FIG. 1.

Induction of endoderm and thyroid transcriptional factors by Activin A. Induction of endodermal cells by Activin A leads to the upregulation of endodermal markers and also a basal increase in thyroid-specific transcription factors. Representative quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis for (A) endoderm markers SOX17 and FOXA2 and (B) thyroid transcriptional factors PAX8, NKX2-1, FOXE1, and HEX on Activin A–treated and control (untreated) cells. Data are expressed as mean ± standard error of the mean (SEM), and represent one of three separate experiments. Statistical analysis by unpaired two-tailed Student's t-test gave *p < 0.0001 for each gene in the Activin A–treated cells compared with the untreated controls.