Figure 1. Down-regulation of hRad18 leads to compromised FANCD2 monoubiquitionation and focus formation in response to DNA damage.
Populations of U2OS cells either transfected with hRad18 RNAi oligos or non-specific control oligos. 18 hours posttransfection, cells were split, and followed by 25J/m2 UV treatment. In a population of hRad18 downregulated cells, the ratio of monoubiquitinated FANCD2 over unmonoubiquitinated FANCD2 was decreased upon UV treatment at both time points examined (A). FANCD2 focus formation was also decreased in hRad18-silenced cells, and images shown in (B) were taken from these cells at time point of 4 hours [FANCD2 is a nuclear protein and forms foci (marked with yellow arrows) when monoubiquitinated] [(similar results were found in Hela cells (not shown)].