Fig. 5 MT breakage. Distal end of a MT (red) in a PtK1 cell shows dynamic instability,--it grows, shortens and starts growing again (0-148); breakage (150) produces a nascent plus end of the remaining long MT segment (red) which shortens (153-285), and a nascent minus end of a newly formed free MT (yellow) which remains stable (153-285). The plus end of the free MT grows. Time shown in upper right corner of each frame in seconds. Scale bar, 5 µm.