Isolation of an allele-specific high-copy suppressor of rad18-74. (A) Partial restriction map of a rad18-74-suppressing plasmid. All isolates contained the open reading frames 19G10.6 and 19G10.7 (indicated as solid bars; introns in 19G10.7 [brc1] are indicated as hatched bars). P, PmeI; H, HindIII. Rescue of rad18-74 was assessed by UV-C irradiation survival curves. (B) rad18-74 and rad18-X were transformed with vector alone (□), C19G10.7 (brc1) (▵), or rad18 (●). Transformants were grown in selective media, and UV-C survival curves were determined as a percent survival compared with unirradiated controls.