Figure 4.

Depletion of RCC1 leads to defects in chromosome segregation. Embryos expressing GFP::β-tubulin and GFP::histone H2B from either control worms (A) or worms depleted of RCC1 (B) were observed by time-lapse microscopy. Still images are shown with indication of time (minutes:seconds) relative to anaphase onset. Anterior of the embryos is on the left. RCC1 depletion causes problems in the initial phase of spindle formation and in DNA segregation. Bar, 10 μm. (C) Comparison of one-cell embryos from GFP::RCC1 worms grown on either control bacteria (left), or bacteria expressing dsRNA corresponding to RCC1 (middle). RNAi against RCC1 decreases the level of fluorescence to that of N2 embryos with no GFP gene (right). Dotted white lines indicate pronuclei and plasma membranes. Bar, 10 μm. (D) Distance between the two centrosomes was measured relative to the total length of the embryo. Shown is the average of several wild-type (diamonds, n = 9), RCC1(RNAi) (squares, n = 10), and RanGAP(RNAi) (triangles, n = 5) embryos as a function of time. Each embryo was aligned relative to anaphase onset, which defines t₀. Vertical lines represent the SD at each time point. Also shown is a single Ran(RNAi) embryo (crosses). For wild-type embryos, approximate timing of pronuclear meeting and pronuclear envelope breakdown (NEBD) is indicated as is DNA segregation and spindle rocking.