Chl1 helicase controls replication fork progression by regulating dNTP pools

Life Science Alliance, vol. 5, pp. e202101153

Abstract

Eukaryotic cells have evolved a replication stress response that helps to overcome stalled/collapsed replication forks and ensure proper DNA replication. The replication checkpoint protein Mrc1 plays important roles in these processes, although its functional interactions are not fully understood. Here, we show that MRC1 negatively interacts with CHL1, which encodes the helicase protein Chl1, suggesting distinct roles for these factors during the replication stress response. Indeed, whereas Mrc1 is known to facilitate the restart of stalled replication forks, we uncovered that Chl1 controls replication fork rate under replication stress conditions. Chl1 loss leads to increased RNR1 gene expression and dNTP levels at the onset of S phase likely without activating the DNA damage response. This in turn impairs the formation of RPA-coated ssDNA and subsequent checkpoint activation. Thus, the Chl1 helicase affects RPA-dependent checkpoint activation in response to replication fork arrest by ensuring proper intracellular dNTP levels, thereby controlling replication fork progression under replication stress conditions.

Authors 8

1. Amandine Batté Aachen Department of Human Genetics

   Leiden University Medical Center

   Affiliation as printed

   Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands

2. Sophie C. van der Horst Aachen Department of Human Genetics

   Leiden University Medical Center

   Affiliation as printed

   Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands

3. Mireille Tittel-Elmer Aachen Department of Human Genetics

   Leiden University Medical Center · Delft University of Technology

   Affiliation as printed

   Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands

   Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, Netherlands

4. Su Ming Sun Aachen Department of Human Genetics

   Leiden University Medical Center

   Affiliation as printed

   Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands

5. Sushma Sharma

   Umeå University

   Affiliation as printed

   Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden

6. Jolanda S. van Leeuwen

   University of Lausanne

   Affiliation as printed

   Center for Integrative Genomics, Université de Lausanne, Lausanne-Dorigny, Switzerland

7. Andrei Chabes

   Umeå University

   Affiliation as printed

   Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden

8. Haico van Attikum corresponding Aachen Department of Human Genetics

   Leiden University Medical Center

   Affiliation as printed

   Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands