Accelerate your research with customized gene knockout mouse models that provide thorough insight into key genetic mechanisms.
Uncover genetic functions and explore cellular processes
Develop in-depth understanding of pathogenesis and the prevention of disease
Simplify the evaluation of compounds in drug discovery
Gene knockout mouse models include:：
Shanghai Model Organisms Center (SMOC) has more than 900 research-ready GEM models and one of them may contain the gene that you are interested in.
Alternatively, you may contact our technical consultants to design and customize your own gene knockout mouse model.
Conventional (Constitutive) Gene Knockout
Generate a conventional (constitutive) gene knockout (KO) mouse model to permanently inactivate your target gene.
It usually takes 4-6 months to generate a conventional (constitutive) gene knockout mouse model by CRISPR gene editing technology.
Pre-designed synthetic sgRNAs and Cas9 mRNA are co-injected into mouse fertilized eggs. sgRNAs targeting specific loci in the genome will guide Cas9 enzyme to the locus and Cas9 nuclease will cut the target site. Non-homologous end joining (NHEJ) repair of this cut will cause coding sequence frameshift mutation via small insertions and deletions (indels) which results in gene(s) knockout. NHEJ repair is a random process and different repairs may result in different cells of the same mouse. F0 mice should be bred to obtain stably inherited gene knockout heterozygote mice.
It usually takes 7-12 months to generate a conventional (constitutive) gene knockout mouse model by ES cell targeting technology.
A homologous recombination vector in which one or more exons of the target gene were replaced with a neomycin (Neo) gene was generated and transformed into ESC clones to obtain an ES clone in which homologous recombination occurred correctly. The targeted ES cells were injected into blastocysts injection to obtain a partial ES-derived chimeric mouse. The the chimeric mouse was mated with the wild type mice to finally obtain a heterozygous mouse derived from the recombinant ES cell. Specific exon(s) of target gene on one chromosome of heterozygous mice have been replaced by a Neo gene, and then homozygous mice with inactivated target gene were obtained by mating between heterozygous mice.
Conditional Gene Knockout
Conditional knockout (CKO) can be used to knock out a target gene of interest in temporal-specific or spatial-specific pattern, enabling more accurate gene knockout and more forcused research.
Conditional gene knockout is mainly achieved by site-specific recombinase systems such as Cre-LoxP, FLP-Frt and Dre-Rox. Amongst which, the Cre-LoxP system is the most frequently used method, whereby a LoxP sequence is placed at each end of a DNA sequence to be knocked out to generate a Flox (flanked by LoxP) mouse. Flox mice are crossed with Cre-expressing mice to obtain a mouse with tissue- or cell-specific knockout target gene.
Such Flox mice avoid embryonic or neonatal lethality that may occur in constitutive knockout mice. By crossing with different Cre-expressing mice to generate offspring which can direct the expression or deletion of the target gene at any developmental stage or any specific cell type of the experimental animal. Moreover, when combined with other inducible Cre systems, target gene can be temporally and spatially regulated simultaneously. The most widely used application is the Cre/ERT system.
It usually takes 6-9 months to generate a conditional gene knockout mouse model by CRISPR gene editing technology.
It usually takes 9-12 months to generate a conditional gene knock-in mouse model by ES cell targeting technology.
KO first (Conditional Ready) is a multipurpose model which is similar to the conditional knockout where LoxP sites with the same orientation flank the target fragment and the SA-IRES-reporter fragment flanked by FRT sites is placed within the 5' end intron. This type of mouse model has two main applications:
1) Mating with Cre-expressing mice results in the deletion of Neo gene and Flox region to generate reporter genes and knockout mice. As the reporter gene is expressed by the promoter of the target gene, expression of the target gene can be tracked by monitoring the expression levels of the reporter gene.
2) Mating with Flp-expressing mice results in the deletion of SA-IRES-reporter fragment to obtain conventional Flox mice. Flox mice are then mated with various tissue-specific Cre-expressing mice to obtain a range of conditional knockout models.