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. 2018 Nov 28;13(11):e0208022. doi: 10.1371/journal.pone.0208022

Fig 5. Cyclin B dynamics in un-, colchicine-, and mAb 6H11-injected embryos.

Fig 5

(A) Confocal image sequence of the relative dynamics of Cyclin-B-GFP (in green) and H2Av-RFP (in red) during a mitotic cycle in an untreated embryo. Arrowheads point to enhanced Cyclin-B-GFP localization at the nuclear rim at the time of NEB. Time is indicated in minutes and seconds. (B) Diagram of the dynamics of Cyclin B (in green) localization during mitosis in unperturbed embryos. (C) Confocal image sequence of Cyclin-B-GFP (in green) and H2Av-RFP (in red) dynamics during a mitotic cycle in a colchicine-injected embryo. Arrowheads indicate Cyclin B localization to the nuclear rim and kinetochores similar to that observed in untreated embryos. (D) Confocal image sequence of a Cyclin-B-GFP (in green) and H2Av-RFP (in red) expressing embryo injected with Chromator mAb 6H11. The antibody was injected at interphase and the image sequence starts approximately 2 min after the first cell cycle was completed. Although Cyclin-B-GFP levels appear to be continuously increasing within the nucleus there is no indication of its normal enrichment at the nuclear rim, kinetochores of the condensed chromosomes, or centrosomes. (E) Comparison of Cyclin B dynamics in colchicine- and mAb 6H11-arrested embryos. In wild-type Cyclin B is present at low levels in the nuclear interior, accumulates within the spindle matrix at prometaphase and transiently relocates to the nuclear rim, the kinetochores, and the centrosomes. In colchicine-arrested embryos Cyclin B dynamics are as in wild-type embryos; however, in mAb 6H11-arrested embryos Cyclin B-levels increase within the nucleus without localization to the nuclear rim, kinetochores, or centrosomes. The asterisk indicates the transient Cyclin B localization to the nuclear rim just prior to NEB in colchicine-treated embryos. (F) Plot of average pixel density within the nucleus as a function of time for Cyclin B-GFP. Average pixel density for an area outside the nuclei was subtracted at each time point. Increased levels of Cyclin B-GFP accumulate in the nucleus as chromosome condensation commences (arrow).