Papers In Press, published online ahead of print February 28, 2006
J. Biol. Chem, 10.1074/jbc.M512959200
Submitted on December 5, 2005
Revised on February 22, 2006
Accepted on February 28, 2006
Drosophila DNA polymerase
interacts with recombination repair protein 1, the Drosophila homologue of human AP endonuclease 1
Ryo Takeuchi, Tatsushi Ruike, Ryo-ichi Nakamura, Kaori Shimanouchi, Yoshihiro Kanai, Yoko Abe, Ayumi Ihara, and Kengo Sakaguchi
Applied Biological Science, Tokyo University of Science, Noda-shi, Chiba-ken 1278-8510
Corresponding Author: j6404707{at}ed.noda.tus.ac.jp
Abasic (AP) sites are a threat to cellular viability and genomic integrity as they impede transcription and DNA replication. In mammalian cells, DNA polymerase (pol) ß plays an important role in the repair of AP sites. However, it is known that many organisms, including Drosophila melanogaster, do not have a pol ß homologue and it is unclear how they repair AP sites. Here, we screened for DNA polymerases that interact with the Drosophila AP endonuclease 1 homologue, Recombination Repair Protein 1 (Rrp1), and found that Drosophila pol (Dmpol ), DmREV3 and DmREV7, bound to Rrp1 in a protein-affinity column. Rrp1 directly interacted with DmREV7 in vitro and in vivo, but not with DmREV3. These findings suggest that the DNA polymerase partner for Rrp1 is Dmpol and that this interaction occurs through DmREV7. Interestingly, DmREV7 bound to the N-terminal region of Rrp1, which has no known protein homologue, suggesting that this binding is a species-specific event. Moreover, DmREV7 could stimulate the AP endonuclease activity of Rrp1, but not the 3-exonuclease activity, and form a homomultimer. DmREV3 could not incorporate nucleotides at the 5-incised tetrahydrofran sites, but did show strand displacement activity for one-nucleotide-gapped DNA, which was not influenced by either DmREV7 or Rrp1. Methyl methanesulfonate and hydrogen peroxide treatments increased mRNA levels of DmREV3 and DmREV7. On the basis of the direct interaction between DmREV7 and Rrp1, we suggest that Dmpol may be involved in the repair pathway of AP sites in DNA.