Fig. 1. Subcellular distribution of various domains of clusterin. (A) Schematic representation of the different GFP chimeras between GFP and various domains of rat clusterin: full-length clusterin deleted from secretory signal peptide (SP-clu, amino acids 22-447), -subunit (-clu, amino acids 22-226), ß-subunit (ß-clu, amino acids 227-447). (B) COS-7 cells were observed in fluorescence microscopy 36 hours after transfection with the different expressing vectors. Cells transfected with GFP--clu were counterstained with DAPI in order to visualize the nucleus. Protein expression patterns shown are representative of patterns observed in the majority of transfected cells obtained from several experiments. Bar, 10 µm. (C) Juxtanuclear aggregation was also detected by clusterin immunostaining when SP-clu and -clu domains are expressed without GFP fusion. Cells were counterstained with DAPI. Bar, 10 µm. (D) Morphology of clusterin immunostained aggregates in tissue sections of aged rat brain closely resembles those observed in COS-7 cells overexpressing GFP--clu (right). Bar, 10 µm. Reproduced with permission from Blackwell Publishers/Blackwell Science Ltd/Polity Press (Senut et al., 1992).