Fig. 3. Subcellular localization of endogenous SLMAP in NIH 3T3 cells. (A) Immunofluorescent labeling of SLMAP proteins using anti-SLMAP(C) antiserum revealed staining of reticular formations, the cytosol and perinuclear sites in paraformaldehyde fixed NIH 3T3 cells (a). Reduced cytosolic SLMAP staining and labeling of distinct foci at the perinuclear region was observed in detergent-extracted, paraformaldehyde-fixed cells (b). No immunoreactivity was observed with prior incubation of SLMAP(C) antisera with purified SLMAP protein (e) or in cells incubated with the pre-immune rabbit serum (f). Perinuclear foci staining was also evident in detergent extracted COS-7 cells stained with anti-SLMAP(N) (c). This staining pattern was not observed in COS-7 cells stained with the pre-immune serum (d). (B) SLMAP colocalizes with -tubulin at centrosomes throughout the cell cycle. Paraformaldehyde-fixed NIH 3T3 cells were co-stained with anti-SLMAP (a-e), anti--tubulin (f-j) and DAP1 (k-o). Representative cells in interphase (a,f,k), prophase (b,g,l), metaphase (c,h,m), anaphase (d,i,n) and telophase (e,j,o) are shown. Bars, 20 µm.