Figure 2.

Nucleotide insertion at the lesion site by Pol IV restarts leading-strand synthesis across the blocking lesion. (A) Replication products were digested with MscI and AseI, yielding ³²P-labeled products with the size of 86 mer for the leading strand and 90 mer for the lagging strand. If Pol III stops one-nucleotide before the BP(−) lesion, leading products would be 40 mer. (B) Digested replication products were subjected to sequencing gel analysis. The ³²P-labeled products of pMOL7-BP(−) (lanes 5, 7, 9 and 11) or pMOL7-control (lanes 6, 8, 10 and 12) in the absence (lanes 5, 6, 11 and 12) or presence of Pol IV (wild-type in lanes 7 and 8, D8A-mutant in lanes 9 and 10) are shown. 5′-³²P-labeled ladder markers are indicated in lanes 1–4.