Activity of FEN1 endonuclease on nucleosome substrates is dependent upon DNA sequence but not flap orientation.

ABSTRACT: We demonstrated previously that human FEN1 endonuclease, an enzyme involved in excising single-stranded DNA flaps that arise during Okazaki fragment processing and base excision repair, cleaves model flap substrates assembled into nucleosomes. Here we explore the effect of flap orientation with respect to the surface of the histone octamer on nucleosome structure and FEN1 activity in vitro. We find that orienting the flap substrate toward the histone octamer does not significantly alter the rotational orientation of two different nucleosome positioning sequences on the surface of the histone octamer but does cause minor perturbation of nucleosome structure. Surprisingly, flaps oriented toward the nucleosome surface are accessible to FEN1 cleavage in nucleosomes containing the Xenopus 5S po

SUBMITTER: Jagannathan I 

PROVIDER: S-EPMC3093826 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature