Fig. 5. Visualization of the cell cycle as a function of GFP-histone expression. (A) Structure of the GFP-tagged histone H1 chimeric gene. (B,C) Confocal images of the nucleus were identified in interphase (B) and mitotic (C) cells by GFP-H1 fluorescence. (D-F) A series of time-lapse micrographs of GFP fluorescence images superimposed on phase contrast images. They show differing cytokinesis processes in three strains of GFP-H1-expressing cells grown on solid substrates: mhcA^- cells undergoing cytokinesis B (D); amiA^- cells failing to divide (E); and amiA^-/mhcA^- cells undergoing cytokinesis C (F). Bars, 10 µm.