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. 2020 Jan 17;6(1):e03238. doi: 10.1016/j.heliyon.2020.e03238

Figure 1.

Figure 1

Centrosome positioning during cell division. (A) Time-lapse series of differential interference contrast (DIC)/fluorescence images showing a U2OS cell stably expressing TUBG-shRNA and co-expressing GFP-tagged sh-resistant γ-tubulin1 (γTubulinGFP). The image series presents chosen frames illustrating the changes in the position of the centrosome(s) during cell division. The outer membrane of the cell (yellow lines) and the nucleus (dotted lines) are indicated by solid and dotted lines, respectively. The model [19] depicts the changes known to occur in the centrosome(s) during cell division: the centrosome duplicates in S phase; the two centrosomes separate at the end of G2 phase; the disassembly of the nuclear envelope permits the repositioning of centrosomes to regulate the formation of the mitotic spindle in prophase; the chromosomes are aligned in the middle of the cell and microtubules emanating from the centrosomes are attached to the chromosomes in metaphase; the mitotic spindle pulls apart the chromatin between the newborn cells in telophase. A nuclear membrane is formed around each set of chromosomes, and the division of the cytoplasm between new born cells is ongoing (cytokinesis) for the final generation of two cells. The images shown were collected every 5 min. See also Movie 1. (B) Time-lapse fluorescence images of a U2OS cell stably expressing the following constructs: TUBG-shRNA, GFP-tagged sh-resistant γ-tubulin1 (γTubulinGFP), and mCherry-lamin B1. The images represent selected frames showing the changes in location that the centrosomes undergo during cytokinesis. Here, after furrow ingression, one of the centrosomes transiently moved to the growing furrow to allow the completion of cell division. Images were collected every 4 min. See also Movie 2. (A and B) Stable cell lines were obtained and time-lapse experiments were performed as previously described [20, 25, 68, 69]. In both A and B an arrow indicates a centrosome. Scale bars: 10 μm. This data is from unpublished works by Alvarado-Kristensson et al.