TDP1 PROMOTES DNA END RESECTION AT STALLED AND COLLAPSED REPLICATION FORKS AFTER GENOTOXIC INSULTS

NÉSTOR AZNAR; CAMILA GOSSO; IRENE LARRIPA; MARCELA GONZÁLEZ-CID; MARCELO DE CAMPOS NEBEL

Mar del Plata

Encuentro; Reunión Anual de las Sociedades de Biociencia 2022; 2022

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC), SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI), SOCIEDAD ARGENTINA DE FISIOLOGÍA (SAFIS)

The Topoisomerase II (Top2) poison etoposide (ETO) induces the accumulation of Top2 cleavage complexes (ccTop2), resulting in DNA end blocking adducts. Protein adducts interfere with replication. Several nucleases and hydrolases, including MRE11 and TDP1, can remove these adduct to avoid forks stalling. The relative contribution of each enzyme in this process is not clear. We evaluated the roles of MRE11 and TDP1 in the removal of ccTop2α during replication. We utilized two HeLa cell lines stably expressing a shRNA against TDP1 (TDP1kd) or a non-silencing control (NS), in the presence of a chemical inhibitor (MRE11i) of MRE11. Flow cytometry analysis of ETO-induced ccTop2α showed an increase during the S and G2-phases in TDP1kd cells (p