The centromere-kinetochore complex: a repeat subunit model.
Open Access
- 1 June 1991
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 113 (5), 1091-1110
- https://doi.org/10.1083/jcb.113.5.1091
Abstract
The three-dimensional structure of the kinetochore and the DNA/protein composition of the centromere-kinetochore region was investigated using two novel techniques, caffeine-induced detachment of unreplicated kinetochores and stretching of kinetochores by hypotonic and/or shear forces generated in a cytocentrifuge. Kinetochore detachment was confirmed by EM and immunostaining with CREST autoantibodies. Electron microscopic analyses of serial sections demonstrated that detached kinetochores represented fragments derived from whole kinetochores. This was especially evident for the seven large kinetochores in the male Indian muntjac that gave rise to 80-100 fragments upon detachment. The kinetochore fragments, all of which interacted with spindle microtubules and progressed through the entire repertoire of mitotic movements, provide evidence for a subunit organization within the kinetochore. Further support for a repeat subunit model was obtained by stretching or uncoiling the metaphase centromere-kinetochore complex by hypotonic treatments. When immunostained with CREST autoantibodies and subsequently processed for in situ hybridization using synthetic centromere probes, stretched kinetochores displayed a linear array of fluorescent subunits arranged in a repetitive pattern along a centromeric DNA fiber. In addition to CREST antigens, each repetitive subunit was found to bind tubulin and contain cytoplasmic dynein, a microtubule motor localized in the zone of the corona. Collectively, the data suggest that the kinetochore, a plate-like structure seen by EM on many eukaryotic chromosomes is formed by the folding of a linear DNA fiber consisting of tandemly repeated subunits interspersed by DNA linkers. This model, unlike any previously proposed, can account for the structural and evolutional diversity of the kinetochore and its relationship to the centromere of eukaryotic chromosomes of many species.Keywords
This publication has 52 references indexed in Scilit:
- Distribution of non-telomeric sites of the (TTAGGG)n telomeric sequence in vertebrate chromosomesChromosoma, 1990
- Ciliary microtubule capping structures contain a mammalian kinetochore antigen.The Journal of cell biology, 1990
- The motor for poleward chromosome movement in anaphase is in or near the kinetochore.The Journal of cell biology, 1989
- Conservation of the human telomere sequence (TTAGGG)n among vertebrates.Proceedings of the National Academy of Sciences, 1989
- Alphoid satellite DNA is tightly associated with centromere antigens in human chromosomes throughout the cell cycleExperimental Cell Research, 1989
- Tubulin interaction with kinetochore proteins: analysis by in vitro assembly and chemical cross-linking.The Journal of cell biology, 1987
- Properties of the kinetochore in vitro. I. Microtubule nucleation and tubulin binding.The Journal of cell biology, 1985
- Caffeine alone causes DNA damage in Chinese hamster ovary cells.Cell Structure and Function, 1985
- Microtubule initiation at kinetochores and centrosomes in lysed mitotic cells. Inhibition of site-specific nucleation by tubulin antibody.The Journal of cell biology, 1979
- Fine structure of kinetochore in Indian muntjacExperimental Cell Research, 1971