Understanding DNA Repair in Hyperthermophilic Archaea: Persistent Gaps and Other Reasons to Focus on the Fork

Figure 1

Possible fates of a replicative polymerase stalled at template dU. (a) Archaeal polymerases stall with the nascent 3′ end 4 nt ahead of the template dU [23]. (b) If the replication fork responds with immediate fork reversal, the dU is restored to its original context, and BER is required for resumption of fork progress. (c) If tight coupling is not preserved, the Mcm helicase and nonstalled polymerase (not drawn) would continue, creating ssDNA region on the stalled template vulnerable to structure- or single-strand-specific nucleases. Arrowheads on DNA strands represent 3′ ends.