Nucleolar localization of SBDS is abrogated by actinomycin D treatment. HeLa cells were treated with 2 nM actinomycin D for the times indicated. Cells were fixed and stained for SBDS (green) and counterstained with DAPI (blue) to visualize nuclei (63× magnification). See “Patients, materials, and methods; Immunofluoresence” for image acquisition details.