Fig. 2. Cbs cycles from the cytoplasm to DNA during mitosis. Mitotic series (PDI::GFP stock) immunostained for GFP to mark the ER lumen (green), Cbs (red), and stained for either Cnn, microtubles or DNA TOTO-3 (blue) during mitosis in syncytial embryos. From early prophase (A-D) to late prophase (E-H), Cbs rapidly changes from a diffuse cytoplasmic haze, to small particles that accumulate near centrosomes and begin to migrate into the nucleus. During prometaphase Cbs is present in elongating spindles and at chromatin (I-L), but is present only at chromatin by late metaphase (M-P). The ER forms an envelope around the spindle during these stages, but is absent from the spindle proper. Throughout anaphase (Q-T) Cbs remains associated with DNA, although, as the ER begins to disperse, small cytoplasmic Cbs particles are present. At late telophase (U-X) Cbs moves towards centrosomes and astral microtubules, and rapidly fragments into small particles that disperse into the cytoplasm. The ER is present throughout the cytoplasm and at the spindle mid-bodies during telophase, but does not colocalize with Cbs. Bar, 20 µM.