Positive and negative regulation of the transforming growth factor β/activin target gene goosecoid by the TFII-I family of transcription factors

Goosecoid (Gsc) is a homeodomain-containing transcription factor present in a wide variety of vertebrate species and known to regulate formation and patterning of embryos. Here we show that in embryonic carcinoma P19 cells, the transcription factor TFII-I forms a complex with Smad2 upon transforming growth factor beta (TGF beta)/activin stimulation, is recruited to the distal element (DE) of the Gsc promoter, and activates Gsc transcription. Downregulation of endogenous TFII-I by small inhibitory RNA in P19 cells abolishes the TGF beta-mediated induction of Gsc. Similarly, Xenopus embryos with endogenous TFII-I expression downregulated by injection of TFII-I-specitic antisense oligonucleotides exhibit decreased Gsc expression. Unlike TFII-I, the related factor BEN (binding factor for early enhancer) is constitutively recruited to the distal element in the absence of TGF beta/activin signaling and is replaced by the TFII-I/Smad2 complex upon TGF beta/activin stimulation. Overexpression of BEN in P19 cells represses the TGF beta-mediated transcriptional activation of Gsc. These results suggest a model in which TFII-I family proteins have opposing effects in the regulation of the Gsc gene in response to a TGF beta/activin