FIGURE 8.

Immunolocalization of different subunits of the 20S proteasome. Lens cryosections were probed with monoclonal antibodies to the XAPC7 subunit (subunit α4) (A) and polyclonal antibodies to the “core” (B). Merged images (C, D) of lens epithelial layer show that these subunits colocalized in the cytoplasm and nucleus. In fiber cells, the 20S subunit XAPC7 localized exclusively to the nuclei (E). Double staining of nuclei with 20S core (F) and lamin B (G) antibodies shows that the proteasome remained in the nuclei when the nuclear membrane started to be dismantled. Scale bars: (C, E)50 μm; (D) 10 μm; (F, G) 20 μm.