Objective The project outlined here investigates the molecular mechanisms of the critical final steps of homologous recombination (HR) based DNA repair, a pathway that supports the error-free repair of double-stranded DNA breaks (DSBs). In HR, the broken DNA ends are processed and homologous DNA provides a template for repair. Engagement of both processed ends leads to the formation of a double Holliday-junction (DHJ) structure. DHJ can be resolved by enzymatic cleavage or dissolved by the concerted action of a specialized group of helicases (RecQ-family helicases including Bloom’s syndrome helicase (BLM)) and Type I topoisomerases (e.g. TOP3A). In humans the ‘dissolvasome complex’ consists of BLM, TOP3A and regulatory proteins (RMI1, RMI2), called the BTR complex. The BTR complex dissolves DHJ by 1. convergent branch migration of the two independent HJs and 2. decatenation of the final hemicatenate structure. Thus, dissolution solely results non-crossover products, which is necessary to avoid chromosomal rearrangements. What is the mechanism of HJ migration? What are the exact roles of the subunits of the BTR complex? How long can a HJ migrate (i.e. how processive is the ‘dissolvasome’)? How specific is the DHJ migration to the BTR complex compared to other human RecQ helicases? Here we aim to address these questions by using state-of-the-art single-molecule and solution biophysical and biochemical techniques. We will generate a previously inaccessible mobile HJ substrate integrated into λ-bacteriophage DNA. We will follow the processes underlying HJ migration by fluorescently labeling the BTR complex, HJ position and DNA end in total internal reflection fluorescence (TIRF) microscopy combined with microfluidics. Elucidation of the detailed roles of the BTR components in HJ branch migration will help us to understand their roles in genome maintenance. Fields of science natural sciencesphysical sciencesclassical mechanicsfluid mechanicsmicrofluidicsnatural sciencesbiological sciencesgeneticsDNAnatural sciencesphysical sciencesopticsmicroscopynatural sciencesbiological sciencesgeneticsgenomesnatural sciencesbiological sciencesbiochemistrybiomoleculesproteinsenzymes Programme(s) H2020-EU.1.3. - EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions Main Programme H2020-EU.1.3.2. - Nurturing excellence by means of cross-border and cross-sector mobility Topic(s) MSCA-IF-2014-EF - Marie Skłodowska-Curie Individual Fellowships (IF-EF) Call for proposal H2020-MSCA-IF-2014 See other projects for this call Funding Scheme MSCA-IF-EF-RI - RI – Reintegration panel Coordinator EOTVOS LORAND TUDOMANYEGYETEM Net EU contribution € 146 239,20 Address Egyetem ter 1-3 1053 Budapest Hungary See on map Region Közép-Magyarország Budapest Budapest Activity type Higher or Secondary Education Establishments Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Other funding € 0,00
