A sequence in the N-terminal region of human uracil-DNA glycosylase with homology to XPA interacts with the C-terminal part of the 34-kDa subunit of replication protein A

Academic Article


  • Uracil-DNA glycosylase releases free uracil from DNA and initiates base excision repair for removal of this potentially mutagenic DNA lesion. Using the yeast two-hybrid system, human uracil-DNA glycosylase encoded by the UNG gene (UNG) was found to interact with the C-terminal part of the 34-kDa subunit of replication protein A (RPA2). No interaction with RPA4 (a homolog of RPA2), RPA1, or RPA3 was observed. A sandwich enzyme-linked immunosorbent assay with trimeric RPA and the two-hybrid system both demonstrated that the interaction depends on a region in UNG localized between amino acids 28 and 79 in the open reading frame. In this part of UNG a 23-amino acid sequence has a significant homology to the RPA2-binding region of XPA, a protein involved in damage recognition in nucleotide excision repair. Trimeric RPA did not enhance the activity of UNG in vitro on single- or double-stranded DNA. A part of the N-terminal region of UNG corresponding in size to the complete presequence was efficiently removed by proteinase K, leaving the proteinase K-resistant compact catalytic domain intact and fully active. These results indicate that the N-terminal part constitutes a separate structural domain required for RPA binding and suggest a possible function for RPA in base excision repair.
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    Author List

  • Nagelhus TA; Haug T; Singh KK; Keshav KF; Skorpen F; Otterlei M; Bharati S; Lidmo T; Benichou S; Benarous R
  • Start Page

  • 6561
  • End Page

  • 6566
  • Volume

  • 272
  • Issue

  • 10