A Proteomic Characterization of Factors Enriched at Nascent DNA Molecules

DNA replication is facilitated by multiple factors thatconcentrate in the vicinity of replication forks. Here,we developed an approach that combines the isola-tion of proteins on nascent DNA chains with massspectrometry (iPOND-MS), allowing a comprehen-sive proteomic characterization of the human repli-some and replisome-associated factors. In additiontoknownreplisomecomponents,weprovideabroadlist of proteins that reside in the vicinity of the repli-some,someofwhichwerenotpreviouslyassociatedwith replication. For instance, our data support a linkbetween DNA replication and the Williams-Beurensyndrome and identify ZNF24 as a replication factor.In addition, we reveal that SUMOylation is wide-spread for factors that concentrate near replisomes,which contrasts with lower UQylation levels at thesesites.Thisresourceprovidesapanoramicviewoftheproteins that concentrate in the surroundings of thereplisome, which should facilitate future investiga-tions on DNA replication and genome maintenance.