The repair of Topoisomerase 1 and 2 DNA-protein crosslinks in vivo

doctoral thesis

• Title (croatian): Popravak križnih veza između DNA i topoizomeraza 1 i 2
• Author: Ivan Antičević
• Mentor: Marta Popović (mentor)
• Committee member: Tvrtko Smital (predsjednik povjerenstva)
• Committee member: Dragomira Majhen (član povjerenstva)
• Committee member: Marko Močibob (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2023-11-17, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 577 - Biochemistry. Molecular biology. Biophysics

Abstract

DNA-protein crosslinks (DPCs) are frequent and damaging DNA lesions that affect all DNA transactions, which can lead to the formation of DSBs (double-strand DNA breaks), genomic instability and cell death. At the organismal level, impaired DPC repair (DPCR) is associated with cancer, aging, and neurodegeneration. Repair of the two most abundant enzymatic DPCs, involving topoisomerase 1 and 2 was studied in cell models, but data from organisms are still limited. Here, using a zebrafish model and human cells, we show that endogenous TOP1-DPCs are repaired by TDP1 and SPRTN through independent pathways. Notably, chemically induced TOP1-DPCs, using camptothecin or formaldehyde, require an epistatic action of both enzymes, and effectively prevent the accumulation of TOP1-DPC-related damage. Furthermore, we identified the zebrafish Tdp2 orthologue, Tdp2b, as the enzyme responsible for the removal of Top2-DPC residues. Reduced Tdp2 function, observed in both, living organisms and cellular models, causes significant phenotypic changes. This study provides the first insights into the repair of TOP1- and TOP2-DPCs in vivo.

Abstract (croatian)

Križne veze proteina i DNA (eng. DPCs) su česte i štetne lezije DNA koje ometaju sve procese na DNA, što može dovesti do pojave dvostrukih lomova, genomske nestabilnosti i stanične smrti. Na razini organizma, neefikasan popravak križnih veza proteina i DNA povezan je s nastankom tumora, starenjem i neurodegeneracijom. Dok je popravak najčešćih enzimskih DPC-a, Topoizomeraze 1 i 2, pručavan u staničnim modelima, podaci o ovom popravku u organizmima još uvijek su nedostatni. U ovom istraživanju, koristeći model ribe zebrice i ljudske stanične kulture , pokazali smo in vivo da se endogeni popravak TOP1-DPC odvija putem enzima TDP1 i SPRTN, pri čemu ti enzimi djeluju neovisno jedan o drugome. Nadalje, DPC-evi s TOP1 inducirani kemijski, korištenjem kamptotecina ili formaldehida, zahtijevaju međusobno ovisno djelovanje oba enzima kako bi se učinkovito spriječilo nakupljanje oštećenja povezanih s TOP1-DPC-ovima. U ovom radu, pokazali smo kako je zebričin Tdp2 ortolog, Tdp2b, enzim odgovoran za uklanjanje ostataka Top2-DPC-a s DNA. Smanjenje aktivnosti Tdp2, kako u živim organizmima tako i u staničnim modelima, rezultira značajnim fenotipskim promjenama. Ovo istraživanje pruža prve uvide u mehanizme popravka TOP1- i TOP2-DPC-eva in vivo.

• Keywords: TDP1; TDP2; Topoisomerase 1; Topoisomerase 2; DPC; zebrafish; SPRTN; DNA repair
• Keywords (croatian): TDP1; TDP2; Topoizomeraza 1; Topoizomeraza 2; DPC; zebrica; SPRTN; DNA popravak
• Language: english
• URN:NBN: urn:nbn:hr:217:039955
• Promotion: 2023
• Project: Number: UIP-05-2017; Title: Metode za interpretaciju medicinskih snimki za detaljnu analizu zdravlja srca; Title: Medical Image Interpretation Methods for a Detailed Heart Health Analysis; Leader: Irena Galić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: Nema
• Study programme: Title: Doctoral study; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti u području prirodnih znanosti (doktor/doktorica znanosti u području prirodnih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2024-11-17
• Created on: 2023-11-29 12:15:35