Figure 2.

Removal of ER remnants associated with the outer nuclear envelope by addition of 0.5% Triton X-100 in the extraction buffer. A, ER of cv Xanthi cells stained with ER-Tracker Blue-White DPX. B, The ER-associated chaperone BiP is detected in an unfractionated protein extract but not in a nuclear protein extract: lane 1, 30 μg of nuclear protein; lanes 2 and 3, 50 and 30 μg of unfractionated protein, respectively. C and D, cv Xanthi nuclei extracted in the presence of Triton X-100 (D) are not stained for ER in comparison with nuclei extracted without Triton X-100 (C). Bars = 10 μm.