Politikwissenschaftsstudierende und der 1. Mai 2004:Eine empirische Untersuchung zu Informiertheit, Wissen und Meinung von Hochschülern der Westfälischen Wilhelms-Universität Münster zur Osterweiterung der Europäischen Union

Seminar: Am Anfang steht das Problem: Einführung in die Durchführung empirischer Studien. Sommersemester 2004Dozentin: Susanne in der Smitten Forschungsprojekt im Rahmen der empirischen Sozialforschung Erstellungszeitraum: 19. April 2004 - 04. August 2004 Durchgeführt von: Martin Biederstedt, Dominik Bulla, Johanna Keifenheim, Maria Schröder, David Schulke</div

Cell cycle responses to Topoisomerase II inhibition: Molecular mechanisms and clinical implications.

DNA Topoisomerase IIA (Topo IIA) is an enzyme that alters the topological state of DNA and is essential for the separation of replicated sister chromatids and the integrity of cell division. Topo IIA dysfunction activates cell cycle checkpoints, resulting in arrest in either the G2-phase or metaphase of mitosis, ultimately triggering the abscission checkpoint if non-disjunction persists. These events, which directly or indirectly monitor the activity of Topo IIA, have become of major interest as many cancers have deficiencies in Topoisomerase checkpoints, leading to genome instability. Recent studies into how cells sense Topo IIA dysfunction and respond by regulating cell cycle progression demonstrate that the Topo IIA G2 checkpoint is distinct from the G2-DNA damage checkpoint. Likewise, in mitosis, the metaphase Topo IIA checkpoint is separate from the spindle assembly checkpoint. Here, we integrate mechanistic knowledge of Topo IIA checkpoints with the current understanding of how cells regulate progression through the cell cycle to accomplish faithful genome transmission and discuss the opportunities this offers for therapy

Size-Dependent Expression of the Mitotic Activator Cdc25 Suggests a Mechanism of Size Control in Fission Yeast

Proper cell size is essential for cellular function. Nonetheless, despite more than 100 years of work on the subject, the mechanisms that maintain cell-size homeostasis are largely mysterious [ 1 ]. Cells in growing populations maintain cell size within a narrow range by coordinating growth and division. Bacterial and eukaryotic cells both demonstrate homeostatic size control, which maintains population-level variation in cell size within a certain range and returns the population average to that range if it is perturbed [ 1, 2 ]. Recent work has proposed two different strategies for size control: budding yeast has been proposed to use an inhibitor-dilution strategy to regulate size at the G1/S transition [ 3 ], whereas bacteria appear to use an adder strategy, in which a fixed amount of growth each generation causes cell size to converge on a stable average [ 4–6 ]. Here we present evidence that cell size in the fission yeast Schizosaccharomyces pombe is regulated by a third strategy: the size-dependent expression of the mitotic activator Cdc25. cdc25 transcript levels are regulated such that smaller cells express less Cdc25 and larger cells express more Cdc25, creating an increasing concentration of Cdc25 as cells grow and providing a mechanism for cells to trigger cell division when they reach a threshold concentration of Cdc25. Because regulation of mitotic entry by Cdc25 is well conserved, this mechanism may provide a widespread solution to the problem of size control in eukaryotes

Comparative functional genomics of the fission yeasts

The fission yeast clade--comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus, and S. japonicus--occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, which suggests a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the budding yeast of Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade

Politikwissenschaftsstudierende und der 1. Mai 2004:Eine empirische Untersuchung zu Informiertheit, Wissen und Meinung von Hochschülern der Westfälischen Wilhelms-Universität Münster zur Osterweiterung der Europäischen Union

Seminar: Am Anfang steht das Problem: Einführung in die Durchführung empirischer Studien. Sommersemester 2004Dozentin: Susanne in der Smitten Forschungsprojekt im Rahmen der empirischen Sozialforschung Erstellungszeitraum: 19. April 2004 - 04. August 2004 Durchgeführt von: Martin Biederstedt, Dominik Bulla, Johanna Keifenheim, Maria Schröder, David Schulke</div