Molecular and General Genetics MGG

, Volume 154, Issue 3, pp 225–230

Replication of plasmid pSC101 inEscherichia coli K12: Requirement fordnaA function

  • Kohji Hasunuma
  • Mutsuo Sekiguchi

DOI: 10.1007/BF00571277

Cite this article as:
Hasunuma, K. & Sekiguchi, M. Molec. Gen. Genet. (1977) 154: 225. doi:10.1007/BF00571277


Replication of pSC101 was analyzed by using DNA-DNA hybridization and alkaline sucrose gradient centrifugation. Mutants of thednaA gene were tested for their capacity to replicate pSC101 DNA at a non-permissive temperature. Only a small amount of radioactive precursor was incorporated into pSC101 DNA indnaA mutants at 42°C whereas active incorporation into plasmid DNA took place indnaA+ strains under the same conditions. The effect of thednaA mutation was grater on plasmid DNA synthesis than on host chromosomal DNA synthesis. The numbers of copies of pSC101 per chromosome in wild type anddnaA strains, grown at 30°C, were about 8 and 2, respectively. These results indicate that thednaA gene product is required for the replication of pSC101 DNA.

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Kohji Hasunuma
    • 1
  • Mutsuo Sekiguchi
    • 1
  1. 1.Laboratory of Molecular Genetics Department of Biology, Faculty of ScienceKyushu University 33FukuokaJapan
  2. 2.Department of Biology, College of General EducationUniversity of TokyoTokyoJapan