Stabilization of the metaphase spindle by Cdc14 is required for recombinational DNA repair (2016)
Figure 3

Figure 3. Cdc14 is released from the nucleolus in response to DNA damage.

A) Live-cell imaging of Cdc14-YFP and Cnm67-RFP asynchronous cells treated with the DNA damage agent phleomycin. Cells were grown overnight and phleomycin was added to a final concentration of 1μM. Samples were taken at different intervals to determine Cdc14 localization. Cnm67 was used as SPB reporter to determine spindle length. Scale bar: 3μm. Graphs represent the average percentage ± SD from three independent experiments of cells arrested in metaphase (left graph) and with Cdc14 signal at the nucleoplasm (right graph). Western blot analysis to analyse Rad53 and Net1 phosphorylation levels under these conditions are shown. Note that Rad53 is rapidly phosphorylated in response to phleomycin and maintained throughout the entire experiment. Detection of Net1 phosphorylation levels was achieved by using Phos-tag polyacrylamide gels. Coomassie staining is showed as loading control.

B) Cell cycle profile of Cdc14 localization and Net1 phosphorylation in the absence of DNA damage. A strain containing Cdc14-GFP and Net1-HA was blocked in G1 by using the pheromone alpha-factor and released into the cell cycle. Samples were taken at different time-points to analyse Cdc14 spatial localization and Net1 phosphorylation levels. A representative picture of non-released (T0), partially released (T60) and fully released (T75) Cdc14 from the nucleolus is shown. Scale bar: 3μm. Graph represents the percentage ± SD from three independent experiments of cells with no released, partially released (FEAR) and totally released (MEN) Cdc14 from the nucleolus along the cell cycle. Western blot analysis showing Net1 phosphorylation through the cell cycle is included. The separation of the phospho-bands was achieved by using Phos-tag polyacrylamide gels as in Fig 3A. Coomassie staining is depicted as loading control.

C) Cells expressing Cdc14-YFP and Cnm67-RFP were grown overnight and blocked in G2/M by using nocodazole prior phleomycin treatment (1μM). Samples were taken every 30 minutes to follow Cdc14 re-localization. The efficiency of the arrest was determined as in Fig 3A. Scale bar: 3μm. Graphs represent the percentage ± SD of cells with Cdc14 nucleolar exclusion (left graph) and cells arrested in metaphase (right graph) from three independent experiments.

D) Live-cell imaging of Cdc14 localization in the presence of a non-reparable DSB at the MAT locus. Cells were grown overnight and the HO endonuclease was expressed by adding galactose to the media, thus producing a DSB on chromosome III. Cdc14, the SPB component Cnm67 and the DNA damage checkpoint protein Ddc2 (used as DSB reporter) were labelled with the green, red and cyan fluorescent proteins respectively. Micrographs display the maximum projection of 9 planes showing Cdc14 co-localizing with the DSB and the SPBs in response to DNA damage (arrows). Scale bar: 3μm. Graphs represent the percentage ± SD from three independents experiment of cells with nucleoplasmic Cdc14 along the HO endonuclease induction (left graph) and the percentage of Cdc14-SPB-DSB co-localization after 5h in galactose (right graph).

E) Western blot showing Net1-6HA phosphorylation state before and after the generation of a DSB induced by the HO expression. A strain lacking the HO endonuclease under the galactose promoter was used as undamaged control. The phospho-bands were resolved by using Phos-tag polyacrylamide gels as in Fig 3A and Fig 3B. Coomassie staining is depicted as loading control.

Data information: Raf, raffinose. Gal, galactose. FEAR, Fourteen-Early Anaphase Release. MEN, Mitotic Exit Network. Nz, Nocodazole. DSB, Double Strand Break. SPB, Spindle Pole Body.