Search results for "SITES"
showing 10 items of 2851 documents
Transcriptional activation of the small GTPase gene rhoB by genotoxic stress is regulated via a CCAAT element
2001
The gene encoding the Ras-related GTPase RhoB-specific is immediate-early inducible by genotoxic treatments. Regulation of transcriptional activation of rhoB is still unclear. Here we show that cells lacking either p53 or c-Fos are not different from wild-type cells with respect to the level of rhoB induction upon UV irradiation, indicating that these transcription factors are not crucial for stimulation of rhoB mRNA expression. Extracts from UV-irradiated and non-irradiated cells revealed similar DNA-binding activities to a 0.17 kb rhoB promoter fragment harboring the functional element(s) necessary for stimulation of rhoB by UV light. By means of immunoprecipitation we found that an ATF-2…
Role of hepatocyte nuclear factor 3γ in the expression of human CYP2C genes
2004
Hepatocyte nuclear factor 3 gamma (HNF-3 gamma) is an important transcription factor for the maintenance of specific liver functions. However, its relevance in the expression of human cytochrome P450 (CYP) genes has not yet been explored. Several HNF3 putative binding sites can be identified in human CYP2C 5'-flanking regions. Gene reporter experiments with proximal promoters revealed that HNF-3 gamma transactivated CYP2C8, CYP2C9, and CYP2C19 (25-, 4-, and 4-fold, respectively), but it did not transactivate CYP2C18. However, overexpression of HNF-3 gamma in hepatoma cells by means of a recombinant adenovirus induced CYP2C9, CYP2C18, and CYP2C19 mRNA (4.5-, 20-, and 50-fold, respectively) b…
Differential Regulation of CCL22 Gene Expression in Murine Dendritic Cells and B Cells
2005
Abstract The activated T cell-attracting CC chemokine CCL22 is expressed by stimulated B cells and mature dendritic cells (DC). We have cloned and sequenced the complete mouse gene, including 4 kb of the 5′-flanking promoter region, and detected two distinct sites for initiation of transcription by 5′-RACE. Reporter gene assays indicate that the promoter reflects the specificity of the endogenous gene. Within the proximal promoter region, we identified potential binding sites for NF-κB, Ikaros, and a putative GC box. All three regions bind proteins. The NF-κB site was shown to specifically bind NF-κB subunits p50 and p65 from nuclear extracts of LPS-stimulated B cells, B cell line A20/2J, T…
Synthetic retinoids dissociate coactivator binding from corepressor release.
2002
The ligand-activated retinoid receptors RXR and RAR control development, homeostasis and disease by regulating transcription of retinoic acid (RA) responsive target genes or crosstalk with other signalling pathways. According to the current model ligand-binding triggers an exchange between corepressor- and coactivator-complexes that inhibit or potentiate transcription by deacetylating and acetylating nucleosomal histones, respectively. Additional cofactors may modify the transcriptional regulatory process by linking liganded retinoid receptors to structural components of chromatin or protein degradation. The desire to specifically influence defined events in RA-signalling, while others are …
Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets
2001
In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet contai…
Synthesis and luminescent properties of Mn-doped alpha-tricalcium phosphate
2021
This project has received funding from European Social Fund (project No 09.3.3-LMT-K-712-19-0069) under grant agreement with the Research Council of Lithuania (LMTLT). Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART². The World Federation of Scientists is highly acknowledged for the National Scholarship to AZ. © 2021. This work is licensed under a CC BY-NC-ND 4.0 license.
Catalytic asymmetric conjugate addition of terminal alkynes to β-trifluoromethyl α,β-enones.
2014
The first enantioselective conjugate alkynylation of β-trifluoromethyl α,β-enones using terminal alkynes and a taniaphos–Cu(I) complex as catalyst is described. Ketones bearing a trifluoromethylated propargylic chiral centre in the β-position were obtained with good yields and high enantiomeric excesses (up to 99%).
Highly enantioselective copper(I)-catalyzed conjugate addition of 1,3-diynes to a,b-unsaturated trifluoromethyl ketones
2015
[EN] The conjugate diynylation of a,b-unsaturated trifluoromethyl ketones is carried out in the presence of a low catalytic load (2.5 mol%) of a copper(I)–MeOBIPHEP complex, triethylamine and a terminal 1,3-diyne. Pre-metalation of the terminal 1,3-diyne with stoichiometric or higher amounts of dialkylzinc reagent is not required. The corresponding internal diynes bearing a propargylic stereogenic center are obtained with good yields and excellent enantioselectivities.
Distinct photodynamics of κ-N and κ-C pseudoisomeric iron(ii) complexes
2021
Two closely related FeII complexes with 2,6-bis(1-ethyl-1H-1,2,3-triazol-4yl)pyridine and 2,6-bis(1,2,3-triazol-5-ylidene)pyridine ligands are presented to gain new insights into the photophysics of bis(tridentate) iron(II) complexes. The [Fe(N^N^N)2]2+ pseudoisomer sensitizes singlet oxygen through a MC state with nanosecond lifetime after MLCT excitation, while the bis(tridentate) [Fe(C^N^C)2]2+ pseudoisomer possesses a similar 3MLCT lifetime as the tris(bidentate) [Fe(C^C)2(N^N)]2+ complexes with four mesoionic carbenes. Financial support from the Deutsche Forschungsge-meinschaft [DFG, Priority Program SPP 2102] "Light-controlled reactivity of metal complexes" (BA 4467/7-1, LO 714/11-1, …
Hydrogen activation with perfluorinated organoboranes: 1,2,3-tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene
2013
The perfluorinated boraindene was synthesized and fully characterized. Both computational and crystallographic data show that is antiaromatic. Compound was shown to react reversibly with H2 and to catalyse the hydrogenation of cyclohexene. The mechanism of catalysis was probed experimentally and computationally.