Fig. 2. Bir1p localizes to the cytoplasm and the nucleus of yeast cells. Confocal fluorescence micrographs (top), and coincident fluorescence and differential-interference contrast images (bottom) are shown. Haploid cells, whose endogenous Bir1p was C-terminally tagged with GFP and transformed with pYES-ProtA-Nma111p, were examined by direct fluorescence after induction of Nma111p overexpression (left panels). bir1 cells were transformed with pNOPPATA1W-Bir1p to express N-terminal protein-A-tagged Bir1p (ProtA-Bir1p) and examined by indirect immunofluorescence using a primary polyclonal anti-protein-A antibody and a secondary anti-rabbit IgG antibody labelled with Alexa Fluor 488 (middle panels). Haploid cells that were genomically tagged with a tandem-affinity purification tag at the C-terminus of endogenous Bir1p (Bir1p-TAP) and analysed by indirect immunofluorescence using a primary anti-protein A antibody and a secondary antibody labelled with Alexa Fluor 488 (right panels). Bars, 5 µm.