title: Physical and functional interactions between nucleosomes and Rad27, a critical component of DNA processing during DNA metabolism.
abstract: Highly conserved eukaryotic histones are polybasic proteins that package DNA into nucleosomes, a building block of chromatin, allowing extremely long DNA molecules to form compact and discrete chromosomes. The histone N-terminal tails that extend from the nucleosome core act as docking sites for many proteins through diverse post-translational modifications, regulating various DNA transactions. In this report, we present evidence that the nucleosomes can positively regulate the enzymatic activity of Rad27 (yeast Fen1), a major processing enzyme important for Okazaki fragment in eukaryotes. We found that individual histones, histone octamers, and nucleosomes are able to stimulate Rad27 in a manner dependent on the N-terminal tails of histones. Kinetic analyses suggest that an increase in catalytic efficiency of Rad27 was mainly due to increased affinity between DNA substrates and Rad27. It appears that the physical interaction in vivo between histones and Rad27 results in the enrichment of Rad27 in the vicinity of chromatin, increasing the availability of Rad27 for various DNA metabolisms. These results indicate that nucleosomes are not a mere structural component of chromatin, but an active regulator of DNA metabolisms that serves to ensure the efficient and faithful processing of structural intermediates arising during DNA transactions.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea.
authors.forename: Buki
authors.identifier: 0000-0002-7860-0458
authors.initials: B
authors.lastname: Kwon
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea.
authors.forename: Palinda Ruvan
authors.initials: PR
authors.lastname: Munashingha
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea.
authors.forename: Yong-Keol
authors.initials: YK
authors.lastname: Shin
authors.affiliation: Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Chul-Hwan
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, Korea.
authors.forename: Yeon-Soo
authors.initials: YS
authors.lastname: Seo
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism*; D045585:Flap Endonucleases / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D009154:Mutation; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D002843:Chromatin; D004271:DNA, Fungal; D006657:Histones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D045585:Flap Endonucleases; C468323:RAD27 protein, S cerevisiae
keywords: DNA replication; Okazaki fragment; Rad27; histones; nucleosomes