SBDS nucleolar localization is cell-cycle dependent. (A) HeLa cells were synchronized with a double thymidine block, then released for the times indicated. Cells were fixed and stained for SBDS. An aliquot of cells was also fixed for flow cytometry (right). Cells in late telophase are indicated with arrows. (B) SBDS protein levels remain constant throughout the cell cycle. HeLa cells synchronized with a double thymidine block were released for the indicated times. Cell lysates were immunoblotted for Fanconi anemia, complementation group D2 (FANCD2), SBDS, and tubulin.