Figure 7.

Spindle pole formation in wild-type and mutant plants. For each genotype a time course was done to look at the early events of spindle pole formation, starting at preprophase and ending at early prometaphase. In ATK1/ATK1 plants at t = 20 s, the perinuclear microtubule array dims in the region proximal to the PPB, and a clearing is observed at t = 40 s (boxed region). Furthermore, there is a concomitant increase in microtubules at the spindle poles (sp), and by t = 60 s, the microtubules emanating from the poles have extended into the clearing zone along the perinuclear array. In the mutant genotypes at t = 40 s, microtubule clearing in the region of the perinuclear array that is proximal to the PPB is not seen (boxed region) and microtubule localization is not increasing at the spindle poles (sp), but is in other areas along the perinuclear array. This continues at t = 60 s, though microtubules also appear in the nucleus. Scale bar, 10 μm.