Thesis (M.Sc.)--University of Toronto, 1990.
|Series||Canadian theses = Thèses canadiennes|
|The Physical Object|
By simultaneously imaging chromosomes (or kinetochores) and flux, we provide evidence that flux is the dominant mechanism driving chromosome-to-pole movement (anaphase A) in these spindles. A unique tubulin antiserum inhibits poleward chromosome movement in anaphase [microform]. Mitotic PtK1 cells, lysed at anaphase into a carbowax 20 M Brij 58 solution, continue to move chromosomes toward the spindle poles and to move the spindle poles apart at 50% in . The tubulin-binding agent ZD is a novel vascular-targeting agent in clinical development for the treatment of solid tumors. In vivo, ZD is rapidly converted into N-acetylcolchinol (ZD
After lysis, the mitotic apparatus is functional; chromosomes move poleward and the spindle elongates. Cells lysed while in cytokinesis will continue to divide for several minutes. Chromosome movement during anaphase is the result of all of the following except a. the hydrolysis of ATP by motor proteins (dynein). b. molecular motors at the kinetochores that move the chromosomes toward the poles. c. molecular motors at the centrosome that pull the microtubules toward the poles. D. Microtubule-dependent motor proteins and microtubule polymerization and depolymerization are mainly responsible for the organized movements of chromosomes during mitosis. E. The centromere nucleates a radial array of microtubules called an aster, and its duplication is triggered by S-Cdk. F. a) The location of the centromere is unique for each chromosome. b) Some spindle fibers become attached to kinetochores. c) The spindle apparatus is composed of protein molecules of tubulin. d) Some microtubules overlap at the spindle equator. e) All of these are NOT true.
A unique tubulin antiserum attenuates the rate of poleward chromosome movement in anaphase. Eur J Cell Biol. Aug; 58 (2)– Gorbsky GJ, Sammak PJ, Borisy GG. Chromosomes move poleward in anaphase along stationary microtubules that coordinately disassemble from their kinetochore ends. J Cell Biol. Jan; (1):9– The axial ratio of a spindle was determined by dividing its width by its length during metaphase (20 s before anaphase A onset when kinetochores start to move poleward), anaphase A (20 s before the end of anaphase A, when all kinetochores reach opposite poles), and anaphase B (20 s after the end of anaphase . Kif2a disassembles microtubules at their minus ends at spindle poles in association with poleward microtubule flux, and this activity makes a small contribution to poleward chromosome movement in anaphase (Ganem et al., ). In contrast to MCAK and Kif2a, the function of the remaining member of the kinesin family, Kif2b, has not been explored. A pole matrix component such as NuMA could provide sufficient mechanical stability by tethering parallel microtubule bundles. It could further explain the finding that spindles from which the centrosomes have been experimentally severed remain mechanically stable and even undergo poleward chromosome movement during anaphase (27, 26).Cited by: