951 resultados para TRANSCRIPTION TERMINATION


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A better understanding of the mechanisms by which most focal epileptic seizures stop spontaneously within a few minutes would be of highest importance, because they could potentially help to improve existing and develop novel therapeutic measures for seizure control. Studies devoted to unraveling mechanisms of seizure termination often take one of the two following approaches. The first approach focuses on metabolic mechanisms such as ionic concentrations, acidity, or neuromodulator release, studying how they are dependent on, and in turn affect changes of neuronal activity. The second approach uses quantitative tools to derive functional networks from electrophysiological recordings and analyzes these networks with mathematical methods, without focusing on actual details of cell biology. In this chapter, we summarize key results obtained by both of these approaches and attempt to show that they are complementary and equally necessary in our aim to gain a better understanding of seizure termination.

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The poster demonstrates the preparatory steps of a digital multi-text edition that are abstracted from the experiences made in the Parzival Project, based at the University of Bern, the Berlin-Brandenburg Academy of Sciences and the University of Erlangen. This edition of Wolfram von Eschenbach’s German Grail novel, written shortly after 1200 and transmitted during several centuries in ca. hundred witnesses, has now been completed by more than a half of the textual corpus. As the text is transmitted in medieval manuscripts the witnesses have to be transcribed according to specific encoding rules. The transcriptions then are collated following certain ideas and concepts of how the transmission process could have developed. The transcriptions and collations finally have to be transferred to a digital edition that allows the users to explore the characteristics of single witnesses as well as the history of a text, which is delivered in variants and in different versions. A dynamically organized database offering various components and adapted to the needs of diverse user-profiles is nowadays the right tool for this purpose.

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Nonsense-mediated mRNA decay (NMD) is best known for its role in quality control of mRNAs, where it recognizes premature translation termination codons (PTCs) and rapidly degrades the corresponding mRNA. The basic mechanism of NMD appears to be conserved among eukaryotes: aberrant translation termination triggers NMD. According to the current working model, correct termination requires the interaction of the ribosome with the poly(A)-binding protein (PABPC1) mediated through the eukaryotic release factors 1 (eRF1) and 3 (eRF3). The model predicts that in the absence of this interaction, the NMD core factor UPF1 binds to eRF3 instead and initiates the events ultimately leading to mRNA degradation. However, the exact mechanism of how the decision between proper and aberrant (i.e. NMD-inducing) translation termination occurs is not yet well understood. We address this question using a tethering approach in which proteins of interest are bound to a reporter transcript into the vicinity of a PTC. Subsequently, the ability of the tethered proteins to inhibit NMD and thus stabilize the reporter transcript is assessed. Our results revealed that the C-terminal domain interacting with eRF3 seems not to be necessary for tethered PABPC1 to suppress NMD. In contrast, the N-terminal part of PABPC1, consisting of 4 RNA recognition motifs (RRMs) and interacting with eukaryotic initiation factor 4G (eIF4G), retains the ability to inhibit NMD. We find that eIF4G is able to inhibit NMD in a similar manner as PABPC1 when tethered to the reporter mRNA. This stabilization by eIF4G depends on two key interactions. One of these interactions is to PABPC1, the other is to eukaryotic initiation factor 3 (eIF3). These results confirm the importance of PABPC1 in inhibiting NMD but additionally reveal a role of translation initiation factors in the distinction between bona fide termination codons and PTCs.

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The poster demonstrates the preparatory steps of a digital multi-text edition that are abstracted from the experiences made in the Parzival Project, based at the University of Bern, the Berlin-Brandenburg Academy of Sciences and the University of Erlangen. This edition of Wolfram von Eschenbach’s German Grail novel, written shortly after 1200 and transmitted during several centuries in ca. hundred witnesses, has now been completed by more than a half of the textual corpus.

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Helicobacter pylori infects the human gastric mucosa causing a chronic infection that is the primary risk factor for gastric cancer development. Recent studies demonstrate that H. pylori promotes tolerogenic dendritic cell (DC) development indicating that this bacterium evades the host immune response. However, the signaling pathways involved in modulating DC activation during infection remain unclear. Here, we report that H. pylori infection activated the signal transducer and activator of transcription 3 (STAT3) pathway in murine bone marrow-derived DCs (BMDCs) and splenic DCs isolated ex vivo. Isogenic cagA-, cagE-, vacA- and urease-mutants exhibited levels of phosphoSTAT3 that were comparable to in the wild-type (WT) parent strain. H. pylori-infected BMDCs produced increased immunosuppressive IL-10, which activated STAT3 in an autocrine/paracrine fashion. Neutralization of IL-10 prevented H. pylori-mediated STAT3 activation in both BMDCs and splenic DCs. In addition, anti-IL-10 treatment of infected H. pylori-BMDCs was associated with increased CD86 and MHC II expression and enhanced proinflammatory IL-1β cytokine secretion. Finally, increased CD86 and MHC II expression was detected in H. pylori-infected STAT3 knockout DCs when compared to WT controls. Together, these results demonstrate that H. pylori infection induces IL-10 secretion in DCs, which activates STAT3, thereby modulating DC maturation and reducing IL-1β secretion. These findings identify a host molecular mechanism by which H. pylori can manipulate the innate immune response to potentially favor chronic infection and promote carcinogenesis. © 2014 S. Karger AG, Basel.

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BACKGROUND -This study aimed to determine five-year efficacy of catheter ablation for persistent atrial fibrillation (PsAF) using AF termination as a procedural endpoint. METHODS AND RESULTS -150 patients (57±10 years) underwent PsAF ablation using a stepwise ablation approach (pulmonary vein isolation, electrogram-guided and linear ablation) with the desired procedural endpoint being AF termination. Repeat ablation was performed for recurrent AF or atrial tachycardia (AT). AF was terminated by ablation in 120 patients (80%). Arrhythmia-free survival rates after a single procedure were 35.3±3.9%, 28.0±3.7%, and 16.8±3.2% at 1, 2, and 5 years, respectively. Arrhythmia-free survival rates after the last procedure (mean 2.1±1.0 procedures) were 89.7±2.5%, 79.8±3.4%, and 62.9±4.5%, at 1, 2, and 5 years, respectively. During a median follow-up of 58 (IQR 43-73) months following the last ablation procedure, 97 of 150 (64.7%) patients remained in sinus rhythm without antiarrhythmic drugs (AADs). Another 14 (9.3%) patients maintained sinus rhythm after re-initiation of AADs, and an additional 15 (10.0%) patients regressed to paroxysmal recurrences only. Failure to terminate AF during the index procedure (HR 3.831; 95%CI: 2.070-7.143; p<0.001), left atrial diameter ≥50mm (HR 2.083; 95%CI: 1.078-4.016; p=0.03), continuous AF duration ≥18 months (HR 1.984; 95%CI: 1.024-3.846; p<0.04) and structural heart disease (HR 1.874; 95% CI: 1.037-3.388; p=0.04) predicted arrhythmia recurrence. CONCLUSIONS -In patients with PsAF, an ablation strategy aiming at AF termination is associated with freedom from arrhythmia recurrence in the majority of patients over a 5-year follow up period.Procedural AF non-termination and specific baseline factors predict long-term outcome after ablation.

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Chordoid glioma of the third ventricle is a rare neuroepithelial tumor characterized by a unique histomorphology and exclusive association with the suprasellar/third ventricular compartment. Variously interpreted as either astrocytic- or ependymal-like, and speculatively ascribed to the lamina terminalis/subcommissural organ, its histogenesis remains, nevertheless, unsettled. Here, we report on a suprasellar chordoid glioma occurring in a 52-year-old man. Although displaying otherwise typical morphological features, the tumor was notable for expression of thyroid transcription factor 1, a marker of tumors of pituicytic origin in the context of the sellar region. We furthermore found overlapping immunoprofiles of this example of chordoid glioma and pituicytic tumors (pituicytoma and spindle cell oncocytoma), respectively. Specifically, phosphorylated ribosomal protein S6, a marker of mTOR pathway activation, was expressed in both groups. Based on these findings, we suggest that chordoid glioma and pituicytic tumors may form part of a spectrum of lineage-related neoplasms of the basal forebrain.

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Thyroid transcription factor 1 (TTF-1) is encoded by the NKX2-1 homeobox gene. Besides specifying thyroid and pulmonary organogenesis, it is also temporarily expressed during embryonic development of the ventral forebrain. We recently observed widespread immunoreactivity for TTF-1 in a case of subependymal giant cell astrocytoma (SEGA, WHO grade I) – a defining lesion of the tuberous sclerosis complex (TSC). This prompted us to investigate additional SEGAs in this regard. We found tumor cells in all 7 specimens analyzed to be TTF-1 positive. In contrast, we did not find TTF-1 immunoreactivity in a cortical tuber or two renal angiomyolipomas resected from TSC patients. We propose our finding of consistent TTF-1 expression in SEGAs to indicate lineage-committed derivation of these tumors from a regionally specified cell of origin. The medial ganglionic eminence, ventral septal region, and preoptic area of the developing brain may represent candidates for the origin of SEGAs. Such lineagerestricted histogenesis may also explain the stereotypic distribution of SEGAs along the caudate nucleus in the lateral ventricles.

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Replication-dependent histone genes are up-regulated during the G1/S phase transition to meet the requirement for histones to package the newly synthesized DNA. In mammalian cells, this increment is achieved by enhanced transcription and 3' end processing. The non-polyadenylated histone mRNA 3' ends are generated by a unique mechanism involving the U7 small ribonucleoprotein (U7 snRNP). By using affinity purification methods to enrich U7 snRNA, we identified FUS/TLS as a novel U7 snRNP interacting protein. Both U7 snRNA and histone transcripts can be precipitated by FUS antibodies predominantly in the S phase of the cell cycle. Moreover, FUS depletion leads to decreased levels of correctly processed histone mRNAs and increased levels of extended transcripts. Interestingly, FUS antibodies also co-immunoprecipitate histone transcriptional activator NPAT and transcriptional repressor hnRNP UL1 in different phases of the cell cycle. We further show that FUS binds to histone genes in S phase, promotes the recruitment of RNA polymerase II and is important for the activity of histone gene promoters. Thus, FUS may serve as a linking factor that positively regulates histone gene transcription and 3' end processing by interacting with the U7 snRNP and other factors involved in replication-dependent histone gene expression.

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Retirement from elite sports requires athletes to cope with adjustments on an occupational, financial, physical, social or emotional level. Research on critical life events (e.g., Filipp & Aymanns, 2010) suggests that benefit finding, defined as “the process of deriving positive growth from adversity” (Cassidy et al., 2014), may have a positive impact on this transition. The present study examined the effects of benefit finding on the quality of adjustment to career termination in the short, middle and long term. Former Swiss elite athletes (N = 290) completed a written survey collecting information on a) their emotional reaction to career termination, b) the amount of adjustment in various respects, c) situational characteristics of their career termination, d) the duration and quality of the transition, and e) their subjective well-being. Using Latent Variable Modelling, finding benefit in career termination was found to have both a direct and an indirect effect on long-term well-being (γ=.18). It predicts favorable emotional reactions to career termination (γ = .53) and less adjustment (γ = -.38) which in turn shortens the transition duration (β = -.15 and β = .55, respectively) and quality (β = -.15), and finally augments well-being (β = .41). The data suggest that a focus on benefit finding in both crisis-prevention and crisis-coping interventions may prove useful to prevent crisis transitions.

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Ethylene responsive factors (ERFs) are a large family of plant-specific transcription factors that are involved in the regulation of plant development and stress responses. However, little to nothing is known about their role in herbivore-induced defense. We discovered a nucleus-localized ERF gene in rice (Oryza sativa), OsERF3, that was rapidly up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis. Antisense and over-expression of OsERF3 revealed that it positively affects transcript levels of two mitogen-activated protein kinases (MAPKs) and two WRKY genes as well as concentrations of jasmonate (JA), salicylate (SA) and the activity of trypsin protease inhibitors (TrypPIs). OsERF3 was also found to mediate the resistance of rice to SSB. On the other hand, OsERF3 was slightly suppressed by the rice brown planthopper (BPH) Nilaparvata lugens (Stål) and increased susceptibility to this piercing sucking insect, possibly by suppressing H2O2 biosynthesis. We propose that OsERF3 affects early components of herbivore-induced defense responses by suppressing MAPK repressors and modulating JA, SA, ethylene and H2O2 pathways as well as plant resistance. Our results also illustrate that OsERF3 acts as a central switch that gears the plant’s metabolism towards an appropriate response to chewing or piercing/sucking insects.

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The mechanisms by which herbivore-attacked plants activate their defenses are well studied. By contrast, little is known about the regulatory mechanisms that allow them to control their defensive investment and avoid a defensive overshoot. We characterized a rice (Oryza sativa) WRKY gene, OsWRKY53, whose expression is rapidly induced upon wounding and induced in a delayed fashion upon attack by the striped stem borer (SSB) Chilo suppressalis. The transcript levels of OsWRKY53 are independent of endogenous jasmonic acid but positively regulated by the mitogen-activated protein kinases OsMPK3/OsMPK6. OsWRKY53 physically interacts with OsMPK3/OsMPK6 and suppresses their activity in vitro. By consequence, it modulates the expression of defensive, MPK-regulated WRKYs and thereby reduces jasmonic acid, jasmonoyl-isoleucine, and ethylene induction. This phytohormonal reconfiguration is associated with a reduction in trypsin protease inhibitor activity and improved SSB performance. OsWRKY53 is also shown to be a negative regulator of plant growth. Taken together, these results show that OsWRKY53 functions as a negative feedback modulator of MPK3/MPK6 and thereby acts as an early suppressor of induced defenses. OsWRKY53 therefore enables rice plants to control the magnitude of their defensive investment during early signaling.

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A Review of Premature Termination in Psychotherapy: Strategies for Engaging Clients and Improving Outcomes by Joshua K. Swift and Roger P. Greenberg Washington, DC: American Psychological Association. 2015. 212 pp, ISBN 978-1-4338-1801- 1. $69.95 http://dx.doi.org/10.1037/a0038612 Premature Termination in Psychotherapy: Strategies for Engaging Clients and Improving Outcomes is one of the very best examples of the new generation of psychotherapy development. Based on rigorous research findings and a deep look into the preexisting literature, this book presents practical guidelines to understand premature termination and provides evidence-based strategies for how to engage patients in treatment. It will especially be a highlight for practitioners who are interested in a broad insight of the overall empirical literature. For graduate students in clinical and counseling psychology, this book might be an excellent prototype for how to bring rigorous quantitative research and convenient practice examples together.