Mouse aquaporin 10 gene (AQP10) is a pseudogene

Morinaga, Tsutomu; Nakakoshi, Masamichi; Hirao, Akira; Imai, Masashi; Ishibashi, Keiichiro

doi:10.1016/s0006-291x(02)00536-3

Cited by 81 publications

(57 citation statements)

References 16 publications

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“…AQP10 is an aqua-glyceropore, which is almost exclusively expressed in regions of the gastrointestinal tract in humans (Hatakeyama et al, 2001;Ishibashi et al, 2002). Its subcellular localization is controversial (Hatakeyama et al, 2001;Ishibashi et al, 2002;Li et al, 2005;Laforenza et al, 2010), and surprisingly, it is a pseudogene in mouse (Morinaga et al, 2002).…”

Section: Research Articlementioning

confidence: 99%

“…Its subcellular localization is controversial (Hatakeyama et al, 2001;Ishibashi et al, 2002;Li et al, 2005;Laforenza et al, 2010), and surprisingly, it is a pseudogene in mouse (Morinaga et al, 2002). The AQP10 protein was reported in the brush-border membrane of absorptive enterocytes of the upper villus Laforenza et al, 2010), whereas other authors have demonstrated the presence of two AQP10 isoforms, one located in gastroentero-pancreatic endocrine cells and another truncated form (named AQP10v), in capillary endothelial cells of villi (Li et al, 2005).…”

Section: Research Articlementioning

confidence: 99%

“…The AQP10 protein was reported in the brush-border membrane of absorptive enterocytes of the upper villus Laforenza et al, 2010), whereas other authors have demonstrated the presence of two AQP10 isoforms, one located in gastroentero-pancreatic endocrine cells and another truncated form (named AQP10v), in capillary endothelial cells of villi (Li et al, 2005). In humans, zebrafish and eel the ortholog is permeable to water, glycerol and urea (Ishibashi et al, 2002;MacIver et al, 2009;Tingaud-Sequeira et al, 2010). Recently, it was also found in human adipocytes, where it is co-expressed with two other glyceropores, AQP3 and AQP7 (Rodríguez et al, 2011;Laforenza et al, 2013), and may play a major role in glycerol metabolism.…”

Section: Research Articlementioning

confidence: 99%

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Aquaporin expression in the Japanese medaka (Oryzias latipes, Temminck & Schlegel) in FW and SW: challenging the paradigm for intestinal water transport?

Madsen

Bujak

Tipsmark

2014

Journal of Experimental Biology

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We investigated the salinity-dependent expression dynamics of seven aquaporin paralogs (aqp1a, aqp3a, aqp7, aqp8ab, aqp10a, aqp10b and aqp11a) in several tissues of euryhaline Japanese medaka (Oryzias latipes). All paralogs except aqp7 and aqp10a had a broad tissue distribution, and several were affected by salinity in both osmoregulatory and non-osmoregulatory tissues. In the intestine, aqp1a, aqp7, aqp8ab and aqp10a decreased upon seawater (SW) acclimation in both long-term acclimated fish and during 1-3 days of the transition period. In the gill, aqp3a was lower and aqp10a higher in SW than in freshwater (FW). In the kidney no aqps were affected by salinity. In the skin, aqp1a and aqp3a were lower in SW than in FW. In the liver, aqp8ab and aqp10a were lower in SW than in FW. Furthermore, six Na + ,K + -ATPase α-subunit isoform transcripts were analysed in the intestine but none showed a consistent response to salinity, suggesting that water transport is not regulated at this level. In contrast, mRNA of the Na + ,K + ,2Cl --cotransporter type-2 strongly increased in the intestine in SW compared with FW fish. Using custom-made antibodies, Aqp1a, Aqp8ab and Aqp10a were localized in the apical region of enterocytes of FW fish. Apical staining intensity strongly decreased, vanished or moved to subapical regions, when fish were acclimated to SW, supporting the lower mRNA expression in SW. Western blots confirmed the decrease in Aqp1a and Aqp10a in SW. The strong decrease in aquaporin expression in the intestine of SW fish is surprising, and challenges the paradigm for transepithelial intestinal water absorption in SW fishes.

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Section: Research Articlementioning

confidence: 99%

Section: Research Articlementioning

confidence: 99%

Section: Research Articlementioning

confidence: 99%

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Aquaporin expression in the Japanese medaka (Oryzias latipes, Temminck & Schlegel) in FW and SW: challenging the paradigm for intestinal water transport?

Madsen

Bujak

Tipsmark

2014

Journal of Experimental Biology

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“…Eleven aquaporins (AQP0 to AQP10) have been identified and functionally characterized in humans. We reported the most recent AQP, AQP10 (11,13). Their physiological importance is documented by the targeted disruption in mice (knockout mice) and by the discovery of humans and mice with nonfunctioning mutations.…”

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confidence: 99%

Disruption of Aquaporin-11 Produces Polycystic Kidneys following Vacuolization of the Proximal Tubule

Morishita

Matsuzaki

Hara‐Chikuma

et al. 2005

Molecular and Cellular Biology

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237

262

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Aquaporin-11 (AQP11) has been identified with unusual pore-forming NPA (asparagine-proline-alanine) boxes, but its function is unknown. We investigated its potential contribution to the kidney. Immunohistochemistry revealed that AQP11 was localized intracellularly in the proximal tubule. When AQP11 was transfected in CHO-K1 cells, it was localized in intracellular organelles. AQP11-null mice were generated; these mice exhibited vacuolization and cyst formation of the proximal tubule. AQP11-null mice were born normally but died before weaning due to advanced renal failure with polycystic kidneys, in which cysts occupied the whole cortex. Remarkably, cyst epithelia contained vacuoles. These vacuoles were present in the proximal tubules of newborn mice. In 3-week-old mice, these tubules contained multiple cysts. Primary cultured cells of the proximal tubule revealed an endosomal acidification defect in AQP11-null mice. These data demonstrate that AQP11 is essential for the proximal tubular function. AQP11-null mice are a novel model for polycystic kidney diseases and will provide a new mechanism for cystogenesis.Aquaporins (AQPs) are a family of membrane proteins that facilitate the transport of water and small solutes (8,15,21). They are distributed widely in nature from bacteria to animals. Eleven aquaporins (AQP0 to AQP10) have been identified and functionally characterized in humans. We reported the most recent AQP, AQP10 (11, 13). Their physiological importance is documented by the targeted disruption in mice (knockout mice) and by the discovery of humans and mice with nonfunctioning mutations. Of nine AQPs disrupted in mice and humans (AQP0 to AQP7 and AQP10), only AQP2-null mice die due to massive polyuria from nephrogenic diabetes insipidus (23). The milder phenotypes in AQP disruptions in general are surprising, since water is vital for organisms. Therefore, AQPs seem to be not critically essential for the survival of mammals but seem to be involved in the quality of their lives.The completion of human genome projects has revealed two more aquaporin-like genes, which we have deposited in GenBank under the names of AQPX1 and AQPX2 (9). They are renamed AQP11 and AQP12 with the approval of the Human Gene Nomenclature Committee. Rat AQP11 (AQPX1) is highly expressed in the testis and moderately expressed in the kidney, liver, and brain. On the other hand, rat AQP12 (AQPX2) is selectively expressed in the pancreas. They share similar genome structures with three exons, which are distinct from other AQPs: AQP0, AQP1, AQP2, AQP4, AQP5, and AQP6 have four exons; AQP3, AQP7, AQP8, AQP9, and AQP10 have six exons. In humans, AQP11 is mapped to chromosome 11q14 and AQP12 to chromosome 2q34-37, to which no diseases have been mapped. Moreover, we were not able to express them functionally in Xenopus oocytes. Therefore, their functions and physiological significance remain to be clarified.Previous AQPs have two highly conserved, short sequences named NPA (asparagine-proline-alanine) boxes. Each one of the NPA boxes has ...

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“…Only four mammalian AQP sequences have been identified as potential aquaglyceroporins, namely, Aqp3 (9, 18), Aqp7 (31), Aqp9 (5, 41), and Aqp10 (17, 34). However, murine Aqp10 was found to be a pseudogene (35). For this communication, we found that of the three functional aquaglyceroporins, only Aqp7 is expressed in the ␤ cells of pancreatic islets.…”

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confidence: 82%

Aquaporin 7 Is a β-Cell Protein and Regulator of Intraislet Glycerol Content and Glycerol Kinase Activity, β-Cell Mass, and Insulin Production and Secretion

Matsumura

Chang

Fujimiya³

et al. 2007

Molecular and Cellular Biology

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To investigate if intracellular glycerol content plays a role in the regulation of insulin secretion in pancreatic ␤ cells, we studied the expression of the glycerol channels, or aquaglyceroporins, encoded by the aquaporin 3 (Aqp3), Aqp7, and Aqp9 genes in mouse islets. We found expression of Aqp7 only, not that of Aqp3 or Aqp9, in the endocrine pancreas at both the mRNA (by reverse transcription-PCR) and protein (by immunohistochemistry) levels. Immunohistochemistry revealed a complete overlap between insulin and Aqp7 immunostaining in the pancreatic islet. Inactivation of Aqp7 by gene targeting produced viable and healthy mice. Aqp7 ؊/؊ mice harbored an increased intraislet glycerol concentration with a concomitant increase of the glycerol kinase transcript level and enzyme activity. The islet triglyceride content in the Aqp7 ؊/؊ mice was also increased compared to that in the Aqp7 ؉/؉ mice. Interestingly, Aqp7 ؊/؊ mice displayed reduced ␤-cell mass and insulin content but increased insulin-1 and insulin-2 mRNAs. The reduction of ␤-cell mass in Aqp7 ؊/؊ mice can be explained at least in part by a reduction in cell proliferation through protein kinase C and the c-myc cascade, with a reduction in the transcript levels of these two genes. Concomitantly, there was a decreased rate of apoptosis, as reflected by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling and caspase 3 and Bax expression in Aqp7 ؊/؊ mice. Compared with Aqp7 ؉/؉ islets, islets isolated from Aqp7mice secreted insulin at a higher rate under basal low-glucose conditions and on exposure to a high (450 mg/dl) glucose concentration. Aqp7 ؊/؊ mice exhibited normal fasting blood glucose levels but elevated blood insulin levels. Their plasma glucose response to an intraperitoneal (i.p.) glucose tolerance test was normal, but their plasma insulin concentrations were higher than those of wild-type mice during the 2-h test. An i.p. insulin tolerance test showed similar plasma glucose lowering in Aqp7 ؊/؊ and Aqp7 ؉/؉ mice, with no evidence of insulin resistance. In conclusion, we found that pancreatic ␤ cells express AQP7, which appears to be a key regulator of intraislet glycerol content as well as insulin production and secretion.Glucose is the most important nutrient that regulates insulin secretion (21). In addition to its key role in insulin secretion, plasma glucose also regulates ␤-cell mass; in insulin-resistant states, the ␤-cell mass increases to provide sufficient insulin to keep the plasma glucose concentration in check. Therefore, glucose appears to play dual roles as a stimulus both for acute insulin secretion and for a compensatory increase in ␤-cell mass (8). Unlike glucose, glycerol, a triose sugar, has no apparent effect on insulin secretion (37, 39), though a closely related metabolite, glyceraldehyde, has a potent effect (1, 2). One reason that glycerol does not function as a signal for insulin secretion is that it appears not to be metabolized by pancreatic ␤ cells (37). Induced overexpression of glycerol kina...

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Mouse aquaporin 10 gene (AQP10) is a pseudogene

Cited by 81 publications

References 16 publications

Aquaporin expression in the Japanese medaka (Oryzias latipes, Temminck & Schlegel) in FW and SW: challenging the paradigm for intestinal water transport?

Aquaporin expression in the Japanese medaka (Oryzias latipes, Temminck & Schlegel) in FW and SW: challenging the paradigm for intestinal water transport?

Disruption of Aquaporin-11 Produces Polycystic Kidneys following Vacuolization of the Proximal Tubule

Aquaporin 7 Is a β-Cell Protein and Regulator of Intraislet Glycerol Content and Glycerol Kinase Activity, β-Cell Mass, and Insulin Production and Secretion

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