Figure 1.

Treatment with T₃-induced time-dependent increases in immunoreactivity for the DNA demethylation intermediates 5-hmC and 5-caC, and the methylcytosine dioxygenase TET3 in premetamorphic tadpole brain. We treated premetamorphic (NF stage 50) X. tropicalis tadpoles with vehicle (Veh; 0.0003% DMSO) for 24 hours, or T₃ (50 nM) for 24 or 48 hours (hr) added to the aquarium water before collecting and fixing brains for immunohistochemistry for 5-hmC, 5-caC, and TET3. A: Shown are representative micrographs of the region of the tadpole brain containing the thalamic nuclei and ventral hypothalamus (section K in Supplemental Fig. 1; abbreviations are defined in Supplemental Table 1) (62) stained with DAPI or with antibodies to the three different antigens, captured at 10x magnification. Scale bar = 0.5 mm. B: Densitometric analysis of 5-hmC, 5-caC, and TET3 immunoreactivity in tadpole brain after treatment with T₃. Bars represent the mean ± SEM (n = 5–6/time point). Means with the same letter are not significantly different (one-way ANOVA; P < 0.05; Fisher’s LSD).