title: Differences in centromere positioning of cycling and postmitotic human cell types.
abstract: Centromere positioning in human cell nuclei was traced in non-cycling peripheral blood lymphocytes (G0) and in terminally differentiated monocytes, as well as in cycling phytohemagglutinin-stimulated lymphocytes, diploid lymphoblastoid cells, normal fibroblasts, and neuroblastoma SH-EP cells using immunostaining of kinetochores, confocal microscopy and three-dimensional image analysis. Cell cycle stages were identified for each individual cell by a combination of replication labeling with 5-bromo-2'-deoxyuridine and immunostaining of pKi67. We demonstrate that the behavior of centromeres is similar in all cell types studied: a large fraction of centromeres are in the nuclear interior during early G1; in late G1 and early S phase, centromeres shift to the nuclear periphery and fuse in clusters. Peripheral location and clustering of centromeres are most pronounced in non-cycling cells (G0) and terminally differentiated monocytes. In late S and G2, centromeres partially decluster and migrate towards the nuclear interior. In the rather flat nuclei of adherently growing fibroblasts and neuroblastoma cells, kinetochores showed asymmetrical distributions with preferential kinetochore location close either to the bottom side of the nucleus (adjacent to the growth surface) or to the nuclear upper side. This asymmetrical distribution of centromeres is considered to be a consequence of chromosome arrangement in anaphase rosettes.
authors.affiliation: Department of Biology II, Humangenetik, Ludwig Maximillians University (LMU), Richard Wagner Str. 10, 80333, Munich, Germany. irina.solovei@lrz.uni-muenchen.de
authors.forename: Irina
authors.initials: I
authors.lastname: Solovei
authors.forename: Lothar
authors.initials: L
authors.lastname: Schermelleh
authors.forename: Klaus
authors.initials: K
authors.lastname: Düring
authors.forename: Andrea
authors.initials: A
authors.lastname: Engelhardt
authors.forename: Stefan
authors.initials: S
authors.lastname: Stein
authors.forename: Christoph
authors.initials: C
authors.lastname: Cremer
authors.forename: Thomas
authors.initials: T
authors.lastname: Cremer
mesh_terms: D001973:Bromodeoxyuridine; D002453:Cell Cycle / Q000235:genetics*; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000235:genetics*; D002503:Centromere / Q000235:genetics*; D004261:DNA Replication; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D008214:Lymphocytes / Q000166:cytology*; D008938:Mitosis / Q000235:genetics*; D009000:Monocytes / Q000166:cytology; D009447:Neuroblastoma / Q000473:pathology
chemical_list: D001973:Bromodeoxyuridine