Premium
DNA base excision repair of uracil residues in reconstituted nucleosome core particles
Author(s) -
Nilsen Hilde,
Lindahl Tomas,
Verreault Alain
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf581
Subject(s) - dna glycosylase , base excision repair , biology , nucleosome , ap site , dna repair , microbiology and biotechnology , nucleotide excision repair , uracil dna glycosylase , dna ligase , dna polymerase , ap endonuclease , base pair , dna , biochemistry , histone
The human base excision repair machinery must locate and repair DNA base damage present in chromatin, of which the nucleosome core particle is the basic repeating unit. Here, we have utilized fragments of the Lytechinus variegatus 5S rRNA gene containing site‐specific U:A base pairs to investigate the base excision repair pathway in reconstituted nucleosome core particles in vitro . The human uracil‐DNA glycosylases, UNG2 and SMUG1, were able to remove uracil from nucleosomes. Efficiency of uracil excision from nucleosomes was reduced 3‐ to 9‐fold when compared with naked DNA, and was essentially uniform along the length of the DNA substrate irrespective of rotational position on the core particle. Furthermore, we demonstrate that the excision repair pathway of an abasic site can be reconstituted on core particles using the known repair enzymes, AP‐endonuclease 1, DNA polymerase β and DNA ligase III. Thus, base excision repair can proceed in nucleosome core particles in vitro , but the repair efficiency is limited by the reduced activity of the uracil‐DNA glycosylases and DNA polymerase β on nucleosome cores.