Figure 4.
Evidence that the nuclear envelope projections occur before changes in the nuclear envelope permeability barrier. An egg was injected with both a DiI-saturated oil drop to label the ER and with FDx to monitor nuclear envelope permeability. DiI-labeled, finger-like membrane projections protude into the nucleus before NEBD. DiI and 70-kDa FDx were imaged alternately, every 5 s. The DiI images were taken 5 s previous to the 70-kDa FDx image on the same row. The time in seconds from the beginning of the 70-kDa FDx sequence is indicated. The graph shows the average fluorescence intensity measured in a rectangle of 6.6 × 8.4 μm centered in the nuclear region. Letters on the graph indicate which panel of the figure corresponds to data points on the graph. The 70-kDa FDx begins to enter the nucleus in D, whereas the projections are present ∼2 min earlier in B. Bar, 10 μm.