Fig. 2. Activation of new growth zones in G1- and S phase-arrested cells. (A) Images of cdc10-129 cdc11-119 cells at 36.5°C, after treatment with 50 µg/ml MBC for 3 hours: Nomarski (top) and DAPI stained (bottom). (B) Scoring of branching cdc10-129 and cdc10-129 cdc11-119 cells. Both cdc10-129 and cdc10-129 cdc11-119 cells were blocked for 3 hours before MBC treatment. Black arrow indicates drug addition. (C) Scoring of branching cdc25-22 cells. Cells were blocked for 3 hours at the restrictive temperature to block cells in G2 prior to mitosis. After 3 hours cells were released to the permissive temperature (25°C) to allow mitosis in the presence of 12 mM HU to prevent S phase to proceed. After 1.5 hours DMSO/MBC was added to the media. The effect of temperature and HU treatment was controlled using a wild-type strain. Both treatments had no effect on wild-type cells (data not shown). (D) Scoring of monopolar and bipolar cells in cdc25-22 cells blocked at 36.5°C and then released to 25°C in 12 mM HU. Bars, 5 µm.