Dynein regulates microtubule dynamics. (A) Time series images of GFP-Tub1 in a dynein-null cell in pre-anaphase to indicate microtubule dwell time at the cell cortex. A time scale (seconds) is shown below each image. Bar, 1 µm. (B) Median frequency of microtubule plus-end cortical interactions per minute. WT, n = 34 cells; dyn1Δ, n = 59; num1Δ, n = 56; nip100Δ, n = 30. Error bars are 95% c.i. (C) Median percent time with the microtubule plus end at the cell cortex. WT, n = 28 cells; dyn1Δ, n = 38; num1Δ, n = 31; nip100Δ, n = 20. Error bars are 95% c.i. (D) Representative images of microtubules labeled with GFP-Tub1 in pre-anaphase cells of the indicated genotypes. Arrowheads point to astral microtubules. Each image is a maximum intensity projection from a confocal Z series. Bars, 1 µm. (E) Median astral microtubule length in pre-anaphase cells at 25 and 37°C. 25°C: WT, n = 341 microtubules; dyn1Δ, n = 278; tub2-430Δ, n = 152. 37°C: tub2-430Δ and td-dyn1Δ, n = 46; dyn1Δ, n = 60; WT, n = 62. Error bars are 95% c.i. aMT, astral microtubule. (F) Median astral microtubule length in galactose. OE-DYN1, n = 343; native, n = 399; dyn1Δ, n = 221. Error bars are 95% c.i. (G) Representative life plots displaying the lengths of single microtubules over time. Arrows point to catastrophe events. (H) Mean dynamicity displayed in tubulin subunits per second. WT, n = 68 growth or shrinkage events; dyn1Δ, n = 47; OE-DYN1, n = 49. Error bars are SEM. Asterisks denote a significant difference from WT. *, P < 0.05; **, P < 0.005; ***, P < 0.0006; ****, P < 0.0001; determined by t test.