Cre-lox etc...

John Dixon jpcd0 at
Wed Oct 4 11:50:54 EST 1995

In article <44rdqt$mc8 at>, Przemko <przemko> wrote:

> Hi!
> I am about to knock some genes and I will use (or try to) Cre-lox system. I
> have done some reading etc. but I have a few questions that I hope someone
> could help me with:
> -what is the min and max distance between the lox sites for Cre to work
> efficiently?

In mechanism of Strand cleavage and exchange in the cre-lox site specific
recombination system, Hoess and Abremski J Mol Biol 1985, 181 351-362, a
186 bp fragment is recombined out.

'A site directed chromosomal translocation induced in embryonic stem cells
by Cre loxP recombination' Smith et al Nature Genetics vol 9 April 1995
p376on, has useful refs incl one showing recombination of 6kb apart as
well as demonstrating
interchromosomal recombination

> -how about efficiency in nondividing cells, since you presumably need at least
> mitotic division for a recombination to take place?
> -in one of the constructs by Sauer there is a transcriptional STOP cassette
> used, any reasons for the SV40 polyA signal?
> -what are the biggest, PRACTICAL, limitations of that procedure (like criptic
> lox sites in the chromosomes etc.)

Check out 'Identification of Cryptic lox sites in the yeast genome...' B
Sauer J Mol Biol 1992 223 911-928

> Thank you all for your answers. You might be better off to mail it to me,
> instead of posting. I WILL summarize and post replies.
> ThanX again
> Przemko

Hope these are some use

Good luck

P.S. Your email address bounces


John Dixon                                        Lab 44 (1223) 334131
Wellcome/CRC Institute                            Fax 44 (1223) 334134
Department of Genetics
Cambridge University    
United Kingdom                           e-m: jpcd0 at

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