Biology subjects

Bekesi, A.

Publications and source records attributed to Bekesi, A..

3 recordsLinked to original sources

bioRxiv2026

Recognizing dUTPase as a mitotic factor essential for early embryonic development

dUTPase is universally regarded as a metabolic sanitizing enzyme that protects genomes by preventing the incorporation of uracil into DNA. Despite its essentiality across eukaryotes, no function beyond nucleotide sanitization has been demonstrated. Here, we uncover a conserved, non-canonical role for dUTPase as a regulator of mitosis. Using Drosophila and mouse models, we demonstrate that dUTPase loss causes early embryonic lethality characterized by severe mitotic failure that, cannot be rescued by disabling uracil-DNA repair, uncoupling dUTPase essentiality from DNA repair pathways. Mechanistically, dUTPase dynamically associates with the mitotic spindle and centrosomes, and its depletion induces centrosome amplification and chromosome segregation defects. Beyond cell division, dUTPase dosage bidirectionally controls cell migration, linking its mitotic function to cellular behaviors relevant for metastasis. Together, our findings redefine dUTPase as a moonlighting mitotic factor that coordinates centrosome integrity and spindle dynamics, expanding its known repertoire beyond nucleotide metabolism. HighlightsdUTPase deficiency leads to mitotic defects during early embryonic development in both Drosophila and mouse models dUTPase shows dynamic spatiotemporal localization associated with microtubules through mitosis dUTPase is essential for the normal number and intracellular localization of centrosomes dUTPase deficiency counteracts while its overexpression enhances cell migration

molecular biology↗

bioRxiv2025

Thymidylate synthase inhibitory drugs induce p53-dependent pathways differently

Thymidylate synthase (TS) is a key enzyme in thymidylate biosynthesis and an established target of chemotherapeutics such as 5-fluoro-2-deoxyuridine (5FdUR) and raltitrexed (RTX). Inhibition of TS disrupts the dUTP:dTTP balance, leading to uracil misincorporation, futile base excision repair cycles, DNA strand breaks, and ultimately cell death. Beyond its catalytic role, TS also binds RNA, autoregulating its own translation and interacting with transcripts such as p53 and c-myc, thereby linking TS activity to broader post-transcriptional regulatory networks. These interactions, together with regulation by miRNAs and lncRNAs, suggest that TS inhibition may provoke cellular responses extending beyond DNA metabolism. Non-coding RNAs, including miRNAs, snoRNAs, snRNAs, and lncRNAs, may play critical roles in shaping these outcomes. To dissect these mechanisms, we investigated the transcriptomic effects of TS inhibition in mismatch repair-deficient, UNG-inhibited HCT116 colon cancer cells treated with 5FdUR or RTX. Both drugs induced DNA damage responses and S-phase arrest, yet displayed distinct transcriptional signatures. Moreover, TS-RNA immunoprecipitation sequencing revealed direct RNA-binding targets of TS, highlighting its contribution as a post-transcriptional regulator. Our findings underscore the multifaceted impact of TS inhibition, linking enzymatic disruption to RNA-level regulation and revealing drug-specific differences in cellular responses.

cancer biology↗

bioRxiv2020

Genome-wide alterations of uracil distribution patterns in human DNA upon chemotherapeutic treatments

Numerous anti-cancer drugs perturb thymidylate biosynthesis and lead to genomic uracil incorporation contributing to their antiproliferative effect. Still, it is not yet characterized if uracil incorporations have any positional preference. Here, we aimed to uncover genome-wide alterations in uracil pattern upon drug-treatment in human cancer cell-line HCT116. We developed a straightforward U-DNA sequencing method (U-DNA-Seq) that was combined with in situ super-resolution imaging. Using a novel robust analysis pipeline, we found broad regions with elevated probability of uracil occurrence both in treated and non-treated cells. Correlation with chromatin markers and other genomic features shows that non-treated cells possess uracil in the late replicating constitutive heterochromatic regions, while drug treatment induced a shift of incorporated uracil towards more active/functional segments. Data were corroborated by colocalization studies via dSTORM microscopy. This approach can also be applied to study the dynamic spatio-temporal nature of genomic uracil.

biochemistry↗