XPG stimulates a 5' incision in C-(CTG)
HPR. (A) and (B) Analysis of HPR intermediates. HPR assays were performed using HeLa (HL) or AG08802 (AG) extracts under the condition of no DNA synthesis in the presence or absence of 0.3 μg of the purified recombinant XPG protein. The resulting DNA products were digested with BglI and BsmBI, followed by Southern blot analysis using an oligonucleotide probe specifically annealing to the nicked strand either near the BglI site (i.e., blue bar in A) or near the BsmBI site (i.e., red bar in B). (C and D) Time course analysis of incision intermediates of substrate C-(CTG)25 processed in HeLa extracts using the blue (C) or red (D) probe.