CRL2Lrr1 promotes unloading of the vertebrate replisome from chromatin during replication termination

  1. Johannes C. Walter1,3
  1. 1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA;
  2. 2Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany;
  3. 3Howard Hughes Medical Institute, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
  1. Corresponding authors: johannes_walter{at}hms.harvard.edu, markus.raeschle{at}biologie.uni-kl.de
  1. 6 These authors contributed equally to this work.

  • Present addresses: 4Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA; 5Department of Molecular Genetics, Technical University of Kaiserslautern, 67653 Kaiserslautern, Germany.

Abstract

A key event during eukaryotic replication termination is the removal of the CMG helicase from chromatin. CMG unloading involves ubiquitylation of its Mcm7 subunit and the action of the p97 ATPase. Using a proteomic screen in Xenopus egg extracts, we identified factors that are enriched on chromatin when CMG unloading is blocked. This approach identified the E3 ubiquitin ligase CRL2Lrr1, a specific p97 complex, other potential regulators of termination, and many replisome components. We show that Mcm7 ubiquitylation and CRL2Lrr1 binding to chromatin are temporally linked and occur only during replication termination. In the absence of CRL2Lrr1, Mcm7 is not ubiquitylated, CMG unloading is inhibited, and a large subcomplex of the vertebrate replisome that includes DNA Pol ε is retained on DNA. Our data identify CRL2Lrr1 as a master regulator of replisome disassembly during vertebrate DNA replication termination.

Keywords

Footnotes

  • Received October 9, 2016.
  • Accepted January 30, 2017.

This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genesdev.cshlp.org/site/misc/terms.xhtml). After six months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.

Related Article

| Table of Contents

Life Science Alliance