2020 journal article
Arabidopsis DNA Replication Initiates in Intergenic, AT-Rich Open Chromatin(1)([OPEN])
PLANT PHYSIOLOGY, 183(1), 206–220.
MeSH headings : Arabidopsis / genetics; Arabidopsis / metabolism; Arabidopsis Proteins / genetics; Arabidopsis Proteins / metabolism; Chromatin / metabolism; DNA Replication / genetics; DNA Replication / physiology; DNA, Plant / metabolism; DNA, Plant / physiology; Replication Origin / genetics; Replication Origin / physiology
TL;DR:
A new functional assay to label and map very early replicating loci that must, by definition, include at least a subset of replication origins, and indicates that IRs are associated with accessible chromatin.
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open access via www.plantphysiol.org (publisher PDF)
UN Sustainable Development Goal Categories
3. Good Health and Well-being
(Web of Science)
Source: Web Of Science
Added: June 15, 2020
DNA replication initiation sites in plants associate most strongly with AT-rich and highly accessible chromatin, and not with genes or a particular epigenetic signature. The selection and firing of DNA replication origins play key roles in ensuring that eukaryotes accurately replicate their genomes. This process is not well documented in plants due in large measure to difficulties in working with plant systems. We developed a new functional assay to label and map very early replicating loci that must, by definition, include at least a subset of replication origins. Arabidopsis (Arabidopsis thaliana) cells were briefly labeled with 5-ethynyl-2′-deoxy-uridine, and nuclei were subjected to two-parameter flow sorting. We identified more than 5500 loci as initiation regions (IRs), the first regions to replicate in very early S phase. These were classified as strong or weak IRs based on the strength of their replication signals. Strong initiation regions were evenly spaced along chromosomal arms and depleted in centromeres, while weak initiation regions were enriched in centromeric regions. IRs are AT-rich sequences flanked by more GC-rich regions and located predominantly in intergenic regions. Nuclease sensitivity assays indicated that IRs are associated with accessible chromatin. Based on these observations, initiation of plant DNA replication shows some similarity to, but is also distinct from, initiation in other well-studied eukaryotic systems.