The Coral Symbiomics Lab
Red Sea Research Center
Division of Biological and Environmental Science and Engineering

Publications in 2001

Altered directionality in the cre-loxP site-specific recombination pathway11Edited by M. Yaniv

​Aranda, Kanellopoulou, Christ, Peitz, Rajewsky and Dröge, “Altered directionality in the cre-loxP site-specific recombination pathway11Edited by M. Yaniv,” Journal of Molecular Biology 311, no. 3 (2001).
Manuel Aranda, Chryssa Kanellopoulou, Nicole Christ, Michael Peitz, Klaus Rajewsky, Peter Dröge
Cre, site alignment, site-specific recombination, strand exchange, synaptic complex
The site-specific recombinase Cre must employ control mechanisms to impose directionality on recombination. When two recombination sites (locus of crossing over in phage P1, loxP) are placed as direct repeats on the same DNA molecule, collision between loxP-bound Cre dimers leads to excision of intervening DNA. If two sites are placed as inverted repeats, the intervening segment is flipped around. Cre catalyzes these reactions in the absence of protein co-factors. Current models suggest that directionality is controlled at two steps in the recombination pathway: the juxtaposition of loxP sites and the single-strand-transfer reactions within the synaptic complex. Here, we show that in Escherichia coli strain 294-Cre, directionality for recombination is altered when the expression of Cre is increased. This leads to deletion instead of inversion on substrates carrying two loxP sites as inverted repeats. The nucleotide sequence composition of loxP sites remaining in aberrant products indicates that site alignment and/or DNA strand transfer in the in vivo Cre-loxPrecombination pathway are not always tightly controlled.