Figure 4.

The recovery of replication following UV irradiation requires both the nucleotide excision repair genes and the recA and recF genes. The amount of replication occurring within 1 h postirradiation was analyzed by alkaline CsCl density gradients. Cells prelabeled with [¹⁴C]thymine were either UV-irradiated or mock-treated. Cells were then filtered and grown in media containing [³H]BrdUrd for 1 h to density label the replication occurring during this period. [Adapted with permission from ref. 21 (Copyright 1997, PNAS) and ref. 45 (Copyright 1999, Am Soc. Microbiol.).] Whereas little replication occurs in irradiated recA, recF, or uvrA mutants, wild-type cells and recBC mutants recover replication within this time period.