FAC localization does not change during the cell cycle. (A) HeLa cells were synchronized at G1 /S by double thymidine block and released into growth media. Cell synchrony was analyzed by FACS, as described in Materials and Methods. The percentage of cells in each phase of the cell cycle was determined by analyzing FACS data with the computer program CELLFIT (Becton Dickinson).
(B) Cells were metabolically labeled with 35S-methionine during the 2-hour intervals indicated. Proteins from whole cells (T), nuclear (N) extracts, or cytoplasmic (C) extracts were immunoprecipitated with anti-FAC antibody. Alternatively, protein from whole cells was immunoprecipitated with a preimmune serum (P). Immune complexes were resolved by SDS-PAGE. Molecular weight markers are in kilodaltons.
