title: Intrinsic coupling of lagging-strand synthesis to chromatin assembly.
abstract: Fifty per cent of the genome is discontinuously replicated on the lagging strand as Okazaki fragments. Eukaryotic Okazaki fragments remain poorly characterized and, because nucleosomes are rapidly deposited on nascent DNA, Okazaki fragment processing and nucleosome assembly potentially affect one another. Here we show that ligation-competent Okazaki fragments in Saccharomyces cerevisiae are sized according to the nucleosome repeat. Using deep sequencing, we demonstrate that ligation junctions preferentially occur near nucleosome midpoints rather than in internucleosomal linker regions. Disrupting chromatin assembly or lagging-strand polymerase processivity affects both the size and the distribution of Okazaki fragments, suggesting a role for nascent chromatin, assembled immediately after the passage of the replication fork, in the termination of Okazaki fragment synthesis. Our studies represent the first high-resolution analysis--to our knowledge--of eukaryotic Okazaki fragments in vivo, and reveal the interconnection between lagging-strand synthesis and chromatin assembly.
authors.affiliation: Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Smith
authors.forename: Iestyn
authors.initials: I
authors.lastname: Whitehouse
mesh_terms: D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D004247:DNA / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000172:deficiency / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D059014:High-Throughput Nucleotide Sequencing; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D009707:Nucleosomes; C022262:Okazaki fragments; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA; D004258:DNA Polymerase III; D011088:DNA Ligases; D000072481:DNA Ligase ATP