Uracil DNA glycosylase activity on nucleosomal DNA depends on rotational orientation of targets.

ABSTRACT: The activity of uracil DNA glycosylases (UDGs), which recognize and excise uracil bases from DNA, has been well characterized on naked DNA substrates but less is known about activity in chromatin. We therefore prepared a set of model nucleosome substrates in which single thymidine residues were replaced with uracil at specific locations and a second set of nucleosomes in which uracils were randomly substituted for all thymidines. We found that UDG efficiently removes uracil from internal locations in the nucleosome where the DNA backbone is oriented away from the surface of the histone octamer, without significant disruption of histone-DNA interactions. However, uracils at sites oriented toward the histone octamer surface were excised at much slower rates, consistent with a mechanism requi

SUBMITTER: Cole HA 

PROVIDER: S-EPMC2807341 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature