Factors required in vitro for excision of the Bacteroides conjugative transposon, CTnDOT

Yuri Sutanto, Jeanne M. DiChiara, Nadja B. Shoemaker, Jeffrey F. Gardner, Abigail A. Salyers

Research output: Contribution to journalArticlepeer-review


Four genes have been found to be essential for excision of the Bacteroides conjugative transposon CTnDOT in vivo: intDOT, orf2c, orf2d, and exc. The intDOT gene encodes an integrase that is essential for integration and excision. The function of the other genes is still uncertain. Previously, we developed an in vitro system for the integration reaction. We have now developed an in vitro system for excision. In this system, the left and right junctions of CTnDOT, attL, and attR, are provided on separate plasmids. The excision reaction produced a cointegrate which contained the attDOT (the joined ends of CTnDOT) and attB (the chromosomal target site). Cointegrate formation was observed after electroporation of Escherichia coli with the assay mixture and was also detected directly in the assay mixture by Southern hybridization. The highest reaction frequencies (10 -3) were obtained with a mixture that contained purified IntDOT and a cell extract from Bacteroides thetaiotaomicron 4001, which contained the excision region of CTnDOT carried on a plasmid. An unexpected finding was that the addition of purified Exc, which is essential for excision in vivo, was not required for excision in vitro, nor did it increase the frequency of cointegrate formation.

Original languageEnglish (US)
Pages (from-to)119-130
Number of pages12
Issue number2
StatePublished - Sep 2004


  • Bacteroides resistance gene transfer elements
  • CTnDOT
  • Excision factors
  • Host factors
  • In vitro excision system

ASJC Scopus subject areas

  • Molecular Biology


Dive into the research topics of 'Factors required in vitro for excision of the Bacteroides conjugative transposon, CTnDOT'. Together they form a unique fingerprint.

Cite this