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71.
In the final step of tRNA splicing, the 2'-phosphotransferase catalyzes the transfer of the extra 2'-phosphate from the precursor-ligated tRNA to NAD. We have determined the crystal structure of the 2'-phosphotransferase protein from Aeropyrum pernix K1 at 2.8 Angstroms resolution. The structure of the 2'-phosphotransferase contains two globular domains (N and C-domains), which form a cleft in the center. The N-domain has the winged helix motif, a subfamily of the helix-turn-helix family, which is shared by many DNA-binding proteins. The C-domain of the 2'-phosphotransferase superimposes well on the NAD-binding fold of bacterial (diphtheria) toxins, which catalyze the transfer of ADP ribose from NAD to target proteins, indicating that the mode of NAD binding by the 2'-phosphotransferase could be similar to that of the bacterial toxins. The conserved basic residues are assembled at the periphery of the cleft and could participate in the enzyme contact with the sugar-phosphate backbones of tRNA. The modes by which the two functional domains recognize the two different substrates are clarified by the present crystal structure of the 2'-phosphotransferase. 相似文献
72.
Hashimoto K Tatsuta M Kataoka M Yasoshima K Shogase Y Shimazaki M Yura T Li Y Yamamoto N Gupta JB Urbahns K 《Bioorganic & medicinal chemistry letters》2005,15(3):799-803
A new class of benzimidazole-5-sulfonamides has been identified as nonpeptide luteinizing hormone-releasing hormone (LHRH) antagonists. Initial structure-activity relationships are presented resulting in compounds 19 and 28 with submicromolar dual functional activity on human and rat receptors. 相似文献
73.
Yamaguchi T Yamazaki T Inoue M Mashida C Kawagoe K Ogawa M Shiga S Nakagawa Y Kishimoto T Kurane I Ouchi K Ohzeki T 《FEMS immunology and medical microbiology》2005,43(1):21-27
Simkania negevensis has been associated with bronchiolitis in infants and community-acquired pneumonia in adults. Reports of exposure to this microorganism are only available from Israel, North America and Western Europe. Currently, no standard method for diagnosis of S. negevensis infection has been established nor have prevalence rates been shown in Japan. For the first time we demonstrated the ability of the microimmunofluorescence (MIF) test to detect S. negevensis-specific immunoglobulin G and exposure to S. negevensis in Japan. The positive rate in healthy volunteers was 4.3% (25/588), with rates increasing with age. Results indicate the usefulness of the MIF test as a serological method for detecting S. negevensis-specific antibodies. A standard serological test for infection with S. negevensis is needed. 相似文献
74.
A dual role of FGF10 in proliferation and coordinated migration of epithelial leading edge cells during mouse eyelid development 总被引:5,自引:0,他引:5
Tao H Shimizu M Kusumoto R Ono K Noji S Ohuchi H 《Development (Cambridge, England)》2005,132(14):3217-3230
The development of the eyelid requires coordinated cellular processes of proliferation, cell shape changes, migration and cell death. Mutant mice deficient in the fibroblast growth factor 10 (Fgf10) gene exhibit open-eyelids at birth. To elucidate the roles of FGF10 during eyelid formation, we examined the expression pattern of Fgf10 during eyelid formation and the phenotype of Fgf10-null eyelids in detail. Fgf10 is expressed by mesenchymal cells just beneath the protruding epidermal cells of the nascent eyelid. However, Fgf10-null epithelial cells running though the eyelid groove do not exhibit typical cuboid shape or sufficient proliferation. Furthermore, peridermal clumps are not maintained on the eyelid leading edge, and epithelial extension does not occur. At the cellular level, the accumulation of actin fibers is not observed in the mutant epithelial leading edge. The expression of activin/inhibin betaB (ActbetaB/Inhbb) and transforming growth factor alpha (Tgfa), previously reported to be crucial for eyelid development, is down-regulated in the mutant leading edge, while the onset of sonic hedgehog (Shh) expression is delayed on the mutant eyelid margin. Explant cultures of mouse eyelid primordia shows that the open-eyelid phenotype of the mutant is reduced by exogenous FGF10 protein, and that the expression of ActbetaB and Tgfa is ectopically induced in the thickened eyelid epithelium by the FGF10 protein. These results indicate a dual role of FGF10 in mouse eyelid development, for both proliferation and coordinated migration of eyelid epithelial cells by reorganization of the cytoskeleton, through the regulation of activin, TGFalpha and SHH signaling. 相似文献
75.
Saito S Kurakane S Seki M Takai E Kasai T Kawabata J 《Bioorganic & medicinal chemistry》2005,13(13):4191-4199
Six regio- and stereoisomers of dicaffeoyloxycyclohexanes and 2,4-di-O-caffeoyl-1,6-anhydro-beta-D-glucose were synthesized as model compounds of dicaffeoylquinic acids, and their radical scavenging activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt) radical scavenging tests. Both DPPH and ABTS radical scavenging reactions of these compounds consisted of two different steps. In the first step, catechol moieties of the caffeoyl residues were rapidly converted to o-quinone structures and no significant difference in the reactivity was observed among the tested compounds. In the second step, however, the rate of the reaction increased as the intramolecular distance of the two caffeoyl residues decreased. A novel intramolecular coupling product, which could scavenge additional radicals, was isolated from the reaction mixture of trans-1,2-dicaffeoyloxycyclohexane and DPPH radical. The result suggests that the second step of the radical scavenging reaction is arising from an intramolecular interaction between the two caffeoquinone residues to regenerate catechol structures, and that the closer their distance is, the more rapidly they react. The radical scavenging activity of natural dicaffeoylquinic acids in a biological aqueous system might also depend on the positions of caffeoyl ester groups. 相似文献
76.
Excess biglycan causes eyelid malformation by perturbing muscle development and TGF-alpha signaling 总被引:2,自引:0,他引:2
Hayashi Y Liu CY Jester JJ Hayashi M Wang IJ Funderburgh JL Saika S Roughley PJ Kao CW Kao WW 《Developmental biology》2005,277(1):222-234
Tissue morphogenesis during development is regulated by growth factors and cytokines, and is characterized by constant remodeling of extracellular matrix (ECM) in response to signaling molecules, for example, growth factors, cytokines, and so forth. Proteoglycans that bind growth factors are potential regulators of tissue morphogenesis during embryonic development. In this study, we showed that transgenic mice overexpressing biglycan under the keratocan promoter exhibited exposure keratitis and premature eye opening from noninfectious eyelid ulceration due to perturbation of eyelid muscle formation and the failure of meibomian gland formation. In addition, in vitro analysis revealed that biglycan binds to TGF-alpha, thus interrupting EGFR signaling pathways essential for mesenchymal cell migration induced by eyelid epithelium. The defects of TGF-alpha signaling by excess biglycan were further augmented by the interruption of the autocrine or paracrine loop of the EGFR signaling pathway of HB-EGF expression elicited by TGF-alpha. These results are consistent with the notion that under physiological conditions, biglycan secreted by mesenchymal cells serves as a regulatory molecule for the formation of a TGF-alpha gradient serving as a morphogen of eyelid morphogenesis. 相似文献
77.
Statins suppress oxidized low density lipoprotein-induced macrophage proliferation by inactivation of the small G protein-p38 MAPK pathway 总被引:4,自引:0,他引:4
Senokuchi T Matsumura T Sakai M Yano M Taguchi T Matsuo T Sonoda K Kukidome D Imoto K Nishikawa T Kim-Mitsuyama S Takuwa Y Araki E 《The Journal of biological chemistry》2005,280(8):6627-6633
Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) ameliorate atherosclerotic diseases. Macrophages play an important role in the development and subsequent stability of atherosclerotic plaques. We reported previously that oxidized low density lipoprotein (Ox-LDL) induced macrophage proliferation through the secretion of granulocyte/macrophage colony-stimulating factor (GM-CSF) and the consequent activation of p38 MAPK. The present study was designed to elucidate the mechanism of the inhibitory effect of statins on macrophage proliferation. Mouse peritoneal macrophages were used in our study. Cerivastatin and simvastatin each inhibited Ox-LDL-induced [(3)H]thymidine incorporation into macrophages. Statins did not inhibit Ox-LDL-induced GM-CSF production, but inhibited GM-CSF-induced p38 MAPK activation. Farnesyl transferase inhibitor and geranylgeranyl transferase inhibitor inhibited GM-CSF-induced macrophage proliferation, and farnesyl pyrophosphate and geranylgeranyl pyrophosphate prevented the effect of statins. GM-CSF-induced p38 MAPK phosphorylation was also inhibited by farnesyl transferase inhibitor or geranylgeranyl transferase inhibitor, and farnesyl pyrophosphate and geranylgeranyl pyrophosphate prevented the suppression of GM-CSF-induced p38 MAPK phosphorylation by statins. Furthermore, we found that statin significantly inhibited the membrane translocation of the small G protein family members Ras and Rho. GM-CSF-induced p38 MAPK activation and macrophage proliferation was partially inhibited by overexpression of dominant negative Ras and completely by that of RhoA. In conclusion, statins inhibited GM-CSF-induced Ras- or RhoA-p38 MAPK signal cascades, thereby suppressing Ox-LDL-induced macrophage proliferation. The significant inhibition of macrophage proliferation by statins may also explain, at least in part, their anti-atherogenic action. 相似文献
78.
Funabashi H Ishikawa M Mie M Takahashi F Yanagida Y Aizawa M Kobatake E 《Biotechnology and bioengineering》2005,90(4):509-515
We developed an electrochemical detection method for evaluating cellular physiological status based on the stringent response as a means to monitor cell viability. A reporter plasmid was constructed by inserting the beta-galactosidase gene (lacZ) under the control of the rpoS promoter, and then used to transform E. coli cells. Electrochemical responses from the products catalyzed by beta-galactosidase expressed by these E. coli cells were detected using the chronoamperometric technique in a nondestructive manner. Comparisons of response currents between the relA-positive strain and relA-negative strain revealed that increases in these currents were caused by the stringent response due to the stressful alcoholic environment, and thus as a model of stressful cultivating conditions. The current was proportional to the beta-galactosidase activity assayed by a conventional method that required the destruction of cells. The cellular physiological status, which depends on the stringent response as a viability marker, therefore, could then be evaluated online with a current using the rpoS-lacZ reporter gene in the relA-positive strain without pretreatment. 相似文献
79.
Role of the programmed death-1 pathway in regulation of alloimmune responses in vivo 总被引:7,自引:0,他引:7
Sandner SE Clarkson MR Salama AD Sanchez-Fueyo A Domenig C Habicht A Najafian N Yagita H Azuma M Turka LA Sayegh MH 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(6):3408-3415
Programmed death-1 (PD-1), an inhibitory receptor up-regulated on activated T cells, has been shown to play a critical immunoregulatory role in peripheral tolerance, but its role in alloimmune responses is poorly understood. Using a novel alloreactive TCR-transgenic model system, we examined the functions of this pathway in the regulation of alloreactive CD4+ T cell responses in vivo. PD-L1, but not PD-1 or PD-L2, blockade accelerated MHC class II-mismatched skin graft (bm12 (I-Abm12) into B6 (I-Ab)) rejection in a similar manner to CTLA-4 blockade. In an adoptive transfer model system using the recently described anti-bm12 (ABM) TCR-transgenic mice directly reactive to I-Abm12, PD-1 and PD-L1 blockade enhanced T cell proliferation early in the immune response. In contrast, at a later time point preceding accelerated allograft rejection, only PD-L1 blockade enhanced T cell proliferation. In addition, PD-L1 blockade enhanced alloreactive Th1 cell differentiation. Apoptosis of alloantigen-specific T cells was inhibited significantly by PD-L1 but not PD-1 blockade, indicating that PD-1 may not be the receptor for the apoptotic effect of the PD-L1-signaling pathway. Interestingly, the effect of PD-L1 blockade was dependent on the presence of CD4+ CD25+ regulatory T cells in vivo. These data demonstrate a critical role for the PD-1 pathway, particularly PD-1/PD-L1 interactions, in the regulation of alloimmune responses in vivo. 相似文献
80.
Exacerbation of experimental allergic asthma by augmented Th2 responses in WSX-1-deficient mice 总被引:11,自引:0,他引:11
Miyazaki Y Inoue H Matsumura M Matsumoto K Nakano T Tsuda M Hamano S Yoshimura A Yoshida H 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(4):2401-2407
WSX-1 (IL-27R) is a class I cytokine receptor with homology to gp130 and IL-12 receptors and is typically expressed on CD4+ T lymphocytes. Although previous reports have clarified that IL-27/WSX-1 signaling plays critical roles in both Th1 differentiation and attenuation of cell activation and proinflammatory cytokine production during some bacterial or protozoan infections, little is known about the importance of WSX-1 in cytokine-mediated diseases of allergic origin. To this aim, we took advantage of WSX-1-deficient (WSX-1(-/-)) mice and induced experimental asthma, in which Th2 cytokines are central modulators of the pathology. OVA-challenged WSX-1(-/-) mice showed marked enhancement of airway responsiveness with goblet cell hyperplasia, pulmonary eosinophil infiltration, and increased serum IgE levels compared with wild-type mice. Production of Th2 cytokines, which are largely responsible for the pathogenesis of asthma, was augmented in the lung or in the culture supernatants of peribronchial lymph node CD4+ T cells from WSX-1(-/-) mice compared with those from wild-type mice. Surprisingly, IFN-gamma production was also enhanced in WSX-1(-/-) mice, albeit at a low concentration. The cytokine overproduction, thus, seems independent from the Th1-promoting property of WSX-1. These results demonstrated that IL-27/WSX-1 also plays an important role in the down-regulation of airway hyper-reactivity and lung inflammation during the development of allergic asthma through its suppressive effect on cytokine production. 相似文献