Figure 2.

Detection of preincision complexes 1 and 2 by electrophoretic mobility shift assay. (A) Weak PIC1 forms with RFI-IV (XPA, RPA, TFIIH, and XPC) (lane 2), which is stabilized by XPG to form PIC2 (lane 3). No PIC2 can be detected with unmodified DNA (lane 5). (B) Formation of PIC2 requires all five repair factors. (C) PIC2 formation is ATP-dependent. Reaction mixtures were incubated in the presence or absence of ATP and separated on a 3.5% nondenaturing polyacrylamide gel as indicated. Open arrow shows the binding by a minor contaminant in the TFIIH factor.