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. 2017 Jun 12;36(14):2047–2060. doi: 10.15252/embj.201796664

Figure 4. A model nascent leading strand also inhibits XE activity on a fork structure containing a single triazole interstrand crosslink (ICL), but the presence of RPA overcomes this inhibition.

Figure 4

  1. Sequence and schematic structure of a “simple fork” containing a single triazole ICL at the fork junction and its predicted XE nuclease incision products when radiolabelled on the 5′‐end, based on the data obtained on non‐crosslinked fork structure in Figs 1, 2, 3, 4. Green circles denote 5′[32P]‐radiolabelled nucleotides.
  2. (Top panel) Nuclease activity of XE on 3′[32P]‐labelled crosslinked simple fork substrate. (Bottom panel) A schematic representation of the nuclease reaction and the incision products.
  3. (Top panel) Nuclease activity of XE on 5′[32P]‐labelled model native (lanes 2 and 3) and crosslinked (lanes 4 and 5) DNA substrates. The XE incision closest to the fork junction (2 nt from the junction, 26‐mer product) is inhibited in the presence of a crosslink at the fork junction (lane 5). (Bottom panel) Schematic representation of the nuclease reaction and its incision products.
  4. Nuclease activity of XE on 3′[32P]‐radiolabelled crosslinked substrate (simple fork; +leading strand) in the presence or absence of 80 nM RPA. XPF‐ERCC1 incisions reduced by a leading strand are overcome by the presence of RPA (compare lane 5 to lane 6).