Figure 2.
Inner ear-specific knockout of Gata3 in mice. (A) Schematic diagram showing Gata3 genomic structure, restriction map, and the strategy for generating Gata3loxp mice. Black box represents Exon 4 coding sequences. Thick bars are the sequences used to generate the homologous arms in the targeting vector. The targeting vector is designed to insert loxP sites (white arrowheads) on either side of Exon 4, which encoding the first zinc-finger motif. The neomycin resistance cassette (Neo, for positive selection) is flanked by FRT sites (black arrowheads) and can be removed through crossing to FLPe-expressing mice. DTA (diphtheria toxin gene) is included for negative selection. (B) PCR analysis of the wild-type, heterozygous, and homozygous Gata3 conditional knockout mice. (C–F) Immunolabeling analysis shows that Gata3 is efficiently deleted in the otocyst of Gata3-null mice. In wild-type mice, GATA3 is highly expressed in the nuclei of otic epithelial cells (C and D). However, the specific nuclear expression of GATA3 is ablated in the Gata3-null otocyst (E and F). OV, otic vesicle. D, dorsal; M, medial. Scale bar, 20 µm.