Structure of the histone mRNA hairpin required for cell cycle regulation of histone gene expression.

Expression of replication-dependent histone genes requires a conserved hairpin RNA element in the 3' untranslated regions of poly(A)-less histone mRNAs. The 3' hairpin element is recognized by the hairpin-binding protein or stem-loop-binding protein (HBP/SLBP). This protein-RNA interaction is important for the endonucleolytic cleavage generating the mature mRNA 3' end. The 3' hairpin and presumably HBP/SLBP are also required for nucleocytoplasmic transport, translation, and stability of histone mRNAs. RNA 3' processing and mRNA stability are both regulated during the cell cycle. Here, we have determined the three-dimensional structure of a 24-mer RNA comprising a mammalian histone RNA hairpin using heteronuclear multidimensional NMR spectroscopy. The hairpin adopts a novel UUUC tetraloop conformation that is stabilized by base stacking involving the first and third loop uridines and a closing U-A base pair, and by hydrogen bonding between the first and third uridines in the tetraloop. The HBP interaction of hairpin RNA variants was analyzed in band shift experiments. Particularly important interactions for HBP recognition are mediated by the closing U-A base pair and the first and third loop uridines, whose Watson-Crick functional groups are exposed towards the major groove of the RNA hairpin. The results obtained provide novel structural insight into the interaction of the histone 3' hairpin with HBP, and thus the regulation of histone mRNA metabolism.

The Caenorhabditis elegans histone hairpin-binding protein is required for core histone gene expression and is essential for embryonic and postembryonic cell division.

As in all metazoans, the replication-dependent histone genes of Caenorhabditis elegans lack introns and contain a short hairpin structure in the 3' untranslated region. This hairpin structure is a key element for post-transcriptional regulation of histone gene expression and determines mRNA 3' end formation, nuclear export, translation and mRNA decay. All these steps contribute to the S-phase-specific expression of the replication-dependent histone genes. The hairpin structure is the binding site for histone hairpin-binding protein that is required for hairpin-dependent regulation. Here, we demonstrate that the C. elegans histone hairpin-binding protein gene is transcribed in dividing cells during embryogenesis and postembryonic development. Depletion of histone hairpin-binding protein (HBP) function in early embryos using RNA-mediated interference leads to an embryonic-lethal phenotype brought about by defects in chromosome condensation. A similar phenotype was obtained by depleting histones H3 and H4 in early embryos, indicating that the defects in hairpin-binding protein-depleted embryos are caused by reduced histone biosynthesis. We have confirmed this by showing that HBP depletion reduces histone gene expression. Depletion of HBP during postembryonic development also results in defects in cell division during late larval development. In addition, we have observed defects in the specification of vulval cell fate in animals depleted for histone H3 and H4, which indicates that histone proteins are required for cell fate regulation during vulval development.

Fünf Jahre im Lande Neutralien : Schweizer Kriegserlebnisse eines jüdischen Schriftstellers

von Sch. Gorelik. (Dt. von Nadja Strasser)

Caput I - V

Enth.: 1. Die Wiener Märtyrer. 2. Die symbolischen Bücher. 3. Traumbuch für Michel. 4. Eljen Kossuth! 5. Apostel und Apostaten

Warum sind die 200 ungarischen Reichstagsdeputirten in Wien? Wer die Geschichte der österreichischen Völker eine Strecke weit zurückverfolgt ...

Welsch (Projektbearbeiter): Aufruf zur Versöhnung zwischen Kroaten und Ungarn anläßlich des bevorstehenden Zusammentreffens einer ungarischen Reichstagsdeputation mit ihrem König Ferdinand V. in Wien

Der Teufel im Reichstag oder Wer soll Minister werden? Der Kaiser hat einen konstituirenden Reichstag zusammengesetzt ...

Welsch (Projektbearbeiter): Der Reichstag hört auf, ein konstituierender zu sein, wenn das Ministerium sich in dem Ausmaß in das legislative parlamentarische Verfahren einmischt, wie es beim Kudlichschen Antrag der Fall war. Aus anfangs liberalen und sogar radikalen Ministern wie Doblhoff und Schwarzer wurden "Höflinge", weswegen "ein freier Mann, der seine Gesinnung beibehalten will" nicht Minister werden sollte

National-Theater: Die schlechte Auführung [sic!], 1. Act, darauf folgt Die Versöhnung: Musick: War denn je ein Mensch so frech als wie: Fürst von Haggern: Das ist frech ...

Welsch (Projektbearbeiter): Karikatur auf die sich in kleinlichen Streitigkeiten verzettelnde Frankfurter Nationalversammlung am Beispiel einer Auseinandersetzung zwischen dem Präsidenten Gagern und dem Abgeordneten Rösler

Wahlkampf im Burgfrieden

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Das Echo der alldeutschen Bewegung in Amerika [Rezension]

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Wieder ein deutschfeindlicher Jude!

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Friede auf Erden [Rezension]

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Antisemitische Vorstöße im hessischen Landtag

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Jahrbuch für jüdische Geschichte und Literatur [Rezension]

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Die internationale Wirksamkeit des Judentums in der Vergangenheit und in der Zukunft [Rezension]

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