Project description:Mitotic chromosomes in different organisms adopt various dimensions. What defines chromosome dimensions is scarcely understood. Here, we compare budding and fission yeasts that harbor similarly sized genomes distributed amongst 16 or 3 chromosomes, respectively. Budding yeast chromosomes are thinner and characterized by shorter mitotic chromatin interactions. This remains the case even following chromosome fusions to form three fission-yeast-length entities, revealing a species-specific organizing principle that correlates with condensin binding site spacing. Unexpectedly, within each species, longer chromosome arms are always thicker, a trend also observed with human chromosomes. Arm length as a chromosome width determinant informs mitotic chromosome formation models.
Project description:Hrp3_Purification from Schizosaccharomyces pombe 972h- Eukaryotic genome is composed of repeating units of nucleosomes to form chromatin arrays. A canonical gene is marked by nucleosome free region (NFR) at its 5’ end followed by uniformly spaced arrays of nucleosomes. In fission yeast we show both biochemically and in vivo that both Hrp1 and Hrp3 are key determinants of uniform spacing of genic arrays.
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
