1,594 research outputs found
Identification of proteins and miRNAs that specifically bind an mRNA in vivo
Understanding regulation of an mRNA requires knowledge of its regulators. However, methods for reliable de-novo identification of proteins binding to a particular RNA are scarce and were thus far only successfully applied to abundant noncoding RNAs in cell culture. Here, we present vIPR, an RNA-protein crosslink, RNA pulldown, and shotgun proteomics approach to identify proteins bound to selected mRNAs in C. elegans. Applying vIPR to the germline-specific transcript gld-1 led to enrichment of known and novel interactors. By comparing enrichment upon gld-1 and lin-41 pulldown, we demonstrate that vIPR recovers both common and specific RNA-binding proteins, and we validate DAZ-1 as a specific gld-1 regulator. Finally, combining vIPR with small RNA sequencing, we recover known and biologically important transcript-specific miRNA interactions, and we identify miR-84 as a specific interactor of the gld-1 transcript. We envision that vIPR will provide a platform for investigating RNA in vivo regulation in diverse biological systems
Post-transcriptional regulation by 3' UTRs can be masked by regulatory elements in 5' UTRs
In mRNA sequences, 3' UTRs are thought to contain most elements that specifically regulate localization, turnover, and translation. Although high-throughput experiments indicate that many RNA-binding proteins (RBPs) also bind 5' UTRs, much less is known about specific post-transcriptional control exerted by 5' UTRs. GLD-1 is a conserved RBP and a translational repressor with essential roles in Caenorhabditis elegans germ cell development. Previously, we showed that GLD-1 binds highly conserved sites in both 3' and 5' UTRs. Here, by targeted single-copy insertion of transgenes, we systematically tested in vivo functionality of 5' and 3' UTR binding sites individually and in combination. Our data show that sites in 5' UTRs mediate specific and strong translational repression, independent of exact position. Intriguingly, we found that the functionality of 3' UTR sites can be masked by 5' UTR sites and vice versa. We conclude that it is important to study both UTRs simultaneously
Ethische Kompetenz im Rettungsdienst: Ausbildung professioneller Helfer - Ergebnisse einer Interviewstudie in Basel
Zusammenfassung: Fragestellung: Ziel der Studie war es, die ethischen Dimensionen von Reanimationsentscheidungen im Rettungsdienst zu untersuchen. Methode: Ein qualitatives Studiendesign wurde entwickelt, um ethische Entscheidungskriterien, persönliche Wertvorstellungen und Bedarf an Aus- und Weiterbildung zu erfragen. Mit Rettungsdienstmitarbeitern in Basel wurden 30 strukturierte Interviews geführt und nach der qualitativen Inhaltsanalyse ausgewertet. Ergebnisse: Notärzte und Rettungssanitäter beziehen eine Vielzahl ethischer Überlegungen in ihre Entscheidungen mit ein. Die Mehrheit äußerte Interesse an ethischer Schulung oder forderte sogar eine stärkere Verankerung ethischer Inhalte in Aus- und Weiterbildung. Schlussfolgerung: Konzepte für die Vermittlung medizinischer Ethik sollten den Bedürfnissen professioneller Helfer und den besonderen Gegebenheiten des Rettungsdienstes Rechnung trage
Dynamic rotor mode in antiferromagnetic nanoparticles
We present experimental, numerical, and theoretical evidence for a new mode
of antiferromagnetic dynamics in nanoparticles. Elastic neutron scattering
experiments on 8 nm particles of hematite display a loss of diffraction
intensity with temperature, the intensity vanishing around 150 K. However, the
signal from inelastic neutron scattering remains above that temperature,
indicating a magnetic system in constant motion. In addition, the precession
frequency of the inelastic magnetic signal shows an increase above 100 K.
Numerical Langevin simulations of spin dynamics reproduce all measured neutron
data and reveal that thermally activated spin canting gives rise to a new type
of coherent magnetic precession mode. This "rotor" mode can be seen as a
high-temperature version of superparamagnetism and is driven by exchange
interactions between the two magnetic sublattices. The frequency of the rotor
mode behaves in fair agreement with a simple analytical model, based on a high
temperature approximation of the generally accepted Hamiltonian of the system.
The extracted model parameters, as the magnetic interaction and the axial
anisotropy, are in excellent agreement with results from Mossbauer
spectroscopy
Økologiske søer overforsynes med protein - også om vinteren
Økologiske og andre udendørs svin overforsynes i dag med
protein, fordi de fodres efter de samme fodringsstrategier som indendørs svin, hvor der ikke tages hensyn til højere foderstyrke og til næringsstofforsyningen fra grovfoderet
Transcriptome-wide analysis of regulatory interactions of the RNA-binding protein HuR
Posttranscriptional gene regulation relies on hundreds of RNA binding proteins (RBPs) but the function of most RBPs is unknown. The human RBP HuR/ELAVL1 is a conserved mRNA stability regulator. We used PAR-CLIP, a recently developed method based on RNA-protein crosslinking, to identify transcriptome-wide ~26,000 HuR binding sites. These sites were on average highly conserved, enriched for HuR binding motifs and mainly located in 3' untranslated regions. Surprisingly, many sites were intronic, implicating HuR in mRNA processing. Upon HuR knockdown, mRNA levels and protein synthesis of thousands of target genes were downregulated, validating functionality. HuR and miRNA binding sites tended to reside nearby but generally did not overlap. Additionally, HuR knockdown triggered strong and specific upregulation of miR-7. In summary, we identified thousands of direct and functional HuR targets, found a human miRNA controlled by HuR, and propose a role for HuR in splicing
Magnetoresistance of a 2-dimensional electron gas in a random magnetic field
We report magnetoresistance measurements on a two-dimensional electron gas
(2DEG) made from a high mobility GaAs/AlGaAs heterostructure, where the
externally applied magnetic field was expelled from regions of the
semiconductor by means of superconducting lead grains randomly distributed on
the surface of the sample. A theoretical explanation in excellent agreement
with the experiment is given within the framework of the semiclassical
Boltzmann equation.Comment: REVTEX 3.0, 11 pages, 3 Postscript figures appended. The manuscript
can also be obtained from our World Wide Web server:
http://roemer.fys.ku.dk/randmag.ht
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