Figure 5.

Rif Localizes to Anaphase Mid-region

(A) Frames from films of WT cells at 32°C or taz1Δ cells grown to log phase at 32°C and then shifted to 19°C for 24 hr. Rif1 is N-terminally GFP-tagged under nmt41 promoter control and histone H3 tagged as in Figure 1. GFP-Rif1 lingers in the mid-region as cells complete anaphase. Compare with Figure S4E.

(B) Quantitation of GFP-Rif1 stretches during WT-like or aberrant chromosome segregation in taz1Δ cells.

(C) SIM of GFP-Rif1 in anaphase. For each panel, the image is rotated to the orientation that yields the clearest signal. The pattern suggests interlocking helical strands (diagram below).

(D) Cells with either an extra copy of the gene encoding α-tubulin (atb2+, under nmt1 control) or Rif1 tagged as in (A) were grown at 32°C and mixed in one microscope dish. Anaphase, as detected via the presence of a mitotic spindle or two segregating nuclei harboring GFP-Rif1, was filmed. At time point 0’, MBC was added and cells were imaged every 2 min to follow MBC-induced spindle depolymerization. Dissipation of the Atb2 signal (i.e., the spindle) is clearly seen; nonetheless, GFP-Rif1 in adjacent cells (subject to identical MBC treatment in the same dish) clearly persists in the mid-region (red arrow).

See also Figure S4.