Figure 4
From: Kar9 symmetry breaking alone is insufficient to ensure spindle alignment
Swe1 acts to regulate symmetry breaking independently of the Cdk1-Kar9 pathway. (a, inset) swe1∆ cells display increased asymmetry in the population relative to WT. (a) Deletion of Swe1 results in early symmetry breaking. (b, inset). Deletion of Swe1 partially rescues the symmetry breaking defect in the kar9-AA population. (b) Symmetry breaking occurs at random in the double mutant. (c) Asymmetric swe1∆ cells are biased toward alignment but are less efficient that WT asymmetric cells. (d) Asymmetric cells in the double mutant population are broadly distributed along a large range of AI values indicating a poor ability to align themselves. (e) Cumulative percentage of PA spindles in asymmetric populations as a function of increasing spindle length, which is a proxy for time spent in metaphase. Over time, WT asymmetric spindles achieve perfect alignment more efficiently than the swe1∆ mutant and swe1∆; kar9-AA double mutant. A small population of PA asymmetric kar9-AA cells emerges later in metaphase. (f) The correlation between perfect alignment and asymmetry is reduced in the swe1∆ mutant relative to WT. The swe1∆; kar9-AA double mutant behaves similarly to kar9-AA.
