RT Journal
A1 Shang, Renjie
A1 Zhang, Haifeng
A1 Bi, Pengpeng
T1 Generation of mouse conditional knockout alleles in one step using the i-GONAD method
JF Genome Research 
JO Genome Research 
YR 2021 
FD January 01 
VO 31 
IS 1 
SP 121 
OP 130 
DO 10.1101/gr.265439.120 
UL http://genome.cshlp.org/content/31/1/121.abstract 
AB The Cre/loxP system is a powerful tool for gene function study in vivo. Regulated expression of Cre recombinase mediates precise deletion of genetic elements in a spatially– and temporally–controlled manner. Despite the robustness of this system, it requires a great amount of effort to create a conditional knockout model for each individual gene of interest where two loxP sites must be simultaneously inserted in cis. The current undertaking involves labor-intensive embryonic stem (ES) cell–based gene targeting and tedious micromanipulations of mouse embryos. The complexity of this workflow poses formidable technical challenges, thus limiting wider applications of conditional genetics. Here, we report an alternative approach to generate mouse loxP alleles by integrating a unique design of CRISPR donor with the new oviduct electroporation technique i-GONAD. Showing the potential and simplicity of this method, we created floxed alleles for five genes in one attempt with relatively low costs and a minimal equipment setup. In addition to the conditional alleles, constitutive knockout alleles were also obtained as byproducts of these experiments. Therefore, the wider applications of i-GONAD may promote gene function studies using novel murine models.