Chromosomes move poleward in anaphase along stationary microtubules that coordinately disassemble from their kinetochore ends.

摘要: During the movement of chromosomes in anaphase, microtubules that extend between kinetochores and poles shorten. We sought to determine where subunits are lost from these during their shortening. Prophase or prometaphase cells on coverslips were injected with fluoresceinated tubulin allowed progress through mitosis. Immediately after onset a bar-shaped beam laser light was used mark domain kinetochore fibers by photobleaching band, approximately 1.0 micron wide, across spindle. In different cells, spindles photobleached at varying distances chromosomes. Cells continue anaphase until had further separated. They then lysed, fixed, prepared for double-label immunofluorescence an antibody fluorescein does not bind appreciably bleached fluorescein, tubulin. Photobleached domains appeared as bands reduced fluorescence anti-fluorescein image. However, anti-tubulin labeling revealed present continuous domains. all cases, approached invaded while itself remained stationary respect near pole. These results demonstrate move along depolymerization takes place kinetochore. contrast generally accepted older view passive objects pulled "traction fibers," we suggest is active participant generating motive force propels chromosome