Skip to main content
. 2000 Jul 24;150(2):361–376. doi: 10.1083/jcb.150.2.361

Figure 6.

Figure 6

Cytoplasmic dynein powers microtubule gliding, aster expansion, and F-actin bundle jerking. (A) Low magnification, time-lapse views of microtubules (left) seeded from a demembranated Xenopus sperm and F-actin (right) in the presence of 2 mg/ml anti-cytoplasmic dynein intermediate chain antibody 70.1. The antibody inhibits the translocation of microtubules away from the MTOC, thus inhibiting aster expansion but does not inhibit microtubule nucleation and growth, thus inducing a striking accumulation of microtubules (left; compare to Fig. 2 B). The antibody also inhibits F-actin jerking and prevents centrifugal clearing of F-actin from the aster (right). Time is in min/s. (B) Low magnification views showing asters that were fixed at various times after the addition of demembranated sperm to Xenopus extracts in solution in the presence of 2 mg/ml anti-cytoplasmic dynein intermediate chain antibody 70.1. In the presence of the antibody, even at late time points, the aster remains tightly focussed and has many microtubules emanating from it (compare to Fig. 2 C). (C) Cytoplasmic dynein activity is required for microtubule gliding. Quantification of the rate of microtubule gliding across the substrate was calculated in control extracts (n = 11), extracts containing 2 mg/ml 70.1 (n = 9), and extracts containing 250 μM sodium orthovanadate (n = 5). Inhibition of cytoplasmic dynein drastically slowed the rate of microtubule gliding. (D) Cytoplasmic dynein activity is required for F-actin jerking. Quantification of the rate of F-actin jerking was determined from the same experiments used for C. Inhibition of cytoplasmic dynein with 70.1 antibodies or orthovanadate completely eliminated F-actin jerking. (E) Cytoplasmic dynein is not required for F-actin zippering. Quantification of the rate of F-actin zippering was determined from the same experiments used for C. Cytoplasmic dynein inhibition with 70.1 antibodies or orthovanadate does not affect F-actin zippering. Also see supplemental video 11 at http://www.jcb.org/cgi/content/full/150/2/361/DC1.