Consequences of Eukaryotic Enhancer Architecture for Gene Expression Dynamics, Development, and Fitness

The regulatory logic of time- and tissue-specific gene expression has mostly been dissected in the context of the smallest DNA fragments that, when isolated, recapitulate native expression in reporter assays. It is not known if the genomic sequences surrounding such fragments, often evolutionarily conserved, have any biological function or not. Using an enhancer of the even-skipped gene of Drosophila as a model, we investigate the functional significance of the genomic sequences surrounding empirically identified enhancers. A 480 bp long “minimal stripe element” is able to drive even-skipped expression in the second of seven stripes but is embedded in a larger region of 800 bp containing evolutionarily conserved binding sites for required transcription factors. To assess the overall fitness contribution made by these binding sites in the native genomic context, we employed a gene-replacement strategy in which whole-locus transgenes, capable of rescuing even-skipped- lethality to adulthood, were substituted for the native gene. The molecular phenotypes were characterized by tagging Even-skipped with a fluorescent protein and monitoring gene expression dynamics in living embryos. We used recombineering to excise the sequences surrounding the minimal enhancer and site-specific transgenesis to create co-isogenic strains differing only in their stripe 2 sequences. Remarkably, the flanking sequences were dispensable for viability, proving the sufficiency of the minimal element for biological function under normal conditions. These sequences are required for robustness to genetic and environmental perturbation instead. The mutant enhancers had measurable sex- and dose-dependent effects on viability. At the molecular level, the mutants showed a destabilization of stripe placement and improper activation of downstream genes. Finally, we demonstrate through live measurements that the peripheral sequences are required for temperature compensation. These results imply that seemingly redundant regulatory sequences beyond the minimal enhancer are necessary for robust gene expression and that “robustness” itself must be an evolved characteristic of the wild-type enhancer

Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA

Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 LT = Q(2) LT = 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) LT = x LT = 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined

Measurement of colour flow with the jet pull angle in View the MathML sourcett¯ events using the ATLAS detector at View the MathML sources=8 TeV

The distribution and orientation of energy inside jets is predicted to be an experimental handle on colour connections between the hard-scatter quarks and gluons initiating the jets. This Letter presents a measurement of the distribution of one such variable, the jet pull angle. The pull angle is measured for jets produced in View the MathML sourcett¯ events with one W boson decaying leptonically and the other decaying to jets using 20.3 fb−1 of data recorded with the ATLAS detector at a centre-of-mass energy of View the MathML sources=8 TeV at the LHC. The jet pull angle distribution is corrected for detector resolution and acceptance effects and is compared to various models

In vitro detection of complement-fixing alloantibodies in kidney transplantation

Die Nierentransplantation stellt den Goldstandard der Therapie bei Patienten mit chronischer Niereninsuffizienz dar. Trotz beachtlicher wissenschaftlicher Erfolge auf dem Gebiet der Diagnostik und Therapie akuter Transplantatabstoßung, sind die Langzeitergebnisse noch nicht zufriedenstellend. Zu viele Organe werden durch chronische Transplantatschädigung verloren. Dabei spielen immunologische Prozesse, vor allem Antikörper gegen das körperfremde Transplantat (HLA Antikörper bzw. Alloantikörper), eine bedeutende Rolle. Die Fähigkeit dieser Alloantikörper das Komplementsystem zu aktivieren, könnte dabei entscheidend zu sein. Unsere Arbeitsgruppe hat einen auf Durchflusszytometrie basierenden Test entwickelt, der zwischen Komplement und nicht Komplement aktivierenden Alloantikörpern unterscheiden kann ([C4d]FlowPRA). Dabei wird nicht nur wie bisher der Antikörper selbst detektiert ([IgG]FlowPRA), sondern auch das, bei der Komplementaktivierung anfallende, Komplementspaltprodukt C4d. In einer Vorarbeit konnten wir zeigen, dass Patienten mit Komplement aktivierenden Alloantikörpern vor Transplantation das Transplantat früher verlieren, als Patienten bei denen nur Antikörper ohne Komplementaktivierungsfähigkeit nachweisbar waren. Die vorliegende Arbeit beschäftigt sich nun mit der Entstehung, Detektion und klinischen Wertigkeit Komplement aktivierender Alloantikörper. Dabei wird die Wertigkeit von Komplement aktivierenden Alloantikörpern zur Diagnose einer, in der Biopsie Komplementspaltprodukt C4d ablagernden, Transplantatdysfunktion untersucht. Es wird gezeigt, dass vor allem durch die hohe Sensitivität der Nachweis Komplement aktivierender Alloantikörper in der Diagnostik einer C4d positiven Transplantatdysfunktion in Zukunft als wertvoller Marker dienen kann. Die Daten zeigen, dass das Vorhanden sein von Alloantikörpern bei klinisch stabilen Patienten jedoch keine Aussage über die Transplantatlangzeitfunktion zulässt.Kidney transplantation represents the gold standard for treatment of end stage renal disease. Despite great advantages in treatment and diagnosis of acute graft rejection, graft loss due to chronic allograft nephropathy (CAN) remains an unsolved problem. The presence of preformed alloantibodies against Human Leukocyte Antigens (HLA) of the donor (donor specific alloantibodies =DSA) poses a particular risk for kidney allograft rejection. The capability of these alloantibodies to activate the complement system may be pivotal for graft damage. Our group has recently developed a FlowPRA-based method ([C4d]FlowPRA) permitting discrimination between complement and non complement fixing alloantibodies. In addition to conventional alloantibody detection [CIgG]FlowPRA) alloantibody triggered deposition of human complement split product C4d is measured. Applying this technique for pretransplant screening, kidney allograft recipients with complement-fixing pre-sensitization were found to experience significantly worse graft survival than those with non complement-fixing or no sensitization. The present work describes origin, detection methods and clinical relevance of complement-fixing anti HLA alloantibodies. Results: In graft dysfunction the detection of complement-fixing alloantibodies provides a specific tool for diagnostic of C4dpositive Antibody mediated rejection. In contrast in the absence of early graft dysfunction the presence of alloantibodies is not always a marker for later graft dysfunction and thus should be interpreted with caution.Gregor Bartelhttp://www.ncbi.nlm.nih.gov/sites/entrez Suchfeld: Bartel GZsfassung in dt. SpracheWien, Med. Univ., Diss., 2009OeBB(VLID)171408

Virtue ethics and social psychology

Virtue ethics has emerged as an alternative to deontological and utilitarian theory in recent moral philosophy. The basic notion of virtue ethics is to reassert the importance of virtuous character in ethical judgement in contrast to the emphasis on principles and consequences. Since questions of virtue have been largely neglected in modern moral theory, there has been a return to Aristotle’s account of virtue as character. This in turn has been questioned as the basis of virtue ethics and there has been a search for alternative accounts of moral agency. One aspect of this critical reflection on virtue ethics is an engagement with social psychology as a source of criticism of the Aristotelian conception of character and as a more plausible alternative foundation for a theory of moral character with contemporary relevance. This paper aims to introduce this area of moral theory to a psychological audience and reflect on the interpretation of social psychological theory and evidence in criticisms of virtuous character, focusing on the use of Milgram’s (1974) experiments on obedience to authority as an argument for situationism. A number of questions emerge concerning the interpretation and use of social psychological theory and evidence in debates within moral philosophy