title: dNTP pools determine fork progression and origin usage under replication stress.
abstract: Intracellular deoxyribonucleoside triphosphate (dNTP) pools must be tightly regulated to preserve genome integrity. Indeed, alterations in dNTP pools are associated with increased mutagenesis, genomic instability and tumourigenesis. However, the mechanisms by which altered or imbalanced dNTP pools affect DNA synthesis remain poorly understood. Here, we show that changes in intracellular dNTP levels affect replication dynamics in budding yeast in different ways. Upregulation of the activity of ribonucleotide reductase (RNR) increases elongation, indicating that dNTP pools are limiting for normal DNA replication. In contrast, inhibition of RNR activity with hydroxyurea (HU) induces a sharp transition to a slow-replication mode within minutes after S-phase entry. Upregulation of RNR activity delays this transition and modulates both fork speed and origin usage under replication stress. Interestingly, we also observed that chromosomal instability (CIN) mutants have increased dNTP pools and show enhanced DNA synthesis in the presence of HU. Since upregulation of RNR promotes fork progression in the presence of DNA lesions, we propose that CIN mutants adapt to chronic replication stress by upregulating dNTP pools.
authors.affiliation: Institute of Human Genetics, CNRS UPR 1142, Montpellier, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Poli
authors.forename: Olga
authors.initials: O
authors.lastname: Tsaponina
authors.forename: Laure
authors.initials: L
authors.lastname: Crabbé
authors.forename: Andrea
authors.initials: A
authors.lastname: Keszthelyi
authors.forename: Véronique
authors.initials: V
authors.lastname: Pantesco
authors.forename: Andrei
authors.initials: A
authors.lastname: Chabes
authors.forename: Armelle
authors.initials: A
authors.lastname: Lengronne
authors.forename: Philippe
authors.initials: P
authors.lastname: Pasero
mesh_terms: D001973:Bromodeoxyuridine; D004249:DNA Damage; D004261:DNA Replication; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D003853:Deoxyribonucleosides / Q000378:metabolism*; D006918:Hydroxyurea / Q000494:pharmacology; D047468:Immunoprecipitation; D018741:Replication Origin; D012264:Ribonucleotide Reductases / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
chemical_list: D004271:DNA, Fungal; D003853:Deoxyribonucleosides; D012264:Ribonucleotide Reductases; D001973:Bromodeoxyuridine; D006918:Hydroxyurea