FIG 4.

The microtubule cytoskeleton. (A) Microtubule cytoskeleton and nuclear organization in Neurospora crassa and Aspergillus nidulans. Bars = 5 μm. (Courtesy of Rosa M. Ramírez Cota; reprinted with permission.) (B) Microtubule-organizing centers in A. nidulans. Shown is a germling with two mitotic spindles. Microtubules were stained with GFP-tagged alpha tubulin, and the SPBs were labeled with mRFP-tagged ApsB. The right fluorescent pictures show mitotic and astral microtubules emanating from the SPBs (labeled with GFP-Spa10) and cytoplasmic microtubules emanating from a septal MTOC. (C) Schemes of a SPB and a sMTOC.