A permeabilized cell model for studying cell division: a comparison of anaphase chromosome movement and cleavage furrow constriction in lysed PtK1 cells.

Abstract

After lysis in a Brij 58-polyethylene glycol medium, [rat kangaroo kidney] PtK1 cells are permeable to small molecules, such as erythrosin B, and to proteins, such as rhodamine-labeled FAB [antigen binding fragments], myosin subfragment-1 and tubulin. Holes are present in the plasma membrane, and the mitochondria are swollen and distorted, but other membrane-bounded organelles of the lysed cell model are not noticeably altered. 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. Addition of crude tubulin extracts, MAP[microtubule-associated protein]-free tubulin, or taxol to the lysis medium retards anaphase chromosome movements but does not affect cleavage. N-ethylmaleimide-modified myosin subfragment-1, phalloidin and cytochalasin B inhibit cleavage but have no effect on anaphase chromosome movements under identical lysis conditions. Apparently actomyosin plays no functional role in anaphase chromosome movement in mammalian tissue culture cells and microtubule depolymerization is a rate-limiting step for chromosome-to-pole movements.