722 research outputs found
Structural basis for RanGTP independent entry of spliceosomal U snRNPs into the nucleus
No full textThe nuclear import of assembled spliceosomal subunits, the uridine rich small nuclear ribonucleoprotein particles U snRNPs , is mediated by a nuclear import receptor adaptor couple of importin amp; 946; Imp amp; 946; and snurportin1 SPN1 . In contrast to any other characterized active nuclear import, the Imp amp; 946; SPN1 U snRNP complex does not require RanGTP for the terminal release from the nuclear basket of the nuclear pore complex NPC . The crystal structure of Imp amp; 946; 127 876 in complex with the Imp amp; 946; binding IBB domain of SPN1 1 65 at 2.8 resolution reveals that Imp amp; 946; adopts an open conformation, which is unique for a functional Imp amp; 946; cargo complex, and rather surprisingly, it resembles the conformation of the Imp amp; 946; RanGTP complex. As binding of RanGTP to Imp amp; 946; usually triggers the release of import complexes from the NPC, we propose that by already mimicking a conformation similar to Imp amp; 946; RanGTP the independent dissociation of Imp amp; 946; SPN1 from the nuclear basket is energetically aide
Structure analysis of the conserved methyltransferase domain of human trimethylguanosine synthase TGS1
No full textMethyltransferases play an important role in the post-transcriptional maturation of most ribonucleic acids. The modification of spliceosomal UsnRNAs includes N2-dimethylation of the m(7)G cap catalyzed by trimethylguanosine synthase 1 (TGS1). This 5'-cap hypermethylation occurs during the biogenesis of UsnRNPs as it initiates the m(3)G cap-dependent nuclear import of UsnRNPs. The conserved methyltransferase domain of human TGS1 has been purified, crystallized and the crystal structure of this domain with bound substrate m(7)GpppA was solved by means of multiple-wavelength anomalous dispersion. Crystal structure analysis revealed that m(7)GpppA binds via its adenosine moiety to the structurally conserved adenosylmethionine-binding pocket, while the m(7) guanosine remains unbound. This unexpected binding only occurs in the absence of AdoMet and suggests an incomplete binding pocket for the m(7)G cap which is caused by the N-terminal truncation of the protein. These structural data are consistent with the finding that the crystallized fragment of human TGS1 is catalytically inactive, while a fragment that is 17 amino acids longer exhibits activity
Thermodynamic analysis of H1 nuclear import - Receptor tuning of importin beta/importin7
No full textThe nuclear import of H1 linker histones is mediated by a heterodimer of transport receptors, known as importin beta and importin7. Interestingly, both importins separately interact with H1, but only as a dimer they facilitate the translocation through the nuclear pore. We identified the H1 binding site of importin7, comprising two extended acidic loops near the C terminus of importin7. The analysis of the H1 import complex assembly by means of isothermal titration calorimetry revealed that the formation of a receptor heterodimer in vitro is an enthalpy-driven process, whereas subsequent binding of H1 to the heterodimer is entropy-driven. Furthermore, we show that the importin beta binding domain of importin7 plays a key role in the activation of importin7 by importin beta. This process is allosterically regulated by importin beta and accounts for a specific tuning of the activity of the importin beta center dot importin7 heterodimer. The results presented here provide new insights into cellular strategies to even energy balances in nuclear import and point toward a general regulation of importin beta-related nuclear import processes
Institutionalizing ASEAN: celebrating Europe through network governance
No full textThis article provides a new piece for two of the puzzles of institutionalized cooperation in Association of Southeast Asian Nations (ASEAN). First, with regard to the organization's four decades of existence, there has always been a marked gap between ASEAN's rhetorical goals of cooperation and its actual achievements. What explains these systematic failures of implementation? Second, from the outset, ASEAN was criticized for its light institutionalization, which failed to deliver the substantial cooperation goals. Despite selected institutional reforms, ASEAN's autonomy has not increased remarkably and it has not made any major institutional innovations. Why does ASEAN design institutions it does not use? Why does this transformation gap occur? The author suggests a sociological institutional explanation and argues that major impulses for cooperation have come from outside Southeast Asia, most importantly from Europe. By mimicking the European integration process, ASEAN member states have effectively created an isomorphic organization. The Association's institutional development reflects a concern for international legitimacy and less an objective functional demand arising from the specific interactions of member states. This copying process has led to network governance within the organization
The Vietnamese Theatrical Tradition in the Plot of Monsun, by Anja Hillin
No full textFrom the dramatic text Monsun by the German author Anja Hilling, this article analyzes the construction of a plot using elements of the Asian theater, in this specific case the Vietnamese tradition, identifying its presence inthe structure beyond the constant references to the context of that country, starting with the title of the play itself and the trip of one of the characters to Vietnam.A partir do texto dramático Monsun, da autora alemã Anja Hilling, este artigo analisa a construção de uma trama que se utiliza de elementos do teatro asiático, neste caso específico a tradição vietnamita, identi cando a sua presença na estrutura, além das men- ções constantes ao contexto daquele país, começando pelo próprio título da peça e pela viagem de uma das personagens ao Vietnam. 
Discussing Anja Štefan`s fairytales in the first year of primary school
No full textFairytales are an indispensable part in children's lives. They stimulate the development of imagination, fantasy; they help to enrich children’s vocabulary and with expressing feelings. There are different types of fairytales and it is very important that children get to know the variety of them. I firstly presented a youth author Anja Štefan and her literary works in my diploma paper. Later on I continued with the presentation of youth literature and I defined the theory of a fairytale, wrote about the origin, its meaning and classification of fairytales which I have also described in greater detail. I stated and described authorial prose work of Anja Štefan: picture book Lešniki, lešniki and classic fairytales Kotiček na koncu sveta, Melje, melje mlinček and Štiri črne mravljice, which can be defined as animal fairytales. I was interested in the receptive development of children in the period of intuitive intelligence, which I thoroughly described. In the empirical part of my diploma I wrote lesson plans for discussing and teaching three Anja Štefan’s animal fairytales in the first grade of primary school. 25 children took part in the research. I found out that pupils distinguish between real and unreal life (imaginative life), they are capable of identifying themselves with a literary person and they perceive animals as literary persons and they identify themselves with them
Correction to: Predicting the effectiveness of protected areas of Natura 2000 under climate change
No full textIn the original publication of this article (Nila & Hossain, 2019), co-authors ‘Carl Beierkuhnlein, Anja Jaeschke and Samuel Hoffmann’ need to be added to the author list
Structural basis for m(3)G-cap-mediated nuclear import of spliceosomal UsnRNPs by snurportin1
No full textIn higher eukaryotes the biogenesis of spliceosomal UsnRNPs involves a nucleocytoplasmic shuttling cycle. After the m(7) G-cap-dependent export of the snRNAs U1, U2, U4 and U5 to the cytoplasm, each of these snRNAs associates with seven Sm proteins. Subsequently, the m(7)G-cap is hypermethylated to the 2,2,7-trimethylguanosine (m(3)G)-cap. The import adaptor snurportin1 recognises the m(3)G-cap and facilitates the nuclear import of the UsnRNPs by binding to importin-beta. Here we report the crystal structure of the m(3)G-cap-binding domain of snurportin1 with bound m(3)GpppG at 2.4 angstrom resolution, revealing a structural similarity to the mRNA-guanylytransferase. Snurportin1 binds both the hypermethylated cap and the first nucleotide of the RNA in a stacked conformation. This binding mode differs significantly from that of the m(7)G-cap-binding proteins Cap-binding protein 20 (CBP20), eukaryotic initiation factor 4E (eIF4E) and viral protein 39 (VP39). The specificity of the m(3)G-cap recognition by snurportin1 was evaluated by fluorescence spectroscopy, demonstrating the importance of a highly solvent exposed tryptophan for the discrimination of m(7)G-capped RNAs. The critical role of this tryptophan and as well of a tryptophan continuing the RNA base stack was confirmed by nuclear import assays and cap-binding activity tests using several snurportin1 mutants
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