Intramolecular DNA Triplexes in Escherichia. coli

Methylase를 사용한 Escherichia coli에서 Triplex 존재에 관한 연구

  • Rhim, Hyangshuk (Research Institute of Molecular Genetics, College of Medicine, the Catholic University of Korea) ;
  • Kim, Sungjo (Graduate School of Biotechnology, Korea University) ;
  • Kang, Seongman (Graduate School of Biotechnology, Korea University)
  • 임향숙 (가톨릭대학교 의과학원 분자유전학연구소) ;
  • 김성조 (고려대학교 생명공학원) ;
  • 강성만 (고려대학교 생명공학원)
  • Received : 1998.09.28
  • Accepted : 1998.11.01
  • Published : 1998.12.01


We have introduced a genetic assay to study the existence of intramolecular triplexes in Escherichia coli. A plasmid containing the gene that encodes a temperature-sensitive EcoRI methylase was cotransformed with different plasmids containing inserts, $(G)_9AATTC(G)_9$ and $(GAA)_9TTC(GAA)_8$, that are able to form intramolecular triplexes in vitro. Inhibition of methylation in vivo was found for $(G)_9AATTC(G)_9$ and $(GAA)_9TTC(GAA)_8$, suggesting that the pur pyr sequences adopt unusual strucures in E. coli. In addition, experiments using two dimensional gel electrophoresis confirmed that intramolecular triplexes are formed for the pur pyr sequences under negative supercoiling. These results demonstrate the existence of intramolecular triplexes in E. coli.


E. coli;EcoRI methylase;intramolecular triplexes;pur.pyr sequences


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