Requirement of S. pombe exonuclease II, a homologue of S. cerevisiae Sep1, for normal mitotic growth and viability

Curr Genet. 1996 Sep;30(4):284-93. doi: 10.1007/s002940050134.


Exonuclease II (ExoII) from Schizosaccharomyces pombe is a 5'-->3' single-stranded DNA exonuclease. We have cloned its gene, exo2, whose nucleotide sequence revealed that ExoII is a homologue of the multifunctional Saccharomyces cerevisiae Sep1 protein (also called Kem1, Xrn1, Rar5, Dst2). S. pombe exo2 null mutants were cold-sensitive for growth, had increased cell size at the restrictive temperature, were hypersensitive to the mitotic inhibitor thiabendazol and to caffeine, and died rapidly in stationary phase. Many of these phenotypes are similar to those of sep1 (kem1 or xrn1) mutants of S. cerevisiae. In contrast, the exo2 mutation had only a moderate effect on progression through meiosis and no significant effect on meiotic recombination. We discuss possible functions of the multifunctional ExoII protein.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Benzimidazoles / toxicity
  • Caffeine / pharmacology
  • Carbamates*
  • Cell Division / genetics
  • Cloning, Molecular
  • Deoxyribonucleases / genetics*
  • Exodeoxyribonucleases / genetics*
  • Exodeoxyribonucleases / isolation & purification
  • Exoribonucleases*
  • Fungal Proteins / genetics*
  • Gene Deletion
  • Meiosis
  • Mitosis* / drug effects
  • Molecular Sequence Data
  • Mutagens / toxicity
  • Mutation
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces / enzymology*
  • Schizosaccharomyces / genetics*
  • Schizosaccharomyces / growth & development
  • Sequence Homology, Amino Acid
  • Spores, Fungal / genetics


  • Benzimidazoles
  • Carbamates
  • Fungal Proteins
  • Mutagens
  • Saccharomyces cerevisiae Proteins
  • Caffeine
  • Deoxyribonucleases
  • Exodeoxyribonucleases
  • Exoribonucleases
  • XRN1 protein, S cerevisiae
  • exodeoxyribonuclease II
  • carbendazim

Associated data

  • GENBANK/L35232