Figure 4.
Emerin-deficient cells have apparently normal nuclear mechanics. (a) Emerin-deficient primary mouse embryo fibroblasts have normalized nuclear strain comparable to wild-type cells when subjected to biaxial strain. In contrast, A-type lamin-deficient cells have significantly increased normalized nuclear strain (normalized nuclear strain = 0.27 ± 0.044, 0.23 ± 0.066, and 0.57 ± 0.059 for wild-type, emerin-deficient, and A-type lamin-deficient cells respectively; P < 0.001 for A-type lamin-deficient vs. wild-type cells). (b) Wild-type (left) and emerin-deficient (center) nuclei remain intact when microinjected with fluorescently labeled dextran, whereas A-type lamin-deficient nuclei (right) have more fragile nuclei that allow dextran to leak into the cytoplasm. Bars, 20 μm. (c) Emerin-deficient and wild-type cells have comparable frequency of nuclear rupture for nuclear microinjection at 500 hPa, whereas A-type lamin-deficient cells have a significantly increased fraction of ruptured nuclei (percentage of ruptured nuclei = 69 ± 4.9%, 64 ± 5.5%, and 96 ± 1.9% for wild-type, emerin-deficient, and A-type lamin-deficient cells, respectively).