The following antibodies were used: Gapdh (ab9484, Abcam); PCNAmUb Lys 164 (13439, Cell Signaling Technology); PCNA (PC10, Sigma); XlRad18 (10 (link)); SMAUG (27 (link)); Tubulin (DM1A, T9026 for Drosopohila, Sigma); and Mlh1 (ab14206 Abcam). The PC10 antibody cross-reacts with D. melanogaster PCNA (28 (link)).