FIG. 2.

The UDS assay measures repair ability. (A) DNA repair in fibroblasts. Normal (CCD27Sk), XPE (XP2RO), and XPC (GOR DO) fibroblasts were plated in 60-mm-diameter dishes and subjected to the UDS protocol as described in Materials and Methods. Repair seen in the normal cells was set to 100%, and repair for the XPC and XPE cells was compared to this value (numbers above the bars). (B) XAP-1/UVDDB is not detected in XP2RO cells. HeLa cells and XP fibroblasts were extracted and immunoprecipitated with either preimmune rabbit antiserum or antiserum produced against a carboxy-terminal peptide of XAP-1/UVDDB (37). Following fractionation by sodium dodecyl sulfate–8% polyacrylamide gel electrophoresis and Western transfer, the proteins were detected with antiserum produced against an amino-terminal peptide of XAP-1/UVDDB (37) and enhanced chemiluminescence (Amersham, Arlington Heights, Ill.). The 127-kDa protein (arrowhead at right) was detected in HeLa cells (lane 2), XPC cells (lane 3), and normal fibroblasts (data not shown) but not in XPE fibroblasts (lane 4) or HeLa cells immunoprecipitated with preimmune rabbit serum (lane 1). The original autoradiogram was photographed with the U.V.P. documentation system (SW2000; U.V.P. Inc., San Gabriel, Calif.).