Fig. 1. Identification of a condensin complex in Drosophila and characterisation of CAP-D2 during interphase. (A) Identification of a condensin complex in 0- to 5-hour embryo extracts following immunoprecipitation with an antibody recognizing Drosophila CAP-D2. Three 0.5 M NaCl washes and three 2% SDS elutions are shown for preimmune and immune precipitations. The samples were analysed by immunoblotting with SMC2, SMC4, CAP-D2 and CAP-H/Barren antibodies. A fraction of SMC2 and SMC4 eluted in the washes, but most was eluted with 2% SDS, while CAP-D2 and CAP-H/Barren only eluted with 2% SDS. (B-D) S2 cultured cells were cytospun onto poly-L-lysine slides, then fixed and stained with various antibodies as described. (B) CAP-D2 localises in the nucleus during interphase. G1 cells (using -tubulin as a marker) show nuclear staining for CAP-D2 with a diffuse cytoplasmic staining. Cells in G1 phase (single centrosome, arrow in upper panel) have less nuclear CAP-D2 than cells with two centrosomes (cells in S or G2 phase, arrow in lower panel). -tubulin (red), CAP-D2 (green) and DNA (blue). (C) S phase cells (detected after BrdU incorporation) show strong nuclear staining for CAP-D2, but at differing levels. BrdU (green), CAP-D2 (red), and DNA (blue). (D) Cells in late G2/early prophase (arrow) show an intense staining for CAP-D2. Cyclin B (nuclear during late G2/early prophase) was used as a marker for this stage. Cyclin B (green), CAP-D2 (red) and DNA (blue).