The fixed cells were then permeabilized with 0.05 % Triton X-100 in PBS and stained with FITC-conjugated rabbit anti-RPS3 antibodies (Primm Biotech), or AlexaFluor 594-conjugated rat anti-Flag antibodies (BD) for 40 min together with 1 μg/ml of Hoechst 33342 (Sigma) for 5 min at 25 °C.