CpG Islands: Starting Blocks for Replication and Transcription

• DOI: 10.1371/journal.pgen.1000454
• Publication Date: 2009-04-09T22:16:06Z
• Authors: Marie-Noëlle Prio...
• Keywords: DNA Replication; Mammals; 0301 basic medicine; Transcription, Genetic; Replication Origin; QH426-470; [SDV.GEN.GH] Life Sciences [q-bio]/Genetics/Human genetics; Mice; 03 medical and health sciences; [SDV.GEN.GH]Life Sciences [q-bio]/Genetics/Human genetics; Perspective; Genetics; Animals; Humans; CpG Islands; Embryonic Stem Cells

ORI sequences. A few months ago, common features shared by large groups of ORIs were extracted from a large-scale mapping of replication origins based on the resistance of short nascent strands (SNS) to l-exonuclease digestion [5]. This study, conducted in HeLa cells and covering approximately 1% of the human genome, showed that origin density is strongly correlated with genomic landscapes, with clusters of closely spaced origins in GC-rich regions and no or only few origins in GC-poor regions. Moreover, half of the origins were mapped within or near CpG islands. In this issue of PLoS Genetics, a study by Sequeira-Mendes et al. extends this obser