Microtubule movements on the arms of mitotic chromosomes: polar ejection forces quantified in vitro.

ABSTRACT: During mitosis, "polar ejection forces" (PEFs) are hypothesized to direct prometaphase chromosome movements by pushing chromosome arms toward the spindle equator. PEFs are postulated to be caused by (i) plus-end-directed microtubule (MT)-based motor proteins on the chromosome arms, namely chromokinesins, and (ii) the polymerization of spindle MTs into the chromosome. However, the exact role of PEFs is unclear, because little is known about their magnitude or their forms (e.g., impulsive vs. sustained, etc.). In this study, we employ optical tweezers to bring about the lateral interaction between chromosome arms and MTs in vitro to directly measure the speed and force of the PEFs developed on chromosome arms. We find that forces are unidirectional and frequently exceed 1 pN, with maximum fo

SUBMITTER: Brouhard GJ 

PROVIDER: S-EPMC1236563 | biostudies-literature | 2005 Sep

REPOSITORIES: biostudies-literature