Fig. 4. Activities of nuclear and septal MTOCs in wild type and apsB-mutant strains. (A) Scheme of MTOC activities. Cytoplasmic MTs (white arrows) emerge from different MTOCs (small white dots), e.g. the nuclear SPB (left) and MTOCs near the hyphal septa (right) (grey ball=nucleus; vertical black line=septum). (B) KipA is a MT plus-end marker and its fluorescence signal can be followed as comets (GFP-KipA) during MT growth (Konzack et al., 2005). The white arrow follows a GFP-KipA signal emerging at a septal MTOC (asterisk) (see supplementary material, Movies 11). Time is indicated in seconds. Bar, 3 µm. (C) Quantitative analysis of GFP-KipA counts at different MTOCs. Values are the average of 100-150 MTOCs. Wild-type strain: SSK92. Mutant strains: SDV24, SDV25.