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Molecular cloning and characterization of an aquaporin cDNA from salivary, lacrimal, and respiratory tissues
- Source :
- The Journal of biological chemistry. 270(4)
- Publication Year :
- 1995
-
Abstract
- The Aquaporin family of water channels plays a fundamental role in transmembrane water movements in numerous plant and animal tissues. Since the molecular pathway by which water is secreted by salivary glands is unknown, a cDNA was isolated from rat submandibular gland by homology cloning. Similar to other Aquaporins, the salivary cDNA encodes a 265-residue polypeptide with six putative transmembrane domains separated by five connecting loops (A-E); the NH2- and COOH-terminal halves of the polypeptide are sequence-related, and each contains the motif Asn-Pro-Ala. A mercurial-inhibition site is present in extracellular loop E, and cytoplasmic loop D contains a cAMP-protein kinase phosphorylation consensus. In vitro translation yielded a 27-kDa polypeptide, and expression of the cRNA in Xenopus oocytes conferred a 20-fold increase in osmotic water permeability (Pf) which was reversibly inhibited by 1 mM HgCl2. Northern analysis demonstrated a 1.6-kilobase mRNA in submandibular, parotid, and sublingual salivary glands, lacrimal gland, eye, trachea, and lung. In situ hybridization revealed a strong hybridization over the corneal epithelium in eye and over the secretory lobules in salivary glands. These studies have identified a new mammalian member of the Aquaporin water channel family (gene symbol AQP5) which is implicated in the generation of saliva, tears, and pulmonary secretions.
- Subjects :
- Saliva
DNA, Complementary
Xenopus
Molecular Sequence Data
Restriction Mapping
Submandibular Gland
Aquaporin
Lacrimal gland
In situ hybridization
Biology
Molecular cloning
Aquaporins
Kidney
Biochemistry
Ion Channels
Protein Structure, Secondary
Salivary Glands
RNA, Complementary
stomatognathic system
Complementary DNA
Lens, Crystalline
medicine
Animals
Amino Acid Sequence
RNA, Messenger
Cloning, Molecular
Molecular Biology
Lung
DNA Primers
Aquaporin 1
Base Sequence
Lacrimal Apparatus
Cell Biology
Blotting, Northern
Submandibular gland
Molecular biology
Rats
Trachea
Transmembrane domain
medicine.anatomical_structure
Organ Specificity
Protein Biosynthesis
Oocytes
Female
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 270
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- The Journal of biological chemistry
- Accession number :
- edsair.doi.dedup.....a5a4d71d9d17051ec86fbe0dfd4485db