XB-IMG-136326
Xenbase Image ID: 136326
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FIGURE 1:. Cells commit to forward mitotic progression in prometaphase. (A) Chemical Cdk inhibition in mitosis induces cyclin B1 and securin degradation that requires APC/C-Cdc20. HeLa cells were transfected with 50 nM Cdc20 siRNA for 24 h or with 50 nM Cdh1 siRNA for 48 h. Mitotic cells were collected in nocodazole, treated with 10 μM Flavopiridol for 30, 60, and 90 min, then lysed and processed for Western blotting. Depletion of Cdc20, but not Cdh1, inhibits degradation of cyclin B and securin. (B) Summary of the live imaging data from Xenopus S3 cells treated with Cdk inhibitor, Flavopiridol, and Wee1/Myt1 inhibitor, PD 0166285 at different stages of the mitotic progression. Flavopiridol was washed out 1 h after addition. (C) A prophase Xenopus S3 cell expressing alpha tubulin-GFP was treated with Cdk inhibitor, Flavopiridol, and Wee1/Myt1 inhibitor, PD 0166285. After treatment with Cdk inhibitor, mitotic progression stopped, the chromosomes decondensed, and the cell returned to an interphase morphology. Flavopiridol was washed out at 1 h, and the cell re-entered mitosis, indicating that Cdk1-activating cyclins were preserved. The cell then progressed normally trough mitosis. (D) An early prometaphase Xenopus S3 cell expressing alpha tubulin-GFP was treated with Flavopiridol and PD 0166285. After treatment at time 0, the cell underwent cytokinesis without chromosome segregation, the chromosomes decondensed, the nuclear envelope reformed, and an interphase array of microtubules appeared. Flavopiridol was washed out at 1 h. However, the cell did not re-enter mitosis, indicating that it had advanced to a G1-like state. The complete time-lapse sequences for (A) and (B) are shown in Supplemental Videos 1 and 2. Bar, 10 μm. Image published in: Potapova TA et al. (2011) © 2011 Potapova et al. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |