Figure 2.

Immunolocalization of Spp1 in asynchronous cells. (A) Localization of Spp1-GFP (α-GFP), tubulin (α-Tat1p), and DAPI-stained nuclei (DAPI) in an exponential population of Spp1-GFP–expressing cells. Cells at different stages of interphase and mitosis are shown. (B) The expression of Spp1 protein is not cell cycle regulated. Total protein was prepared from cell samples at 25-min intervals after release from a cdc25-22 block, as described in MATERIALS AND METHODS, and probed with anti-Spp1 polyclonal antisera (top), or anti-Tubulin (bottom) as a loading control. The septation index is given as an estimate for cell synchrony and approximate time of S phase.