Fig. 5.

TRβ knockout reduces TR binding to the TRE region in the tadpole intestine after T3 treatment. Five or more age-matched wild type and TRβ knockout tadpoles at stage 54 were kept in 4-l plastic container and treated with or without 10 nM T3 for 18 h. The chromatin of the intestine was isolated and immunoprecipitated with antibodies against TR and ID14 as a negative control. The immunoprecipitated DNA was analyzed by real-time PCR for the presence of the TRE region or the exon 5, which lacks any TRE, of the TRβ gene. Note that TR binding to the TRE region was significantly reduced in the intestine of TRβ knockout tadpoles. Two asterisks (**) indicate statistically significant differences (P < 0.01)