Co-localization of BRCA1 antibody (K- 18) and nucleolin (7G2) in HCC1937 cells. A. rabbit polyclonal BRCA1 antibody stains many cell nuclei (green). The varied nuclear patterns include dot-like speckles, and intra-nuclear granules. B. Mouse monoclonal antibody to nucleolin stains nucleoli and many dot-like speckles (red). C. Some nuclear speckles, nucleoli, and portions of nucleoli stain for BRCA1(green) and nucleolin (red) to show co-localization (yellow). The arrow points to a nucleolus, in which there are BRCA1 (green), nucleolin (red), and merged (yellow) regions, which are distinct. D. Nomarski image of the same field as A,B,C. Bar = 20 μm.