Figure 1.

Targeted expression of human Siglec-8 into mouse mast cells. Schematic overview of the generation of conditional knock-in mice that express human Siglec-8 on mast cells. A ROSA26-DEST vector-based targeting construct was generated that contains the CAG promoter, LoxP-floxed-Neo/Kan as a STOP fragment followed by human Siglec-8 cDNA. Using standard procedures, ROSA26-CAG-STOP-Siglec-8 (or simply ROSA26-Siglec-8) knock-in mice were generated. After cross-breeding to mast cell specific Cre mouse lines (CPA3-Cre and Mcpt5-Cre), Cre-mediated removal of the conditional Neo-STOP fragment led to CAG promoter driven human Siglec-8 expression on mast cells. Terms used are CAG: CAG promoter (a combined fusion of CMV enhancer, chicken beta-Actin promoter and rabbit beta-Globin splice acceptor site); Neo/Kan: Neomycin/Kanamycin resistant gene; LoxP: LoxP recognition sequences.