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. 2019 Dec 24;8:e52220. doi: 10.7554/eLife.52220

Figure 1. Loss of Gravin perturbs duration of mitosis and accumulation of active mitotic kinases at centrosomes.

(A) Representative time-lapse images of primary MEFs derived from wildtype (top) and Gravin knockout (bottom) cells. Cells transiently expressing GFP-H2B were monitored through mitosis. (B) Quantification of time-lapse experiments depicts duration of mitosis from nuclear envelope breakdown to the onset of anaphase; Wildtype, n = 199, Gravin KO, n = 121, ****p<0.0001. (C, D) Structured illumination microscopy (SIM) of representative mitotic HEK293 cells stably expressing Control or Gravin shRNA. Composite images (left) depict cells stained for α-tubulin (green) and DNA (blue). Immunofluorescence of pT210-Plk1 (C) and pT288-AurA (D) as an index of kinase activity (mid) and 5X magnification of centrosomal pT210-Plk1 (C) and pT288-AurA (D) signals (insets). (E, F) Quantification of centrosomal pT210-Plk1 (E) and pT288-AurA (F) immunofluorescence. Points represent individual cells (n). Data are normalized to Con shRNA; (E) Con shRNA, n = 45, Gra shRNA, n = 46, **p=0.0036; (F) Con shRNA, n = 62, Gra shRNA, n = 66, ****p<0.0001. Experiments were conducted at least three times (N = 3) and P values were calculated by unpaired two-tailed Student’s t-test. Data are mean ± s.e.m. (G) SIM micrographs of Gravin (top, gray and magenta) in interphase and pT766-Gravin (bottom, gray and magenta) in mitotic U2OS cells. Composite images (right) also depict α-tubulin (green) and DNA (blue). (H) Schematic of global drug distribution (gray) vs drug targeting to centrosomes (green). Gravin scaffolds centrosome-localized pools of Plk1 and AurA.

Figure 1.

Figure 1—figure supplement 1. Confirmation of Gravin loss in MEFs and detection of Gravin and pT766-Gravin in mitotic and interphase U2OS cells.

Figure 1—figure supplement 1.

(A) Immunoblot confirming Gravin expression (top) in wildtype (WT) but not Gravin knockout (KO) primary MEFs. GAPDH loading controls (bottom). (B) Matched controls pertaining to Figure 1G. SIM micrographs of Gravin (top, gray and magenta) in mitotic and pT766-Gravin (bottom, gray and magenta) in interphase U2OS cells. Composite images (right) also depict α-tubulin (green) and DNA (blue).
Figure 1—video 1. Loss of Gravin perturbs duration of mitosis.
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Time-lapse video of an average wildtype (top) and Gravin KO (bottom) MEF cell expressing GFP-H2B. The interval between each frame is 5 min. Scale bar represents 5 µm. Related to Figure 1A.