Figure 2.

Indirect immunofluorescence microscopy of TGN38 variants expressed in Cos-7 cells. TGN38 constructs were stably expressed in Cos-7 African green monkey kidney fibroblasts and induced to comparable expression levels from the human metallothionein IIa promoter by the addition of empirically determined concentrations of cadmium chloride to the tissue culture medium. Cells expressing wild-type TGN38 (A and B), S331A (C and D), and S331D (E and F) were dual labeled with a mixture of monoclonal antibody against rat TGN38 (2F7.1) and polyclonal antibody recognizing the endogenous monkey orthologue of TGN38 (P12). Antibody to TGN38 was visualized by incubation with FITC-conjugated anti-mouse Ig as secondary antibody (panels A, C, and E). Antibody to the endogenous monkey orthologue was visualized by incubation with Texas Red-conjugated anti-rabbit Ig as secondary antibody (panels B, D, and F).