A yeast gene product, Fob1 protein, required for both replication fork blocking and recombinational hotspot activities

Genes Cells. 1996 May;1(5):465-74. doi: 10.1046/j.1365-2443.1996.d01-256.x.


Background: In the rRNA gene cluster on the Saccharomyces cerevisiae chromosome XII, a unique site that blocks progression of the replication fork exists in a single unit of the repeats. The site RFB (replication fork blocking) is located within one of two cis-elements present in a nontranscribed region of each repeated unit, which are required for obtaining maximal activity of a hotspot (HOT1) dependent recombination.

Results: To investigate the correlation between replication fork blocking at RFB and homologous recombination at HOT1, we have isolated Hot1-defective mutants and examined their ability for fork blocking at RFB. Amongst 23 isolated mutants, four were found to be defective in both abilities. Genetic analysis of the mutants reveals that a single mutation, named fob1 (fork blocking less), is responsible for the defects in both abilities. The FOB1 gene is located on chromosome IV and has no homology with any other genes listed in DNA data banks.

Conclusion: The pleiotropic effect of the fob1 mutation suggests that homologous recombination at HOT1 is closely linked with DNA replication fork blocking event at RFB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Chromosome Mapping
  • DNA Replication*
  • DNA, Fungal / biosynthesis
  • DNA, Fungal / genetics
  • DNA-Binding Proteins*
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism*
  • Genes, Fungal
  • Molecular Sequence Data
  • Multigene Family
  • Mutation
  • Recombination, Genetic*
  • Repetitive Sequences, Nucleic Acid
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*


  • DNA, Fungal
  • DNA-Binding Proteins
  • FOB1 protein, S cerevisiae
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins

Associated data

  • GENBANK/AF013245