Fig. 4. Phox2b and Th expression in thoracic paravertebral sympathetic ganglia is suppressed in E18.5 Gata3 mutant embryos. (A-C) Whole-mount X-gal staining of E18.5 Gata3^Z/+ and Gata3^Z/- embryos with and without Tg^hDBH-G3 transgene. ß-Gal⁺ sympathetic chain was shrunken in the pharmacologically rescued Gata3^Z/- embryos. (D,F) The size of sympathetic ganglion is reduced in the pharmacologically rescued Gata3^-/- embryos in HE sections. In Gata3^Z/-:Tg^hDBH-G3 embryos, anti-Phox2b and anti-Th staining and sympathetic ganglion size were restored (B,E,H,K); the control animals used were Gata3^Z/+ (A) and Gata3^+/+ (WT; wild-type) littermates (D,G,J). Broken lines indicate outer margins of sympathetic ganglia. (I,L) In Gata3^-/- embryos, Phox2b and Th expression was significantly reduced in thoracic paravertebral sympathetic ganglia. Scale bar: 100 µm. (M,N) At least four serial sections of each of the four examined ganglia from two different embryos of each genotype were evaluated. Phox2b- and Th-expressing cells (M) and the total surface areas (N) of the thoracic paravertebral sympathetic ganglia in control and Gata3 mutant embryos with and without Tg^hDBH-G3 were quantified and represented as histogram. Data are presented as the mean±s.e.m. The statistical significance of the differences between Gata3^-/-:Tg^hDBH-G3 and Gata3^-/- are indicated (^*P<0.05; ^**P<0.01; Student's t-test).