The transcriptional coactivators Yap and TAZ are expressed during early Xenopus development

The Yap and TAZ genes encode highly conserved domains which bind various transcription factors. Yap and TAZ act as transcriptional coactivators to modulate transcriptional activity. The activities of Yap and TAZ are negatively regulated by Hippo signaling via direct phosphorylation. In this study, we describe the expression patterns of Yap and TAZ during the development of Xenopus tropicalis. The Xenopus tropicalis Yap (xtYap) and Xenopus tropicalis TAZ (xtTAZ) genes are expressed maternally. xtYap is widely expressed throughout embryogenesis, particularly in the facial connective tissues, branchial arch, midbrain-hindbrain boundary, otic vesicle, pronephros, notochord, hindgut and tailbud. xtTAZexpression occurs predominantly in the presomitic mesoderm, facial connective tissues, brain, branchial arch, trunk neural crest cells and migrating hypaxial myoblasts. In the muscle lineage, xtTAZexpression is transient and restricted to proliferating cells, the presomitic mesoderm and the edges of the hypaxial myoblasts, with no expression detected in mature muscle cells. These results provide insights into the functions of Yap and TAZ and their regulation by Hippo signaling during early development in Xenopus.