The nucleolus during mammary epithelial differentiation and early mammary tumorigenesis. Proliferating 3D cultures of MCF-10.B2 cells at day 20 were stained with ANA-N antibody to detect nucleoli (green) and counterstained with DAPI to delineate nuclei (blue). Under these conditions, cells form acini. The stack shown is presented as a projected image in Fig 1A (Day 20 control)of Meaburn and Misteli, 2008 J Cell Biol 180:39-50. The z-series was recorded with a Zeiss LSM 510 META confocal microscope with a 63x 1.4 NA objective lens.