Imaging of mitotic cell division and apoptotic intra-nuclear processes in multicolor.

To follow the cell division cycle in the living state, certain biological activity or morphological changes must be monitored keeping the cells intact. Mitotic events from prophase to telophase are well defined by morphology or movement of chromatin, nuclear envelope, centrosomes, and/or spindles. To paint or simultaneously visualize these mitotic subcellular structures, we have been using ECFP-histone H3 for chromatin and chromosomes, EGFP-Aurora-A for centrosomes and kinetochore spindles and DsRed-fused truncated peptide of importin alpha for the outer surface of nuclear envelope as living cell markers. Time-lapse images from prophase through to early G1 phase can be obtained by constructing a triple-fluorescent cell line (Sugimoto et al., Cell Struct. Funct. 27, 457-467, 2002). Here, we describe the multicolor imaging of mitosis of a human breast cancer cell line, MDA435, and a further application to characterizing the apoptotic chromatin condensation process in isolated nuclei by simultaneously visualizing kinetochores with EGFP and chromatin with a fluorescent dye, SYTO 59.