Figure 6
From: Centrosome proteins form an insoluble perinuclear matrix during muscle cell differentiation
The perinuclear matrix of centrosome proteins disassembles in mitotic egg extract. Purified nuclei from differentiated C2C12 cells were incubated in Xenopus egg extract and driven through the cell cycle in vitro. (A) Nuclei in extract in S-phase. Left: PCM-1; right: DNA. Continued incubation of nuclei in extract entering prometaphase (B), and metaphase (C). Condensation of chromosomes (right) and disintegration of the perinuclear matrix of PCM-1 (left) are visible. (D) Incubation of Xenopus sperm in parallel extract reactions produced mitotic spindles. Left: Rhodamine-labelled tubulin; right: DNA. (E – H) Nuclei from differentiated C2C12 cells were incubated in Xenopus egg extract as in (B). Samples in S-phase and prometaphase were processed for immunofluorescence of PCM-1, pericentrin, gamma-tubulin, and nesprin 1, as indicated. Deconvolved sections are shown. Left column: S-phase; second and third column: prometaphase; right column: merged signals of second and third columns. Bars, (D) 10 μm, (H) 5 μm.