The replication checkpoint protects fork stability by releasing transcribed genes from nuclear pores

Cell. 2011 Jul 22;146(2):233-46. doi: 10.1016/j.cell.2011.06.033.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / metabolism
  • Cell Nucleus / metabolism
  • Checkpoint Kinase 2
  • DNA Breaks, Double-Stranded
  • DNA Replication*
  • Hydroxyurea / pharmacology
  • Mutation
  • Nuclear Pore / metabolism*
  • Protein-Serine-Threonine Kinases / metabolism
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Transcription, Genetic*

Substances

  • Cell Cycle Proteins
  • Saccharomyces cerevisiae Proteins
  • Checkpoint Kinase 2
  • Protein-Serine-Threonine Kinases
  • RAD53 protein, S cerevisiae
  • Hydroxyurea

Associated data

  • GEO/GSE30024