Tead proteins activate the Foxa2 enhancer in the node in cooperation with a second factor.

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Cellular development involves dynamic changes in cell populations and organizer activity.
• The Foxa2 gene plays a critical role in mouse node and notochord development.
• Understanding the regulatory mechanisms of gene enhancers is key to deciphering developmental processes.

Purpose of the Study:

• To investigate the mechanism of mouse node development by analyzing the Foxa2 gene's node/notochord enhancer (NE).
• To identify the specific DNA motifs and transcription factors involved in regulating the NE.
• To determine the functional significance of these regulatory elements in vivo.

Main Methods:

• Identification of the core element (CE) of the Foxa2 NE.
• Activation assays in P19 cells treated with Wnt/beta-catenin.
• Analysis of sequence motifs within the CE.
• ChIP assays to identify transcription factor binding.
• Functional studies in transgenic mouse and zebrafish embryos.

Main Results:

• A multimeric CE drives gene expression in the node, activated by Wnt/beta-catenin with a time lag.
• Two distinct sequence motifs within the CE are essential for enhancer activity in vitro and in vivo.
• Tead family transcription factors and YAP65 bind to the 3' motif and activate the CE.
• Inhibition of Tead activity impairs NE enhancer function and notochord development in mice.
• Tead manipulation in zebrafish alters foxa2 expression in the embryonic shield.

Conclusions:

• Tead transcription factors, in conjunction with a 5' element-binding factor, activate the Foxa2 enhancer core element in the mouse node.
• A similar Tead-mediated regulatory mechanism is involved in zebrafish embryonic shield development.
• This study elucidates a conserved molecular mechanism controlling early vertebrate development.