Hello, I am currently using a Cas9 knock in system that will be expressed in the liver. To do so STOP codon fl/fl Cas9 KI mice were bred with Albumin-Cre mice to generate heterozgous pups, that were then crossed. For future planning, is it reasonable to expand a Cas9 KI+/+ Cre+/+ colony and then breed these animals to a Cas9 KI+/+ Cre-/- mice? Then all pups will be Cas9+/+ Cre-/+. The experiment require a large quantity of male mice.
It is interesting, but you might not be able to identify Cre+/+ (100% sure) mice in a relative reasonable short time. All the best.
Hi Jinbiao,
Can you elaborate as to why I wont be able to identify Cre+/+ mice?
Hi Joselyn,
I note that you intend to cross Cre homs:Cas9KI homs to non-Cre:Cas9KI-homs to generate pups that will all be Cre hets:Cas9KI homs where essentially all mice can be used for experiments.
Theoretically, it should be feasible (if mice are viable and fertile)...however it may not be advisable (see references by JAX and attached article) due to possibility of leaky Cre (in your proposed plan to maintain Cre homs:Cas9KI homs, this may even be bad for the colony if indeed leaky and/or Cre toxicity effects). To be sure, you may need extensive studies, and proper control groups of various genotype combinations to confirm which may not be worth the effort.
Good luck!
References from Jackson Lab:
https://www.jax.org/news-and-insights/jax-blog/2012/november/breeding-strategies-for-tissue-specific-knockout-mice
https://www.jax.org/news-and-insights/jax-blog/2013/september/a-dozen-facts-you-didnt-know-about-cre-lox
Also:
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