Figure 4.
BrdU foci contain replication proteins and are associated with internal nuclear lamin A/C structures. (A) The localization of p150 (CAF-1; upper panels, green) and PCNA (lower panels, green) was determined during G1- and S-phase progression. At the G1-S boundary, both CAF-1 and PCNA foci increase in intensity. The mouse monoclonal antibody against p150 (MAB1) was kindly provided by B. Stillman. Similar results were seen with antibodies to the p60 subunit of CAF-1. PCNA was visualized with a rabbit polyclonal antibody (Santa Cruz). (B) Localization of BrdU was compared to that of p150 (red) in S-phase cells. DNaseI was used to expose BrdU. For this experiment, replication sites were detected using a rat anti-BrdU antibody (Harlan/Sera-Lab, green). (C) Early S-phase BrdU patterns were compared to that of UBF (upper panels, red), a nucleolar transcription factor, and nuclear lamins A/C (lower panels, red). The rabbit polyclonal anti-UBF antibody was kindly provided by L. Rothblum. Lamins A/C were visualized with a mouse monoclonal antibody (636, Santa Cruz). In all images, DNA is visualized by DAPI staining (blue).