Localization of HA-Ppt1p in yeast cells during early log phase growth. (A) Yeast cells expressing wild-type Ppt1p (W303; a, b, c) or HA-Ppt1p (WHT4-1; d, e, f) were subjected to immunocytochemistry using modified ABC amplification. DAPI was used for nuclear staining. The exposure time for the HA-Ppt1p (green) signal was 5 sec. (B) A spindle pole body protein, Spc42p fused with EGFP (Spc42p-EGFP) was expressed in W303 cells, and localized by both direct green fluorescence of EGFP (j) and indirect red immunofluorescence (k) using the same method of amplification. The exposure times for the direct EGFP signal and the indirect immunofluorescence signal were 5 sec and 40 msec, respectively. Wild-type cells (W303) were used as negative controls for both experiments (a, b, c, and g, h, i). All samples were observed with 1000 × magnification.