A Wnt-FoxQ2-Nodal Pathway Links Primary and Secondary Axis Specification in Sea Urchin Embryos

• Published in: Developmental cell 2008-01, Vol.14 (1), p.97-107
• Main Authors: Yaguchi, Shunsuke, Yaguchi, Junko, Angerer, Robert C., Angerer, Lynne M.
• Format: Article
• Language: English
• Subjects: Animals; beta Catenin - physiology; Biological and medical sciences; Body Patterning - physiology; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; DEVBIO; Ectoderm - growth & development; Ectoderm - physiology; Embryo, Nonmammalian - physiology; Embryonic Development - physiology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental; Molecular and cellular biology; RNA, Messenger - genetics; Sea Urchins - embryology; Transcription Factors - genetics; Transcription Factors - physiology; Wnt Proteins - genetics; Wnt Proteins - physiology
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2007.10.012

The primary (animal-vegetal) (AV) and secondary (oral-aboral) (OA) axes of sea urchin embryos are established by distinct regulatory pathways. However, because experimental perturbations of AV patterning also invariably disrupt OA patterning and radialize the embryo, these two axes must be mechanistically linked. Here we show that FoxQ2, which is progressively restricted to the animal plate during cleavage stages, provides this linkage. When AV patterning is prevented by blocking the nuclear function of β-catenin, the animal plate where FoxQ2 is expressed expands throughout the future ectoderm, and expression of nodal, which initiates OA polarity, is blocked. Surprisingly, nodal transcription and OA differentiation are rescued simply by inhibiting FoxQ2 translation. Therefore, restriction of FoxQ2 to the animal plate is a crucial element of canonical Wnt signaling that coordinates patterning along the AV axis with the initiation of OA specification.