FAC protein colocalizes with a nuclear protein marker in double-immunostained cells. Human 293 cells transfected with a FAC-encoding plasmid were analyzed by confocal laser-scanning microscopy after double labeling with affinity-purified anti-FAC1 and anti-p300 (a nuclear marker). The images shown contain a transfected cell population that express varying amounts of FAC protein. Nine optical sections taken from the apical (top left) to basal (bottom right) cell surface are shown. Composite images were created by merging corresponding images. The FAC protein is red, the p300 protein is green, and colocalization is yellow. (B) Optical section though a FAC-expressing cell (293/FAC) and 293 cells transfected with the parental pcDNA3 plasmid without the FAC gene insert (293/pcDNA3). (C) 293/pcDNA3 and 293/FAC cell lysates were analyzed by SDS-PAGE, transferred to nitrocellulose, and probed with the affinity-purified antibody used in the confocal analysis. Arrow indicates FAC protein. Molecular size markers are indicated at left.