Molecular Genetics and Genomics

, Volume 275, Issue 5, pp 460–470 | Cite as

Enhanced gene targeting frequency in ku70 and ku80 disruption mutants of Aspergillus sojae and Aspergillus oryzae

  • Tadashi TakahashiEmail author
  • Tsutomu Masuda
  • Yasuji Koyama
Original Paper


In the koji molds Aspergillus sojae and Aspergillus oryzae, exogenous DNA is integrated in the genome, in most cases irrespective of the sequence homology, suggesting that DNA integration occurs predominantly through a nonhomologous end joining pathway where two ku genes, namely, ku70 and ku80, play a key role. To determine the effect of ku gene disruption on the gene targeting frequency, we constructed ku70-, ku80-, and ku70–ku80-disrupted strains of A. sojae and A. oryzae. The gene targeting frequency of the tannase gene in ku70 and ku80 strains of both Aspergillus species was markedly enhanced as compared with that of the parental strains. The gene targeting frequency of the aflR and ku80 genes was also enhanced in an A. sojae ku70 background. Therefore, the koji mold strains with ku-disrupted genes will be excellent tools as hosts for efficient gene targeting.


Gene targeting Nonhomologous end joining pathway ku70 ku80 



We are grateful to Professor Hideo Takahashi, Mr. Osamu Hatamoto, and Dr. Genryou Umitsuki for their helpful discussion and beneficial advice, and Mr. Yukio Senou for the technical assistance provided.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Tadashi Takahashi
    • 1
    Email author
  • Tsutomu Masuda
    • 1
  • Yasuji Koyama
    • 1
  1. 1.Noda Institute for Scientific ResearchNoda City, ChibaJapan

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