Instead, Bub3, together with Bub1, has a specific function in promoting the conversion from chromosome mono-orientation to bi-orientation.
Therefore, we suggest that Bub1 and Bub3 together have a Sgo2-independent role in promoting the conversion from chromosome mono-orientation to bi-orientation.
Little is known about the molecular events that occur during conversion from chromosome mono-orientation to bi-orientation in any organism.
In fission yeast, deletion of the dynein heavy chain (dhc1) causes a defect in the transition from chromosome mono-orientation to bi-orientation that resembles that seen in bub3Δ cells (Grishchuk et al, 2007).
Cells expressing the bub1-Δ GLEBS mutant showed a defect in converting chromosome mono-orientation to bi-orientation that was similar to bub3Δ cells (Fig 3B D; supplementary Fig S4E online).
To test whether the role of Bub3 in promoting the conversion from mono-orientation to bi-orientation is shared with its interaction partner Bub1, we assayed chromosome segregation under similar conditions using a specific bub1 mutant (bub1-Δ GLEBS), which lacks the Bub3-interacting region (Larsen et al, 2007).
Our results therefore suggest that Bub3 is involved in converting the mono-orientation of chromosomes to bi-orientation.
When bub3 was deleted in addition to sgo2, mono-orientation was prolonged, similar to the bub3Δ single mutant (Fig 3B,D; supplementary Fig S4G online), making it unlikely that Sgo2 acts downstream of Bub3 in promoting chromosome bi-orientation.
KCC team orientation to licensing.
Change the slide orientation to portrait.
Test orientation to time (5 points).
