Figure 4

FZY antibodies prevent in vitro assembled spindles from exit of metaphase arrest in response to CaMKII. A suspension (20 l) of in vitro assembled spindles, arrested at metaphase by CSF, was treated for 15 min with affinity-purified FZY antibodies (Ab Fizzy) or the same amount (2 g) of rabbit immunoglobulins (CT: control). Constitutively active, in vitro translated CaMKII (CaMK) was added (2 l). Samples were taken before, or 45 and 90 min after CaMKII addition, and examined by fluorescence microscopy. Chromosomes were visualized by the fluorescence of the DNA-binding dye Hoechst 33342, and microtubules with rhodamine-labelled tubulin. The bar in the lower right micrograph corresponds to 2.5 m (same magnification for all micrographs).