Functional characterization of Pol5 in the maturation of both ribosomal subunits

Ribosome biogenesis is a complex process. In the yeast Saccharomyces cerevisiae, it requires the concerted action of 79 ribosomal proteins (RPs), more than 150 assembly factors (AFs), four ribosomal RNAs (rRNAs), and several snoRNAs. During the past 50 years, most studies focused on the pathway how ribosomes are synthesized and how this process is regulated. Using multidisciplinary approaches, we know most of the factors involved in the synthesis of ribosomes, the steps in which they participate, and the structure of several ribosomal intermediates. In addition, for several AFs their specific catalytic activities and putative functions have been proposed. Nevertheless, there are many AFs whose function is far from being understood or even weakly related to ribosome synthesis. Among the not well characterized factors, the protein Pol5 was initially described as a B-type like DNA polymerase with a putative role in the assembly of the small ribosomal subunit and in rDNA transcription due to its physical association with proteins participating in these processes. In this study, Pol5 was characterized and it was described as the fourth AF involved in the maturation of both ribosomal subunits. By performing a detailed phenotypic analysis of yeast cells in dependency of Pol5 expression, the role of Pol5 in the initial folding of the polypeptide exit tunnel within the large ribosomal subunit could be defined. In contrast to the published association of Pol5 with AFs involved in the assembly of the small subunit, the data presented in this thesis do not support a stable association of these early assembling proteins under optimal growth conditions. However, Pol5 might play a role in the recycling of several AFs of the small subunit, which is required to maintain an ongoing synthesis of ribosomes. Moreover, part of the N-terminal domain of the protein, and more specifically, a motif participating in the recruitment of the nuclear exosome, is suggested to be involved in the recycling process. Thus, Pol5 might connect the recycling of AFs of the small subunit with the correct assembly of the large subunit. This theory, which is compatible with alternative regulatory pathways, contributes to a rational explanation for the balanced synthesis of both ribosomal subunits in eukaryotic organisms

Bild und Geschlecht in den drei „Religionen des Buches”: Judentum, Christentum, Islam

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.Trotz vieler Gemeinsamkeiten kam und kommt es oft zu Konflikten zwischen den drei „Religionen des Buches” – Judentum, Christentum und Islam. Viele von ihnen machen sich an der Geschlechterordnung fest. Diese ist zwar symbolischer Art, wird aber von allen Seiten nicht nur als gottgegeben, sondern auch als „natürlich” betrachtet. Der Aufsatz versucht, den strukturellen Unterschieden zwischen den symbolischen Geschlechterordnungen in den drei Religionen des Buches nachzugehen und zeigt auf, dass das Verhältnis von Mann und Frau in jeder der drei Religionen nach ganz ähnlichen Muster konstruiert ist wie das jeweilige Verhältnis von Gott und Mensch. Diese Verhältnisse, so wird dargestellt, setzen sich fort im nicht-religiösen Leben und prägen das Verständnis von „Welt”.Peer Reviewe

Defining the protein complex proteome of plant mitochondria

A classical approach, protein separation by two-dimensional blue native/sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was combined with tandem mass spectrometry and up-to-date computer technology to characterize the mitochondrial "protein complex proteome" of Arabidopsis (Arabidopsis thaliana) in so far unrivaled depth. We further developed the novel GelMap software package to annotate and evaluate two-dimensional blue native/sodium dodecyl sulfate gels. The software allows (1) annotation of proteins according to functional and structural correlations (e.g. subunits of a distinct protein complex), (2) assignment of comprehensive protein identification lists to individual gel spots, and thereby (3) selective display of protein complexes of low abundance. In total, 471 distinct proteins were identified by mass spectrometry, several of which form part of at least 35 different mitochondrial protein complexes. To our knowledge, numerous protein complexes were described for the first time (e.g. complexes including pentatricopeptide repeat proteins involved in nucleic acid metabolism). Discovery of further protein complexes within our data set is open to everybody via the public GelMap portal at www.gelmap.de/arabidopsis_mito

Lambda(1520) production in d+Au collisions at RHIC

Recent results of $\Lambda$(1520) resonance production in d+Au collisions at $\sqrt{s_{\rm NN}} =$ 200 GeV are presented and discussed in terms of the evolution and freeze-out conditions of a hot and dense fireball medium. Yields and spectra are compared to results from p+p and Au+Au collisions. The $\Lambda$(1520)/$\Lambda$ ratio in d+Au collisions ratio is consistent with the ratio in p+p collisions. This suggests a short time for elastic interactions between chemical and thermal freeze-out. One can conclude that the interaction volume in d+Au collisions is small.Comment: 4 Pages, 3 figures, conference proceedings Quark Matter 200