Gene targeting strategy for B-hFCER1A mice. The exons 1-5 of mouse Fcer1a gene that encode the extracellular domain were replaced by human FCER1A exons 3-7 in B-hFCER1A mice.

Strain specific FCER1A expression analysis in homozygous B-hFCER1A mice by flow cytometry. Basophilic granulocytes of the bone marrow were collected from wild type (WT) mice (+/+) and homozygous B-hFCER1A mice (H/H), and analyzed by flow cytometry with species-specific anti-FCER1A antibody. Mouse FCER1A was detectable in WT mice (+/+). Human FCER1A was exclusively detectable in homozygous B-hFCER1A mice (H/H) but not in WT mice (+/+).