Accuracy and efficiency define Bxb1 integrase as the best of fifteen candidate serine recombinases for the integration of DNA into the human genome

Zhengyao Xu, Louise Thomas, Ben Davies, Ronald Chalmers, Maggie Smith, William Brown*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)
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Background: Phage-encoded serine integrases, such as phi C31 integrase, are widely used for genome engineering. Fifteen such integrases have been described but their utility for genome engineering has not been compared in uniform assays. Results: We have compared fifteen serine integrases for their utility for DNA manipulations in mammalian cells after first demonstrating that all were functional in E. coli. Chromosomal recombination reporters were used to show that seven integrases were active on chromosomally integrated DNA in human fibroblasts and mouse embryonic stem cells. Five of the remaining eight enzymes were active on extra-chromosomal substrates thereby demonstrating that the ability to mediate extra-chromosomal recombination is no guide to ability to mediate site-specific recombination on integrated DNA. All the integrases that were active on integrated DNA also promoted DNA integration reactions that were not mediated through conservative site-specific recombination or damaged the recombination sites but the extent of these aberrant reactions varied over at least an order of magnitude. Bxb1 integrase yielded approximately two-fold more recombinants and displayed about two fold less damage to the recombination sites than the next best recombinase; phi C31 integrase.

Conclusions: We conclude that the Bxb1 and phi C31 integrases are the reagents of choice for genome engineering in vertebrate cells and that DNA damage repair is a major limitation upon the utility of this class of site-specific recombinase.

Original languageEnglish
Article number87
JournalBMC Biotechnology
Publication statusPublished - 20 Oct 2013

Bibliographical note

This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This work was supported by BBSRC grant: BB/H005277/1; New recombinases for genome engineering.


  • serine recombinases
  • genome manipulation
  • DNA damage
  • site-specific recombination
  • streptomyces phage PHI-BT1
  • PHI-C31 integrase
  • mammalian-cells
  • cassette exchange
  • excision
  • directionality
  • prophage
  • TP901-1
  • system


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