Send to

Choose Destination
Nucleic Acids Res. 2016 Dec 15;44(22):10676-10690. Epub 2016 Sep 26.

Nucleolytic processing of aberrant replication intermediates by an Exo1-Dna2-Sae2 axis counteracts fork collapse-driven chromosome instability.

Author information

The F.I.R.C. Institute of Molecular Oncology (IFOM) Foundation, Via Adamello 16, 20139 Milan, Italy.
Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Calle Zacarías González 2, 37007 Salamanca, Spain.
Centro de Investigaciones Biológicas (CIB-CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain.
Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Calle Zacarías González 2, 37007 Salamanca, Spain


Problems during DNA replication underlie genomic instability and drive malignant transformation. The DNA damage checkpoint stabilizes stalled replication forks thus counteracting aberrant fork transitions, DNA breaks and chromosomal rearrangements. We analyzed fork processing in checkpoint deficient cells by coupling psoralen crosslinking with replication intermediate two-dimensional gel analysis. This revealed a novel role for Exo1 nuclease in resecting reversed replication fork structures and counteracting the accumulation of aberrant intermediates resembling fork cleavage products. Genetic analyses demonstrated a functional interplay of Exo1 with Mus81, Dna2 and Sae2 nucleases in promoting cell survival following replication stress, suggestive of concerted nucleolytic processing of stalled forks. While Mus81 and other Structure Specific Endonucleases do not contribute to obvious collapsed fork transitions, Dna2 promotes reversed fork resection likely by facilitating Exo1 access to nascent strands. Instead, Sae2 cooperates with Exo1 in counteracting putative fork cleavage events linked to double strand breaks formation and increased gross chromosomal rearrangement rates. Our data indicate that in checkpoint deficient cells diverse nuclease activities interface to eliminate aberrant replication intermediates and prevent chromosome instability.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center