Cre-lox transgenic

[sciencecat]

Cre-lox transgenic

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Post by sciencecat » Wed Apr 13, 2011 1:50 am

I'm studying the cre-lox system and have some questions regarding mouse phenotypes:

Let's say my 'lox' cassette contains a GFP tag, and this cassette properly replaced my gene of interest. So, this means that in whatever cells my gene was expressed, the GFP is now expressed, right?

Now, if I want to make a conditional knockout mouse, I can cross this lox'd mouse to another mouse that contains the Cre 'gene' that is expressed only under a certain, cell-specific promoter.

The progeny of these crossed mice should now be conditional knockouts for my gene of interest in only a specific (Cre-targeted) cell subset.

My question is: if the lox'd mouse is already a knockout, then how does crossing to the Cre-mouse induce a conditional knockout? I understand how the cre-lox system works theoretically, but I don't understand how the lox'd mouse will give you a conditional knockout if my gene of interest has already been replaced with the lox'd cassette.

Any comments would be much appreciated!

[sciencecat]

Re: Cre-lox transgenic

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Post by sciencecat » Wed Apr 13, 2011 2:11 am

I forgot the most important thing! The lox'd cassette requires your gene sequence to be present. So, my GFP reporter will tell me the cassette has been homologously recombined with the original gene sequence, but my gene of interest will still be expressed. I think it's beginning to make sense...

[JackBean]

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Post by JackBean » Wed Apr 13, 2011 5:41 am

I think that the first cassette contains both the gene of interest and GFP, thus later you can cut it off