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Emerging evidence from genome-wide analyses reveals that DNA methylation, an epigenetic modification associated with the repression of gene expression, can also promote transcriptional activation.
DNA replication begins with prereplication-complex formation at origins and is followed by helicase activation to unwind DNA at the replication fork. This Perspective compares bacterial DnaB and eukaryotic MCM2–7 helicase-loading mechanisms and discusses emerging data supporting current models of how two MCM2–7 complexes are loaded to form a double hexamer.