title: Shaping mitotic chromosomes: From classical concepts to molecular mechanisms.
abstract: How eukaryotic genomes are packaged into compact cylindrical chromosomes in preparation for cell divisions has remained one of the major unsolved questions of cell biology. Novel approaches to study the topology of DNA helices inside the nuclei of intact cells, paired with computational modeling and precise biomechanical measurements of isolated chromosomes, have advanced our understanding of mitotic chromosome architecture. In this Review Essay, we discuss - in light of these recent insights - the role of chromatin architecture and the functions and possible mechanisms of SMC protein complexes and other molecular machines in the formation of mitotic chromosomes. Based on the information available, we propose a stepwise model of mitotic chromosome condensation that envisions the sequential generation of intra-chromosomal linkages by condensin complexes in the context of cohesin-mediated inter-chromosomal linkages, assisted by topoisomerase II. The described scenario results in rod-shaped metaphase chromosomes ready for their segregation to the cell poles.
authors.affiliation: European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Kschonsak
authors.affiliation: European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
authors.forename: Christian H
authors.initials: CH
authors.lastname: Haering
mesh_terms: D000251:Adenosine Triphosphatases / Q000502:physiology; D000818:Animals; D042002:Chromatin Assembly and Disassembly; D002875:Chromosomes / Q000502:physiology / Q000648:ultrastructure*; D004268:DNA-Binding Proteins / Q000502:physiology; D006801:Humans; D008938:Mitosis; D046912:Multiprotein Complexes / Q000502:physiology; D009707:Nucleosomes / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009707:Nucleosomes; C108312:condensin complexes; D000251:Adenosine Triphosphatases
keywords: SMC complex; chromosome condensation; chromosome segregation; cohesin; condensin; mitosis; topoisomerase II