQP5 was conspicuously localized in the type I pulmonary epithelial cells. The presence of AQP1 has been demonstrated in both the alveolar cells and capillary endothelial cells (6), suggesting a role of AQP1 in transalveolar water movement in the lung, primarily through the transcellular route under physiological conditions (6). AQP5 mRNA expression has been demonstrated on pulmonary walls by in situ hybridization (29) and on type I alveolar epithelial cells by immunohistochemistry (25). The present study confirmed the localization of AQP5 in the type I pulmonary epithelial cells, suggesting a role of AQP5 in transalveolar water movement in the lung that is the same as that of AQP1.
| |
ACKNOWLEDGEMENTS |
|---|
We thank Kan Yoshida and Masaaki Nameta for expert technical assistance.
| |
FOOTNOTES |
|---|
This work was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, Sports, and Culture (Japan).
Address for reprint requests: T. Yamamoto, Dept. of Pathology, Institute of Nephrology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
Received 7 July 1997; accepted in final form 22 June 1998.
| |
REFERENCES |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
1.
Candia, O. A.,
and
A. C. Zamudio.
Chloride-activated water permeability in the frog corneal epithelium.
J. Membr. Biol.
143:
259-266,
1995[Medline].
2.
Chomczynski, P.,
and
N. Sacchi.
Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction.
Anal. Biochem.
162:
156-159,
1987[Medline].
3.
Denker, B. M.,
B. L. Smith,
F. P. Kuhajda,
and
P. Agre.
Identification, purification, and partial characterization of a novel Mr 28,000 integral membrane protein from erythrocytes and renal tubules.
J. Biol. Chem.
263:
15634-15642,
1988
4.
Ecelbarger, C. A.,
J. Terris,
G. Frindt,
M. Echevarria,
D. Marples,
S. Nielsen,
and
M. A. Knepper.
Aquaporin-3 water channel localization and regulation in rat kidney.
Am. J. Physiol.
269 (Renal Fluid Electrolyte Physiol. 38):
F663-F672,
1995
5.
Feng, L.,
W. W. Tang,
D. J. Loakutoff,
and
C. B. Wilson.
Dysfunction of glomerular fibrinolysis in experimental antiglomerular basement membrane nephritis.
J. Am. Soc. Nephrol.
3:
1753-1764,
1993[Abstract].
6.
Folkesson, H. G.,
M. A. Matthay,
H. Hasegawa,
F. Kheradmand,
and
A. S. Verkman.
Transcellular water transport in lung alveolar epithelium through mercury-sensitive water channels.
Proc. Natl. Acad. Sci. USA
91:
4970-4974,
1994
7.
Frigeri, A.,
M. A. Gropper,
C. W. Turck,
and
A. S. Verkman.
Immunolocalization of the mercurial-insensitive water channel and glycerol intrinsic protein in epithelial cell plasma membranes.
Proc. Natl. Acad. Sci. USA
92:
4328-4331,
1995
8.
Fushimi, K.,
S. Uchida,
Y. Hara,
Y. Hirata,
F. Marumo,
and
S. Sasaki.
Cloning and expression of apical membrane water channel of rat kidney collecting tubule.
Nature
361:
549-552,
1993[Medline].
9.
Gorin, N. B.,
S. B. Yancey,
J. Cline,
J. P. Revel,
and
J. Horitz.
The major intrinsic protein (MIP) of the bovine lens fiber membrane.
Cell
39:
49-59,
1984[Medline].
10.
Hasegawa, H.,
T. Ma,
W. Skach,
M. A. Matthay,
and
A. S. Verkman.
Molecular cloning of a mercurial-insensitive water channel expressed in selected water-transporting tissues.
J. Biol. Chem.
269:
5497-5500,
1994
11.
He, X.,
C.-M. Tse,
M. Donowitz,
S. L. Alper,
S. E. Gabriel,
and
B. J. Baum.
Polarized distribution of key membrane transport proteins in the rat submandibular gland.
Pflügers Arch.
433:
260-268,
1997[Medline].
12.
Horwich, T.,
C. Ibarra,
P. Ford,
A. Zamudio,
M. Parisi,
and
O. A. Candia.
mRNA from frog corneal epithelium increases water permeability in Xenopus oocytes.
Invest. Ophthalmol. Vis. Sci.
36:
2772-2774,
1995
13.
Ishibashi, K.,
M. Kuwahara,
Y. Gu,
Y. Kageyama,
A. Tohsaka,
F. Marumo,
and
S. Sasaki.
Cloning and functional expression of a new water channel abundantly expressed in the testis also permeable to glycerol and urea.
J. Biol. Chem.
272:
20782-20786,
1997
14.
Ishibashi, K.,
M. Kuwahara,
Y. Gu,
Y. Tanaka,
F. Marumo,
and
S. Sasaki.
Cloning and functional expression of a new aquaporin (AQP9) abundantly expressed in the peripheral leukocytes permeable to water and urea, but not to glycerol.
Biochem. Biophys. Res. Commun.
244:
268-274,
1998[Medline].
15.
Ishibashi, K.,
M. Kuwahara,
Y. Kageyama,
A. Tohsaka,
F. Marumo,
and
S. Sasaki.
Cloning and functional expression of a new water channel abundantly expressed in the testis.
Biochem. Biophys. Res. Commun.
237:
714-718,
1997[Medline].
16.
Ishibashi, K.,
S. Sasaki,
K. Fushimi,
S. Uchida,
M. Kuwahara,
H. Saito,
T. Furukawa,
K. Nakajima,
Y. Yamaguchi,
T. Gojobari,
and
F. Marumo.
Molecular cloning and expression of a member of the aquaporin family with permeability to glycerol and urea in addition to water expressed at the basolateral membrane of kidney collecting duct cells.
Proc. Natl. Acad. Sci. USA
91:
6269-6273,
1994
17.
Ishida, N.,
S. Hirai,
and
S. Mita.
Immunolocalization of aquaporin homologs in mouse lacrimal glands.
Biochem. Biophys. Res. Commun.
238:
891-895,
1997[Medline].
18.
Jung, J. S.,
R. V. Bhat,
G. M. Preston,
W. B. Guggino,
J. M. Baraban,
and
P. Agre.
Molecular characterization of an aquaporin cDNA from brain: candidate osmoreceptor and regulator of water balance.
Proc. Natl. Acad. Sci. USA
91:
13052-13056,
1994
19.
King, L. S.,
and
P. Agre.
Pathophysiology of the aquaporin water channels.
Annu. Rev. Physiol.
58:
619-648,
1996[Medline].
20.
Knepper, M. A.
The aquaporin family of molecular water channels.
Proc. Natl. Acad. Sci. USA
91:
6255-6258,
1994
21.
Koyama, Y.,
T. Yamamoto,
D. Kondo,
H. Funaki,
E. Yaoita,
K. Kawasaki,
N. Sato,
K. Hatakeyama,
and
I. Kihara.
Molecular cloning of a new aquaporin from rat pancreas and liver.
J. Biol. Chem.
272:
30329-30333,
1997
22.
Ma, T.,
A. Frigeri,
H. Hasegawa,
and
A. S. Verkman.
Cloning of a water channel homolog expressed in brain meningeal cells and kidney collecting duct that functions as a stilbene-sensitive glycerol transporter.
J. Biol. Chem.
269:
21845-21849,
1994
23.
Nielsen, S.,
C. L. Chou,
D. Marples,
E. I. Christensen,
B. K. Kishore,
and
M. A. Knepper.
Vasopressin increases water permeability of kidney collecting duct by inducing translocation of aquaporin-CD water channels to plasma membrane.
Proc. Natl. Acad. Sci. USA
92:
1013-1017,
1995
24.
Nielsen, S.,
S. R. DiGiovanni,
E. I. Christensen,
M. A. Knepper,
and
H. W. Harris.
Cellular and subcellular immunolocalization of vasopressin-regulated water channel in rat kidney.
Proc. Natl. Acad. Sci. USA
90:
11663-11667,
1993
25.
Nielsen, S.,
L. S. King,
B. M. Christensen,
and
P. Agre.
Aquaporins in complex tissues. II. Subcellular distribution in respiratory and glandular tissues of rat.
Am. J. Physiol.
273 (Cell Physiol. 42):
C1549-C1561,
1997.
26.
Nielsen, S.,
E. A. Nagelhus,
M. Amiry-Moghaddam,
C. Bourque,
P. Agre,
and
O. P. Pettersen.
Specialized membrane domains for water transport in glial cells: high-resolution immunogold cytochemistry of aquaporin-4 in rat brain.
J. Neurosci.
17:
171-180,
1997
27.
Nielsen, S.,
B. L. Smith,
E. I. Christensen,
M. A. Knepper,
and
P. Agre.
CHIP28 water channels are localized in constitutively water-permeable segments of nephron.
J. Cell Biol.
120:
371-383,
1993
28.
Preston, G. M.,
T. P. Carroll,
W. B. Guggino,
and
P. Agre.
Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein.
Science
256:
385-387,
1992
29.
Raina, S.,
G. M. Preston,
W. B. Guggino,
and
P. Agre.
Molecular cloning and characterization of an aquaporin cDNA from salivary, lacrimal, and respiratory tissues.
J. Biol. Chem.
270:
1908-1912,
1995
30.
Sambrook, J.,
F. F. Fritsch,
and
T. Maniatis.
Extraction, purification, and analysis of messenger RNA from eukaryotic cells.
In: Molecular Cloning. A Laboratory Manual (2nd ed.), edited by J. Sambrook,
F. F. Fritsch,
and T. Maniatis. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory, 1989, p. 71-78.
31.
Stamer, W. D.,
R. W. Snyder,
B. L. Smith,
P. Agre,
and
J. W. Regan.
Localization of aquaporin CHIP in the human eye: implications in the pathogenesis of glaucoma and other disorders of ocular fluid balance.
Invest. Ophthalmol. Vis. Sci.
35:
3867-3872,
1994
32.
Umenishi, F.,
A. S. Verkman,
and
M. A. Gropper.
Quantitative analysis of aquaporin mRNA expression in rat tissues by RNase protection assay.
DNA Cell Biol.
15:
475-480,
1996[Medline].
33.
Verkman, A. S.,
A. N. van Hoek,
T. Ma,
A. Frigeri,
W. R. Skach,
A. Mitra,
B. K. Tamarappoo,
and
J. Farinas.
Water transport across mammalian cell membranes.
Am. J. Physiol.
270 (Cell Physiol. 39):
C12-C30,
1996
34.
Yamamoto, T.,
S. Sasaki,
K. Fushimi,
K. Ishibashi,
E. Yaoita,
K. Kawasaki,
H. Fujinaka,
F. Marumo,
and
I. Kihara.
Expression of AQP family in rat kidneys during development and maturation.
Am. J. Physiol.
272 (Renal Physiol. 41):
F198-F204,
1997
35.
Yamamoto, T.,
S. Sasaki,
K. Fushimi,
K. Ishibashi,
E. Yaoita,
K. Kawasaki,
F. Marumo,
and
I. Kihara.
Vasopressin increases AQP-CD water channel in apical membrane of collecting duct cells in Brattleboro rats.
Am. J. Physiol.
268 (Cell Physiol. 37):
C1546-C1551,
1995
This article has been cited by other articles:
|
|
 |
|
  V. Gresz, T.-H. Kwon, H. Gong, P. Agre, M. C. Steward, L. S. King, and S. Nielsen Immunolocalization of AQP-5 in rat parotid and submandibular salivary glands after stimulation or inhibition of secretion in vivo Am J Physiol Gastrointest Liver Physiol, July 1, 2004; 287(1): G151 - G161. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Borok and A. S. Verkman Lung Edema Clearance: 20 Years of Progress: Invited Review: Role of aquaporin water channels in fluid transport in lung and airways J Appl Physiol, December 1, 2002; 93(6): 2199 - 2206. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. B. H. Ko, S. Naruse, M. Kitagawa, H. Ishiguro, S. Furuya, N. Mizuno, Y. Wang, T. Yoshikawa, A. Suzuki, S. Shimano, et al. Aquaporins in rat pancreatic interlobular ducts Am J Physiol Gastrointest Liver Physiol, February 1, 2002; 282(2): G324 - G331. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Lange Role of microvillar cell surfaces in the regulation of glucose uptake and organization of energy metabolism Am J Physiol Cell Physiol, January 1, 2002; 282(1): C1 - C26. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. D. CRANDALL and M. A. MATTHAY Alveolar Epithelial Transport . Basic Science to Clinical Medicine Am. J. Respir. Crit. Care Med., March 15, 2001; 163(4): 1021 - 1029. [Full Text]
|
|
|
|
 |
|
 S. M. Kreda, M. C. Gynn, D. A. Fenstermacher, R. C. Boucher, and S. E. Gabriel Expression and Localization of Epithelial Aquaporins in the Adult Human Lung Am. J. Respir. Cell Mol. Biol., March 1, 2001; 24(3): 224 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Verkman, M. A. Matthay, and Y. Song Aquaporin water channels and lung physiology Am J Physiol Lung Cell Mol Physiol, May 1, 2000; 278(5): L867 - L879. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. I. Ramirez, U.-I. Chung, and M. C. Williams Aquaporin-5 Expression, but Not Other Peripheral Lung Marker Genes, Is Reduced in PTH/PTHrP Receptor Null Mutant Fetal Mice Am. J. Respir. Cell Mol. Biol., March 1, 2000; 22(3): 367 - 372. [Abstract] [Full Text]
|
|
|
|
 |
|
 T. Ma, Y. Song, A. Gillespie, E. J. Carlson, C. J. Epstein, and A. S. Verkman Defective Secretion of Saliva in Transgenic Mice Lacking Aquaporin-5 Water Channels J. Biol. Chem., July 16, 1999; 274(29): 20071 - 20074. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Koyama, T. Yamamoto, T. Tani, K. Nihei, D. Kondo, H. Funaki, E. Yaoita, K. Kawasaki, N. Sato, K. Hatakeyama, et al. Expression and localization of aquaporins in rat gastrointestinal tract Am J Physiol Cell Physiol, March 1, 1999; 276(3): C621 - C627. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
