Partial table of contents: SYSTEMATICS, PHYLOGENY, AND DATABASES. Biological Databases on the Internet (J. Blake & C. Bult). Molecular Approaches and Growth Phylogenetic Biology (W. Maddison). POPULATION STRUCTURE MOLECULAR MARKERS. Macrospatial Genetic Structure Speciation in Marine Taxa with High Dispersal Abilities (S. Palumbi). to Study Invasions Geller). PCR--Based Cloning Across Large Taxonomic Distances Polymorphism Detection: MHC as a Case Potts). CLASSIC PROBLEMS IN THE EVOLUTION OF...

In the renal collecting duct, vasopressin increases osmotic water permeability (<i>P</i> _f) by triggering trafficking of aquaporin-2 vesicles to apical plasma membrane. We investigated role vasopressin-induced intracellular Ca²⁺ mobilization in this process. isolated inner medullary ducts (IMCDs), (0.1 nm) and 8-(4-chlorophenylthio)-cAMP mm) elicited marked [Ca²⁺]_i (fluo-4). Vasopressin-induced was completely blocked preloading with chelator BAPTA....

Organisms, almost universally, adapt to hyperosmotic stress through increased accumulation of organic osmolytes but the molecular mechanisms have only begun be addressed. Among mammalian tissues, renal medullary cells are uniquely exposed extreme stress. Sorbitol, synthesized aldose reductase, is a predominant osmolyte induced under conditions in cells. Using rabbit cell line, we originally demonstrated that induces transcription reductase gene. Recently, cloned gene, characterized its...

Hypertonicity-induced binding of the transcription factor TonEBP/OREBP to its cognate DNA element, ORE/TonE, is associated with increased several osmotically regulated genes. Previously, it was found that hypertonicity rapidly causes nuclear translocation and phosphorylation and, more slowly, increases abundance. Also, C terminus contain a transactivation domain (TAD). We have now tested for tonicity dependence TAD activity 983 C-terminal amino acids TonEBP/OREBP. HepG2 cells were...

Acute hypertonicity causes cell cycle delay and apoptosis in mouse renal inner medullary collecting duct cells (mIMCD3) increases GADD45 expression. Because the tumor suppressor protein p53 may be involved these effects, we have investigated role of mIMCD3 response to hyperosmotic stress. elevation osmolality with NaCl addition from control level 320 mosmol/kg 500–600 greatly increased levels total Ser¹⁵-phosphorylated within 15 min. However, similar urea did not increase levels....

High NaCl activates the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP), resulting in increased of several protective genes, including glycine betaine/gamma-aminobutyric acid transporter (BGT1). damages DNA, and DNA damage ataxia telangiectasia mutated (ATM) kinase through autophosphorylation on Ser-1981. TonEBP/OREBP contains ATM consensus phosphorylation sites at Ser-1197, Ser-1247, Ser-1367. The present studies test whether is...

Elevated temperature rapidly increases expression of genes for heat shock proteins (HSP), including HSP-70. The response is presumably triggered by denaturation cell and helps in their renaturation. Hypertonicity may also denature proteins, but the protective response, which accumulation compatible organic osmolytes [including betaine inositol Madin-Darby canine kidney (MDCK) cells], apparently differs slow. Recently, hypertonicity was found to increase HSP-70 MDCK cells, a proposed provide...

In yeast glycerol-3-phosphate dehydrogenase 1 is essential for synthesis of the osmoprotectant glycerol and osmotically regulated via high osmolarity (HOG1) kinase pathway. Homologous protein kinases, p38, stress-activated kinase/Jun N-terminal (SAPK/JNK) are hyperosmotically activated in some mammalian cell lines complement HOG1 yeast. present study we asked whether p38 or SAPK/JNK signal sorbitol rabbit renal medullary cells (PAP-HT25), analogous to system Sorbitol catalyzed by aldose...

Cells generally adapt to long-term hyperosmolality by accumulating compatible organic osmolytes, thereby helping normalize both volume and intracellular inorganic ion concentration. When osmolytes are accumulated, as in renal inner medullary cells, it is the sum of their concentrations that theoretically important. In effect, when one osmolyte rises, others fall maintain approximately constant. The present study addresses mechanism controlling betaine accumulation. Hypertonicity induces...

Glycerophosphocholine (GPC) is an abundant osmoprotective renal medullary organic osmolyte. We previously found that its synthesis from phosphatidylcholine catalyzed by tonicity-regulated activity of the phospholipase B, neuropathy target esterase. also degradation glycerophosphocholine phosphodiesterase (GPC-PDE) and elevating osmolality 300 to 500 mosmol/kg adding NaCl or urea, inhibits GPC-PDE activity, which contributes resultant increase GPC. In present studies we identify GDPD5...

Hypertonicity-induced increase in activity of the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP) protects renal cells by increasing genes, including those involved increased accumulation organic osmolytes. We previously showed that hypertonicity increases transactivating TonEBP/OREBP. Assay with a binary GAL4 transactivation system 984 C-terminal amino acids TonEBP/OREBP (amino 548–1531) contain tonicity-dependent domain (TAD). Also,...

Diverse organisms accumulate organic osmolytes to adapt hyperosmotic stress. The molecular basis of eukaryotic gene osmoregulation remains obscure. Aldose reductase [AR; alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21], which catalyzes the conversion glucose sorbitol (an osmolyte), is induced in renal medullary cells under conditions. Elevated extracellular NaCl increases AR mRNA transcription PAP-HT25 cells, a cell line derived from rabbit papilla. We have cloned and characterized determine...

High NaCl causes DNA double-strand breaks and activates the transcription factor, TonEBP/OREBP, resulting in increased of several protective genes, including those involved accumulation compatible organic osmolytes. Several kinases are known to contribute signaling activation ATM, which is a member phosphatidylinositol 3-kinase (PI3K)-like kinase family activated by breaks. The purpose present studies was investigate possible role PI3K Class IA (PI3K-IA). We found that high increases PI3K-IA...

High NaCl activates the transcription factor nuclear of activated T cells 5 (NFAT5), leading to increased osmoprotective target genes. Kinases PKA, PI3K, AKT1, and p38α were known contribute high NaCl-induced increase NFAT5 activity. We now identify another kinase, GSK-3β. siRNA-mediated knock-down GSK-3β increases transcriptional transactivating activities without affecting localization or protein expression. phosphorylation GSK-3β-S9, which inhibits In GSK-3β-null mouse embryonic...

Hypertonicity increases mRNA and protein abundance of the transcription factor tonicity-responsive enhancer/osmotic response element binding (TonEBP/OREBP), contributing to increased downstream osmoprotective genes. Previously, this was attributed TonEBP/OREBP because no change found in its stability. However, there is direct evidence for transcription, 3'-untranslated region (UTR) contains numerous adenylate/uridylate-rich elements, which can modulate RNA Therefore, we have reinvestigated...

Sorbitol accumulates in renal medullary cells by synthesis from glucose a reaction catalyzed aldose reductase. Medullary sodium and urea are high vary with urinary concentration. varies similarly, consistent its role as compatible intracellular organic osmolyte. We measured sodium, urea, sorbitol, reductase (protein activity), mRNA rats treated to change urea. In untreated Brattleboro all measurements were low increased after 7 days of treatment arginine vasopressin. contrast, when normal...

The signaling pathways leading to high NaCl-induced activation of the transcription factor tonicity-responsive enhancer binding protein/osmotic response element protein (TonEBP/OREBP) remain incompletely understood. High NaCl has been reported produce oxidative stress. Reactive oxygen species (ROS), which are a component stress, contribute regulation factors. present study was undertaken test whether increase in ROS contributes tonicity-dependent TonEBP/OREBP. Human embryonic kidney 293...

Pax2 is a transcription factor that crucial for kidney development, and it also expressed in the normal adult kidney, where its physiological function unknown. In present study, we find by cDNA microarray analysis expression second-passage mouse inner-medullary epithelial cells increased high NaCl concentration, which significant because levels are normally inner medulla vivo , varies with urinary concentration. Furthermore, concentration increases mRNA protein medullary collecting duct...

Separate reports that hypertonicity activates p38 via a Rac1–OSM–MEKK3–MKK3–p38 pathway and p38α contributes to activation of TonEBP/OREBP led us the hypothesis Rac1 might activate p38. The present studies examine possibility. High NaCl is hypertonic. We find siRNA knockdown reduces high NaCl-induced increase transcriptional activity (by reducing its transactivating but not nuclear localization). Similarly, osmosensing scaffold for MEKK3 (OSM) also NaCl-dependent activities. Simultaneous OSM...

TonEBP is a transcription factor that, when activated by hypertonicity, increases of genes, including those involved in organic osmolyte accumulation. Surprisingly, it expressed virtually all tissues, many never normally exposed to hypertonicity. We measured mRNA (real-time PCR) and protein (Western blot analysis) tissues control (plasma osmolality 294 +/- 1 mosmol/kgH2O) hyposmotic (dDAVP infusion plus water loading for 3 days, 241 2 rats test whether the ubiquitous expression osmotically...

Hypertonicity activates the transcription factor tonicity-responsive enhancer/osmotic response element binding protein (TonEBP/OREBP), resulting in increased expression of genes involved osmoprotective accumulation organic osmolytes, including glycine betaine, and heat shock proteins. Our previous studies showed that high NaCl increases reactive oxygen species (ROS), which contribute to activation TonEBP/OREBP. Mitochondria are a major source ROS. The purpose present study was examine...

Glycerophosphocholine (GPC) is an osmoprotective compatible and counteracting organic osmolyte that accumulates in renal inner medullary cells response to high NaCl urea. We previously found increases GPC [Madin-Darby canine kidney (MDCK)] cells. The derived from phosphatidylcholine, catalyzed by a phospholipase was not identified at time. Neuropathy target esterase (NTE) recently shown be B catalyzes production of phosphatidylcholine. purpose the present study test whether NTE contributes...

When activated by high NaCl, tonicity-responsive enhancer–binding protein/osmotic response element–binding protein (TonEBP/OREBP) increases transcription of osmoprotective genes. High NaCl activates TonEBP/OREBP increasing its phosphorylation, nuclear localization, and transactivating activity. In HEK293 cells, mass spectrometry shows phosphorylation TonEBP/OREBP-S120, -S134, -T135, -S155. those residues are individually mutated to alanine, localization is greater for S155A, less S134A...