Figure 5.

TR binds to the intronic TRE of MBD3 gene in the intestine during T3-induced metamorphosis. Premetamorphic tadpoles at stage 54 were treated with (T3) or without T3 (Control) for 2 days. The intestines were dissected out for ChIP assays with a polyclonal antibody against frog TR (anti-TR), RNA polymerase II (anti-Pol), and histone H3 K79m2 (anti-H3K79m2), or negative control IgG (IgG). The immunoprecipitated DNA was analyzed by qPCR for the enrichment of the intronic TRE2 region of the MBD3 gene (MBD3 TRE). Note that strong binding of TR to the MBD3 intronic TRE was observed in the absence of T3 in the premetamorphic tadpoles, and this binding was increased significantly upon T3 treatment. T3 treatment also drastically enhanced the recruit of RNA polymerase II and the level of H3K79 methylation.