FEN1 participates in repair of the 5'-phosphotyrosyl terminus of DNA single-strand breaks

In this study, we purified a flap endonuclease 1 (FEN1) and xeroderma pigmentosum group G protein (XPG) in the 5' to 3' structure-specific DNA endonuclease family and synthesized single-strand break DNA substrates containing a 5'-phoshotyrosyl bond, mimicking the Top2–SSB complex. We found that FEN1 and XPG did not remove the 5'-phoshotyrosyl bond-containing DSB substrates but removed the 5'-phoshotyrosyl bond-containing SSB substrates. Under DNA repair conditions, FEN1 efficiently repaired the 5'-phoshotyrosyl bond-containing SSB substrates in the presence of DNA ligase and DNA polymerase. Therefore, FEN1 may play an important role in the repair of Top2–SSB complexes in etoposide-treated cells.

Source: Carcinogenesis - January 5, 2016 Category: Cancer & Oncology Authors: Kametani, Y., Takahata, C., Narita, T., Tanaka, K., Iwai, S., Kuraoka, I. Tags: Original Manuscript Source Type: research