Abstract
The type I interferon receptor gene (Ifnar1) encodes a subunit of the heterodimeric receptor complex responsible for mediating type I interferon (IFN-α/β) signaling, a critical pathway in antiviral defense and immune regulation. Ifnar1 knockout (KO) mice are widely used in immunology and virology research to study host-pathogen interactions, immune signaling, and inflammatory processes. Although a conventional Ifnar1 KO model was generated decades ago, advances in genome engineering technologies now allow for more efficient and precise generation of genetically modified animals. We employed CRISPR/Cas9 genome editing to generate a novel Ifnar1 knockout mouse line. Single-guide RNAs targeting the third exon of mouse Ifnar1 gene were electroporated into fertilized C57BL/6J zygotes along with Cas9 protein. The newborn founder mice were screened by PCR and Sanger sequencing to identify mutations at the target site. We successfully established a mouse line harboring a 14-nucleotide deletion in the third exon of Ifnar1. This deletion causes a frameshift mutation, introducing a premature stop codon that is predicted to produce a truncated, non-functional protein. The mutation was confirmed by direct sequencing of the targeted locus. Homozygous mutant mice are viable and fertile. This newly generated Ifnar1 knockout mouse model provides a CRISPR-engineered alternative to the original targeted deletion model described by Müller et al. (1994). The frameshift mutation is expected to ablate IFNAR1 protein function. The model will serve as a valuable resource for immunology and virology research, particularly in studies focused on interferon signaling, antiviral responses, and host-pathogen interactions.