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951.
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The NEMO mutation creating the most-upstream premature stop codon is hypomorphic because of a reinitiation of translation
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Puel A Reichenbach J Bustamante J Ku CL Feinberg J Döffinger R Bonnet M Filipe-Santos O de Beaucoudrey L Durandy A Horneff G Novelli F Wahn V Smahi A Israel A Niehues T Casanova JL 《American journal of human genetics》2006,78(4):691-701
Amorphic mutations in the NF- kappa B essential modulator (NEMO) cause X-dominant incontinentia pigmenti, which is lethal in males in utero, whereas hypomorphic mutations cause X-recessive anhidrotic ectodermal dysplasia with immunodeficiency, a complex developmental disorder and life-threatening primary immunodeficiency. We characterized the NEMO mutation 110_111insC, which creates the most-upstream premature translation termination codon (at codon position 49) of any known NEMO mutation. Surprisingly, this mutation is associated with a pure immunodeficiency. We solve this paradox by showing that a Kozakian methionine codon located immediately downstream from the insertion allows the reinitiation of translation. The residual production of an NH(2)-truncated NEMO protein was sufficient for normal fetal development and for the subsequent normal development of skin appendages but was insufficient for the development of protective immune responses. 相似文献
954.
Dziedzicka-Wasylewska M Faron-Górecka A Andrecka J Polit A Kuśmider M Wasylewski Z 《Biochemistry》2006,45(29):8751-8759
Evidence for hetero-oligomerization has recently been provided for various G protein-coupled receptors. In this paper, we have studied the possibility that dopamine D(1) and D(2) receptors physically interact with each other. Human dopamine D(1) and D(2) receptors were fluorescently tagged with derivatives of green fluorescence protein and transiently coexpressed in the membrane of human embryonic kidney 293 cells. Using qualitative fluorescence spectroscopy, as well as quantitative F?rster resonance energy transfer (FRET) analysis, performed in a single cell by confocal microscopy and fluorescence lifetime microscopy, we show that dopamine D(1) and D(2) receptors can form hetero-oligomers in the plasma membrane. The degree of receptor protein-protein interaction is significantly enhanced by concomitant addition of D(1) and D(2) receptor subtype-specific agonists. Our investigations extend biochemical and electrophysiological studies and give insights into the regulation and synergistic mode of operation of dopamine receptors. 相似文献
955.
H. -M. Ku C. -W. Tan Y. -S. Su C. -Y. Chiu C. -T. Chen F. -J. Jan 《Biologia Plantarum》2012,56(2):337-343
Fluctuation in proline content is a widespread phenomenon among plants in response to heavy metal stress. To distinguish between
the participation of water deficit and copper on changes in proline metabolism, potted plants and floating leaf discs of tobacco
were subjected to CuSO4 treatments. The application of copper increased the proline content in the leaves concomitantly with decreased leaf relative
water content and increased abscisic acid (ABA) content in the potted plant. Excess copper increased the expression of two
proline synthesis genes, pyrroline-5-carboxylate synthetase (P5CS) and ornithine aminotransferase (OAT) and suppressed proline
catabolism gene, proline dehydrogenase (PDH). However, in the experiment with tobacco leaf discs floating on CuSO4 solutions, the excess copper decreased proline content and suppressed the expression of the P5CS, OAT and PDH genes. Therefore,
proline accumulation in the potted tobacco plants treated with excess Cu treatment might not be the consequence of the increased
copper content in tobacco leaves but rather by the accompanied decrease in water content and/or increased ABA content. 相似文献
956.
Yamuna Kunhi Mouvenchery Ji?í Ku?erík Doerte Diehl Gabriele E. Schaumann 《Reviews in Environmental Science and Biotechnology》2012,11(1):41-54
Interactions between cations and natural organic matter (NOM) are central for the stability of organic matter, formation of
supramolecular NOM structure, formation of organo-mineral associations, soil aggregation and binding of organic contaminants.
The effect of multivalent cations on environmental functionalities of NOM strongly depends on the relative importance between
intramolecular complexation and intermolecular cross-linking, the degree of which will be determined by the spatial arrangement
of the hydrophilic functional groups in NOM. This literature review seeks to evaluate the current state of the art regarding
the relevance of intermolecular cross-links via bridges of multivalent cations. Cross-linking has been suggested to explain
among others aggregate stability, retarded dissolved organic matter release, reduced organic matter (OM) solubility as well
as increase in degree and nonlinearity of sorption or organic chemicals to NOM. Although the cross-linking mechanism has been
suggested in numerous studies, it has not yet been verified directly. The dynamics of the intermolecular cross-links, their
persistence as well as their interplay with OM and their influence on stability and bioavailability of organic chemicals is
up to now unknown. The major challenge in this context is the development of a suitable combination of experimental and instrumental
techniques and relating the results to molecular and physicochemical models on the basis of targeted combination of spectroscopic,
molecular modelling and thermoanalytical methods. 相似文献
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The auxin/indoleacetic acid (Aux/IAA) proteins are negative regulators of the auxin response factors (ARFs) that regulate expression of auxin-responsive genes. The Aux/IAA proteins have four conserved domains. Domain II is responsible for the rapid degradation of these proteins. Degradation of the Aux/IAA proteins, mediated by a SCF(TIR1) E3 ubiquitin protein ligase complex, is critical for auxin-regulated gene expression. Using a steroid-hormone-inducible system, we had previously shown that a protein-stability-enhancing mutation in domain II of IAA1 (iaa1) impaired diverse auxin responses. Inhibition of hypocotyl elongation, leaf expansion, and stem elongation by overexpression of iaa1 suggested that cell enlargement and/or cell division might be affected. We here examined the effects of the domain II mutation on cellular anatomy using light microscopy. Our results show that overexpression of iaa1 in Arabidopsis significantly reduced cell length and cell number and affected cell shape in inflorescences and leaves in a dexamethasone (DEX)-dependent manner. These results suggest that IAA1 might be involved in cell elongation as well as in cell division in the aerial parts of Arabidopsis plants. In addition, the formation of both phloem and xylem in leaves and stems was also impaired in a DEX-dependent manner, indicating a potential involvement of IAA1 in vascular development. 相似文献
960.
Hei-Young Ku Ji-Hong Shon Kwang-Hyeon Liu Jae-Gook Shin Soo Kyung Bae 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(1-2):95-100
A rapid and sensitive LC–MS/MS method for the determination of vardenafil and its major metabolite, N-desethylvardenafil, in human plasma using sildenafil as an internal standard was developed and validated. The analytes were extracted from 0.25-mL aliquots of human plasma by liquid–liquid extraction, using 1 mL of ethyl acetate. Chromatographic separation was carried on a Luna C18 column (50 mm × 2.0 mm, 3 μm) at 40 °C, with an isocratic mobile phase consisting of 10 mM ammonium acetate (pH 5.0) and acetonitrile (10:90, v/v), a flow rate of 0.2 mL/min, and a total run time of 2 min. Detection and quantification were performed using a mass spectrometer in the selected reaction-monitoring mode with positive electrospray ionization at m/z 489.1 → 151.2 for vardenafil, m/z 460.9 → 151.2 for N-desethylvardenafil, and m/z 475.3 → 100.1 for the internal standard (IS), respectively. This assay was linear over a concentration range of 0.5–200 ng/mL with a lower limit of quantification of 0.5 ng/mL for both vardenafil and N-desethylvardenafil. The coefficient of variation for the assay precision was <13.6%, and the accuracy was >93.1%. This method was successfully applied to a pharmacokinetic study after oral administration of vardenafil 20 mg tablet in Korean healthy male volunteers. 相似文献