ATR Restrains DNA Synthesis and Mitotic Catastrophe in Response to CDC7 Inhibition

Cell Rep. 2020 Sep 1;32(9):108096. doi: 10.1016/j.celrep.2020.108096.

Abstract

DNA replication initiates from multiple origins, and selective CDC7 kinase inhibitors (CDC7is) restrain cell proliferation by limiting origin firing. We have performed a CRISPR-Cas9 genome-wide screen to identify genes that, when lost, promote the proliferation of cells treated with sub-efficacious doses of a CDC7i. We have found that the loss of function of ETAA1, an ATR activator, and RIF1 reduce the sensitivity to CDC7is by allowing DNA synthesis to occur more efficiently, notably during late S phase. We show that partial CDC7 inhibition induces ATR mainly through ETAA1, and that if ATR is subsequently inhibited, origin firing is unleashed in a CDK- and CDC7-dependent manner. Cells are then driven into a premature and highly defective mitosis, a phenotype that can be recapitulated by ETAA1 and TOPBP1 co-depletion. This work defines how ATR mediates the effects of CDC7 inhibition, establishing the framework to understand how the origin firing checkpoint functions.

Keywords: CRISPR-Cas9 screen; DNA replication; ETAA1; RIF1; cell cycle; checkpoint; functional genomics; kinase inhibitor; replication origins; replication stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Surface / genetics
  • Antigens, Surface / metabolism
  • Ataxia Telangiectasia Mutated Proteins / antagonists & inhibitors
  • Ataxia Telangiectasia Mutated Proteins / genetics
  • Ataxia Telangiectasia Mutated Proteins / metabolism*
  • Cell Cycle Proteins / antagonists & inhibitors*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line
  • DNA / biosynthesis*
  • DNA / genetics
  • DNA Replication / physiology*
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Mitosis / physiology
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism

Substances

  • Antigens, Surface
  • Cell Cycle Proteins
  • ETAA1 protein, human
  • DNA
  • CDC7 protein, human
  • ATR protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein Serine-Threonine Kinases