Fig. 6. The centrosomal localization of BBS6 is abrogated by several mutations found in patients, and is conferred by the apical domain region. (A) Schematics of the BBS6 variants tested. The equatorial, intermediate and apical domain regions are indicated, along with the positions of the six missense variants, and the extent of the truncation in the delGG mutant. (B) Western blot analysis of all GFP-tagged BBS6 variants expressed in COS-7 cells, as detected with an anti-GFP antibody. (C) Localization of GFP-tagged BBS6 variants detected via GFP fluorescence. Two mutants (R156L and C499S) localize to the centrosome, as with GFP-tagged wild-type (WT) BBS6 (WT: 69% of the cells show centrosomal localization, n=190, R156L: 53%, n=130, C499S: 72%, n=130, top panels); four variants fail to localize to the centrosome (G52D: 2% of the cells show centrosomal localization, n=155, G345E: 1%, n=100, D285A: 7%, n=150 and T325P: 0%, n=128; bottom panels). (D) The GFP-tagged apical domain of BBS6 localizes to the centrosome, as does the delGG truncation mutant (apical: 46% of the cells show centrosomal localization, n=144, delGG: 34%, n=200).