Objective The RecQ family of helicases, including BLM in human and its Saccharomyces cerevisiae homolog Sgs1, have important roles in maintaining genome stability. Sgs1 plays a specific role in response to intra-S DNA damage by resolving the pseudo double HJs resulting from replication-related sister chromatid junctions (SCJs). These catenated DNA structures are thought to represent template switch (TS) intermediates. Although the molecular mechanism is largely unknown, TS is thought to represent a major mechanism to bypass damage during replication. We recently showed that two genetic TS pathways, both of which involve homologous recombination (HR) factors, can lead to bypass of damage by means of SCJs and that their choice is regulated by sumoylation of a key replication factor, PCNA. We also found that the main TS pathway operating in cells involves the coordinated action of HR with the post-replication repair proteins Rad18, Rad5 and Mms2-Ubc13, which exert their role in promoting SCJ formation by means of ubiquitilating PCNA. Previously we showed that the resolution activity of Sgs1 and Top3 is regulated by Ubc9- and Mms21-dependent sumoylation, but the SUMO targets implicated with Sgs1 in this process remained unknown. In this project we plan to characterize the pathways that lead to TS and to understand the factors that promote different steps of this process and their regulation, using in vivo and in vitro approaches. We will attempt to understand how sumoylation is activated by intra-S damage and to address how the formation and subsequent resolution of these X-structures is coordinated with chromatin remodeling functions and topological transitions. We will characterize the X-shaped molecules formed during replication and we will attempt their visualization. Fields of science natural sciencesbiological sciencesgeneticsDNAnatural sciencesbiological sciencesbiochemistrybiomoleculesproteinsnatural sciencesbiological sciencesgeneticsgenomes Keywords intra-S repair template switch SUMO and Ubiquitin modifications Replication checkpoint pseudo double Holliday Junctions Programme(s) FP7-IDEAS-ERC - Specific programme: "Ideas" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Topic(s) ERC-SG-LS1 - ERC Starting Grant - Molecular and Structural Biology and Biochemistry Call for proposal ERC-2009-StG See other projects for this call Funding Scheme ERC-SG - ERC Starting Grant Host institution IFOM-ISTITUTO FONDAZIONE DI ONCOLOGIA MOLECOLARE ETS EU contribution € 1 841 600,00 Address VIA ADAMELLO 16 20139 Milano Italy See on map Region Nord-Ovest Lombardia Milano Activity type Research Organisations Principal investigator Dana Branzei (Dr.) Administrative Contact Carlo Raimondi Cominesi (Mr.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data Beneficiaries (1) Sort alphabetically Sort by EU Contribution Expand all Collapse all IFOM-ISTITUTO FONDAZIONE DI ONCOLOGIA MOLECOLARE ETS Italy EU contribution € 1 841 600,00 Address VIA ADAMELLO 16 20139 Milano See on map Region Nord-Ovest Lombardia Milano Activity type Research Organisations Principal investigator Dana Branzei (Dr.) Administrative Contact Carlo Raimondi Cominesi (Mr.) Links Contact the organisation Opens in new window Website Opens in new window Total cost No data