Continuing coverage: Researchers at UTMB have done in vitro experiments that have brought to light that NEIL1 rides in front of the replication complex looking for single-strand DNA damage. According to Muralidhar Hegde, lead author on the paper, “As soon as it encounters the base damage, NEIL1 binds to the damage site and flags it, and replication cannot continue. The replication machinery stalls and then regresses, and the two strands come back together which allows repair of the damaged base in duplex DNA, replacing the damaged base with the appropriate normal base.” Once that takes place, the DNA zipper begins opening again. The news also appears in Science Daily.