Rif1 provides a new DNA-binding interface for the Bloom syndrome complex to maintain normal replication

EMBO J. 2010 Sep 15;29(18):3140-55. doi: 10.1038/emboj.2010.186. Epub 2010 Aug 13.


BLM, the helicase defective in Bloom syndrome, is part of a multiprotein complex that protects genome stability. Here, we show that Rif1 is a novel component of the BLM complex and works with BLM to promote recovery of stalled replication forks. First, Rif1 physically interacts with the BLM complex through a conserved C-terminal domain, and the stability of Rif1 depends on the presence of the BLM complex. Second, Rif1 and BLM are recruited with similar kinetics to stalled replication forks, and the Rif1 recruitment is delayed in BLM-deficient cells. Third, genetic analyses in vertebrate DT40 cells suggest that BLM and Rif1 work in a common pathway to resist replication stress and promote recovery of stalled forks. Importantly, vertebrate Rif1 contains a DNA-binding domain that resembles the αCTD domain of bacterial RNA polymerase α; and this domain preferentially binds fork and Holliday junction (HJ) DNA in vitro and is required for Rif1 to resist replication stress in vivo. Our data suggest that Rif1 provides a new DNA-binding interface for the BLM complex to restart stalled replication forks.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Carrier Proteins / antagonists & inhibitors
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line
  • Chickens
  • DNA / genetics
  • DNA / metabolism*
  • DNA Replication*
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • HeLa Cells
  • Humans
  • Immunoprecipitation
  • Kidney / cytology
  • Kidney / metabolism
  • Molecular Sequence Data
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • RNA, Small Interfering / pharmacology
  • RecQ Helicases / antagonists & inhibitors
  • RecQ Helicases / genetics
  • RecQ Helicases / metabolism*
  • Sequence Homology, Amino Acid
  • Telomere-Binding Proteins / antagonists & inhibitors
  • Telomere-Binding Proteins / genetics
  • Telomere-Binding Proteins / metabolism*


  • Carrier Proteins
  • DNA-Binding Proteins
  • Nuclear Proteins
  • RMI1 protein, human
  • RMI2 protein, human
  • RNA, Small Interfering
  • Rif1 protein, human
  • Telomere-Binding Proteins
  • DNA
  • Bloom syndrome protein
  • RecQ Helicases