Title | Direct kinetochore-spindle pole connections are not required for chromosome segregation. |
Publication Type | Journal Article |
Year of Publication | 2014 |
Authors | Sikirzhytski V, Magidson V, Steinman JB, He J, Le Berre M, Tikhonenko I, Ault JG, McEwen BF, Chen JK, Sui H, Piel M, Kapoor TM, Khodjakov A |
Journal | J Cell Biol |
Volume | 206 |
Issue | 2 |
Pagination | 231-43 |
Date Published | 2014 Jul 21 |
ISSN | 1540-8140 |
Keywords | Anaphase, Animals, Cells, Cultured, Chromosome Segregation, Chromosomes, Humans, Kinetochores, Marsupialia, Metaphase, Microtubules, Spindle Poles |
Abstract | Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes' kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells. |
DOI | 10.1083/jcb.201401090 |
Alternate Journal | J. Cell Biol. |
PubMed ID | 25023516 |
PubMed Central ID | PMC4107786 |
Grant List | R01 GM101026 / GM / NIGMS NIH HHS / United States R01 GM059363 / GM / NIGMS NIH HHS / United States P50 GM107615 / GM / NIGMS NIH HHS / United States GM059363 / GM / NIGMS NIH HHS / United States T32 GM007739 / GM / NIGMS NIH HHS / United States |
Submitted by kej2006 on June 6, 2018 - 4:09pm