Ifnb1 Conditional Knockout mouse models

Unlike the multigene alpha cluster, Ifnb1 is single copy, which makes this mouse ortholog of human IFNB1 the rate limiting first wave ligand of the type I interferon system. Transcription is driven by IRF3 dimers phosphorylated at Ser386 and Ser396 by TBK1 downstream of cGAS and STING, MAVS, or TRIF, cooperating with NF-kB and ATF2 with c-Jun on the compact enhanceosome, and the resulting autocrine IFNAR signal induces IRF7 to amplify the alpha subtypes. That architecture means a conditional Ifnb1 null truncates the initiating signal without touching amplification, a knockin reporter such as luciferase times and localizes sensing in vivo, and Ifnar1 deletion instead removes all downstream response. Because human IFNB1 does not productively engage murine IFNAR, humanization is required for biologic pharmacology. Cell type assignment matters more here than for most cytokines, since stromal, dendritic, and epithelial sources differ, so pair the flox with lineage restricted Cre drivers.

Ifnb1 conditional knockout mice carry a floxed allele so you delete function only where Cre is active. The germline allele stays intact until you cross to a tissue specific Cre. Labs reach for this design when a global knockout is lethal, when they need adult onset loss, or when regional redundancy hides a whole body phenotype.