The Kinetochore Protein Kis1/Eic1/Mis19 Ensures the Integrity of Mitotic Spindles through Maintenance of Kinetochore Factors Mis6/CENP-I and CENP-A
Figure 3
kis1-1 has defects in spindle formation.
Cells expressing GFP-Atb2 (marks microtubules), Cnp3-tdTomato (marks kinetochore), and Sid4-CFP (marks SPB) (A,B,D,E) and cells expressing Sfi1-GFP (C,F) in the indicated background were grown at 25°C, followed by a temperature shift to 36°C for 6–9 h. (A) Fluorescence intensity of the middle region of the metaphase spindle in kis1-1 was dimmer than that in the wild-type (WT) strain. Left: The spindle was divided into three parts: the “middle” zone, the left “pole”, and right “pole.” The region outlined in each of the WT and kis1-1 images, which shows the GFP-Atb2 signal, is magnified below each image. Right: The ratio of the “middle” GFP intensity to the “pole” intensity of spindles observed under the indicated conditions. *p<0.05 (Student's t-test); n.s., not significant (p>0.05). (B–F) Mitotic progression of WT and kis1-1 cells. Kinetics of the inter-SPB distance in each of WT (C) and in kis1-1 (F) are shown graphically. (D,E) kis1-1 cells showed mainly two types of spindle defects: type 1, weak GFP-Atb2–staining midzone (D); and type 2, defects in spindle elongation (E). Scale bars: 5 µm except magnified images in A (1 µm).
