Flap endonuclease 1 efficiently cleaves base excision repair and DNA replication intermediates assembled into nucleosomes.
Flap Endonuclease 1 (FEN1) plays important roles both in DNA replication and in base excision repair (BER). However, in both processes FEN1 substrates are likely to be assembled into chromatin. In order to examine how FEN1 is able to work within chromatin, we prepared model nucleosome substrates containing FEN1-cleavable DNA flaps. We find that human FEN1 binds and cleaves such substrates with efficiencies similar to that displayed with naked DNA. Moreover, we demonstrate that both FEN1 and human DNA ligase I can operate successively on DNA within the same nucleosome. These results suggest that some BER steps may not require nucleosome remodeling in vivo and that FEN 1 activity during Okazaki fragment processing can occur on nucleosomal substrates.
Huggins
Christine F
CF
Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY 14642, USA.
Chafin
David R
DR
Aoyagi
Sayura
S
Henricksen
Leigh A
LA
Bambara
Robert A
RA
Hayes
Jeffrey J
JJ
D000818:Animals; D020137:Base Pair Mismatch; D001483:Base Sequence; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000378:metabolism; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D004706:Endodeoxyribonucleases / Q000378:metabolism / Q000502:physiology*; D045585:Flap Endonucleases; D006801:Humans; D017665:Hydroxyl Radical; D007700:Kinetics; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D013997:Time Factors; D014981:Xenopus
D002843:Chromatin; C000607892:LIG1 protein, human; D009707:Nucleosomes; D017665:Hydroxyl Radical; D004247:DNA; D004706:Endodeoxyribonucleases; D045585:Flap Endonucleases; C468317:FEN1 protein, human; D011088:DNA Ligases; D000072481:DNA Ligase ATP