Nuclear factor 1 and T-cell factor/LEF recognition elements regulate Pitx2 transcription in pituitary development.
Pitx2, a paired-related homeobox gene that is mutated in Rieger syndrome I, is the earliest known marker of oral ectoderm. Pitx2 was previously shown to be required for tooth, palate, and pituitary development in mice; however, the mechanisms regulating Pitx2 transcription in the oral ectoderm are poorly understood. Here we used an in vivo transgenic approach to investigate the mechanisms regulating Pitx2 transcription. We identified a 7-kb fragment that directs LacZ expression in oral ectoderm and in many of its derivatives. Deletion analysis of transgenic embryos reduced this fragment to a 520-bp region that directed LacZ activity to Rathke's pouch. A comparison of the mouse and human sequences revealed a conserved nuclear factor 1 (NF-1) recognition element near a consensus T-cell factor (TCF)/LEF binding site. The mutation of either site individually abolished LacZ activity in transgenic embryos, identifying Pitx2 as a direct target of Wnt signaling in pituitary development. These findings uncover a requirement for NF-1 and TCF factors in Pitx2 transcriptional regulation in the pituitary and provide insight into the mechanisms controlling region-specific transcription in the oral ectoderm and its derivatives.
Ai
Di
D
Institute of Biosciences and Technology, Texas A&M System Health Science Center, Houston, TX 77030, USA.
Wang
Jun
J
Amen
Melanie
M
Lu
Mei-Fang
MF
Amendt
Brad A
BA
Martin
James F
JF
D024509:3' Flanking Region / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004475:Ectoderm / Q000166:cytology / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009055:Mouth / Q000196:embryology; D009154:Mutation / Q000235:genetics; D051839:NFI Transcription Factors / Q000378:metabolism*; D010902:Pituitary Gland / Q000196:embryology*; D011485:Protein Binding; D051820:TCF Transcription Factors / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D000097577:Homeobox Protein PITX2
D018398:Homeodomain Proteins; D051839:NFI Transcription Factors; D051820:TCF Transcription Factors; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2