Occludin and hydromineral balance in Xenopus laevis.
نویسندگان
چکیده
To investigate the response of the tight junction (TJ) protein occludin to environmental change in an anuran amphibian, we examined occludin tissue distribution, immunolocalization and alterations in mRNA expression in African clawed frogs (Xenopus laevis) acclimated to brackish water (BW) conditions (from freshwater to 2 per thousand, 5 per thousand or 10 per thousand salt water). Occludin mRNA is widely expressed in Xenopus and is abundant in tissues involved in regulating salt and water balance, such as the gastrointestinal (GI) tract, kidney and urinary bladder. Immunohistochemical analyses revealed strong occludin immunolabelling in the apicolateral region of epithelia lining the GI tract and mRNA expression increased along the longitudinal axis of the gut. In kidney tissue, occludin was differentially expressed on the luminal side of the nephron tubule, appearing in the distal tubules and collecting ducts only. In response to BW acclimation, Xenopus exhibited a significant loss of tissue water as well as salinity-dependent elevations in serum osmolality as a result of increased urea levels followed by elevated serum Na(+) and Cl(-) levels. Tissue-specific alterations in the ionomotive enzyme Na(+),K(+)-ATPase were also observed in Xenopus in response to BW acclimation. Most notably, Na(+),K(+)-ATPase activity in the rectum increased in response to elevated environmental salt concentrations while renal activity decreased. Furthermore, acclimation to BW caused tissue-specific and salinity-dependent alterations in occludin mRNA expression within select Xenopus osmoregulatory organs. Taken together, these studies suggest that alterations in occludin, in conjunction with active transport processes, may contribute to amphibian hydromineral homeostasis during environmental change.
منابع مشابه
The S362A mutation block ROMK2 (Kir1.1b) endocytosis in Xenopus laevis oocyte membrane .
Abstract The S362A mutation block ROMK2 (Kir1.1b) endocytosis in Xenopus laevis oocyte membrane . Saeed Hajihashemi1 , 1-Assistant professor, PhD in Physiology, Department of Physiology, School of Medical science, Arak University of Medical Sciences. Introduction: ROMK channel is localized on the apical membrane of the nephron. Recent studies suggest that endocytosis of ROMK chan...
متن کاملOccludin immunolocalization and protein expression in goldfish.
Tight junctions (TJs) are an integral component of models illustrating ion transport mechanisms across fish epithelia; however, little is known about TJ proteins in fishes. Using immunohistochemical methods and Western blot analysis, we examined the localization and expression of occludin, a transmembrane TJ protein, in goldfish tissues. In goldfish gills, discontinuous occludin immunostaining ...
متن کاملExpression of hsp90 Alpha and hsp90 Beta during Xenopus laevis Embryonic Development
Background: Members of the eukaryotic Hsp90 family function as important molecular chaperones in the assembly, folding and activation of cellular signaling in development. Two hsp90 genes, hsp90 alpha and hsp90 beta, have been identified in fish and homeothermic vertebrates but not in poikilothermic vertebrates. In the present study, the expression of hsp90 alpha and hsp90 beta genes in Xenopus...
متن کاملIntegrin Linked Kinase (X-ILK) Function during Embryonic Development and within Adult Tissues of Xenopus laevis
Integrin linked kinase (ILK) is a serine/threonine protein kinase implicated in the phosphatidylinositol 3’kinase (PI3’K) pathway. Integrin linked kinase has been investigated in different organisms such as mammalian systems (human, mice, rat), insects (Drosophila) and nematodes (Cenorhabditis elegans), however to date little data regarding ILK research on amphibians has been reported. In...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of experimental biology
دوره 212 Pt 2 شماره
صفحات -
تاریخ انتشار 2009