title: The replication checkpoint protects fork stability by releasing transcribed genes from nuclear pores.
abstract: Transcription hinders replication fork progression and stability, and the Mec1/ATR checkpoint protects fork integrity. Examining checkpoint-dependent mechanisms controlling fork stability, we find that fork reversal and dormant origin firing due to checkpoint defects are rescued in checkpoint mutants lacking THO, TREX-2, or inner-basket nucleoporins. Gene gating tethers transcribed genes to the nuclear periphery and is counteracted by checkpoint kinases through phosphorylation of nucleoporins such as Mlp1. Checkpoint mutants fail to detach transcribed genes from nuclear pores, thus generating topological impediments for incoming forks. Releasing this topological complexity by introducing a double-strand break between a fork and a transcribed unit prevents fork collapse. Mlp1 mutants mimicking constitutive checkpoint-dependent phosphorylation also alleviate checkpoint defects. We propose that the checkpoint assists fork progression and stability at transcribed genes by phosphorylating key nucleoporins and counteracting gene gating, thus neutralizing the topological tension generated at nuclear pore gated genes.
authors.affiliation: Fondazione Istituto FIRC di Oncologia Molecolare (IFOM) at IFOM-IEO Campus, Via Adamello 16, 20139 Milan, Italy. rodrigo.bermejo@ifom-ieo-campus.it
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Bermejo
authors.forename: Thelma
authors.initials: T
authors.lastname: Capra
authors.forename: Rachel
authors.initials: R
authors.lastname: Jossen
authors.forename: Arianna
authors.initials: A
authors.lastname: Colosio
authors.forename: Camilla
authors.initials: C
authors.lastname: Frattini
authors.forename: Walter
authors.initials: W
authors.lastname: Carotenuto
authors.forename: Andrea
authors.initials: A
authors.lastname: Cocito
authors.forename: Ylli
authors.initials: Y
authors.lastname: Doksani
authors.forename: Hannah
authors.initials: H
authors.lastname: Klein
authors.forename: Belén
authors.initials: B
authors.lastname: Gómez-González
authors.forename: Andrés
authors.initials: A
authors.lastname: Aguilera
authors.forename: Yuki
authors.initials: Y
authors.lastname: Katou
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Shirahige
authors.forename: Marco
authors.initials: M
authors.lastname: Foiani
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D064447:Checkpoint Kinase 2; D053903:DNA Breaks, Double-Stranded; D004261:DNA Replication; D006918:Hydroxyurea / Q000494:pharmacology; D009154:Mutation; D022022:Nuclear Pore / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae; D006918:Hydroxyurea