H4S47 O-GlcNAcylation regulates the activation of mammalian replication origins

The transmission and maintenance of genetic information in eukaryotic cells rely on the faithful duplication of the entire genome. In each round of division, excessive replication origiNS are licensed, while only a fraction is activated to give rise to bi-directional replication forks travelling in the context of chromatin. However, it remaiNS elusive how eukaryotic replication origiNS are selectively activated. Here we demoNStrate that O-GlcNAc traNSferase (OGT) enhances replication initiation by catalysing H4S47 O-GlcNAcylation. Mutation of H4S47 impairs DBF4-dependent protein kinase (DDK) recruitment on chromatin, causing compromised phosphorylation of replicative helicase mini-chromosome maintenance (MCM) complex. Meanwhile, our short nascent-strand sequencing (SNS-seq) confirms the important role of H4S47 O-GlcNAcylation in origin activation. Together, H4S47 O-GlcNAcylation directs origin activation through facilitating MCM phosphorylation, and this may shed light on the spatial and temporal control of DNA replication by the dynamically changing chromatin environment. Overall design: Analysis active replication origins in HEK293T cells expressing H4WT or H4S47A.