Control of somitic expression of tenascin in Xenopus embryos by myogenic factors and Brachyury

• Published in: Developmental dynamics 1994-08, Vol.200 (4), p.269-277
• Main Authors: Umbhauer, M., Riou, J.‐F., Smith, J. C., Boucaut, J. C.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cell Adhesion Molecules, Neuronal - genetics; Cell Adhesion Molecules, Neuronal - metabolism; DNA-Binding Proteins - metabolism; DNA-Binding Proteins - physiology; Embryo, Nonmammalian - metabolism; Embryology: invertebrates and vertebrates. Teratology; Embryonic and Fetal Development; Extracellular Matrix Proteins - genetics; Extracellular Matrix Proteins - metabolism; Fetal Proteins - metabolism; Fetal Proteins - physiology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Mesoderm - metabolism; Muscle Proteins - metabolism; Muscles - embryology; MyoD Protein - metabolism; Myogenic Regulatory Factor 5; Nerve Tissue Proteins - metabolism; Organogenesis. Fetal development; Organogenesis. Physiological fonctions; RNA, Messenger - metabolism; Somitic mesoderm; T-Box Domain Proteins; Tenascin; Tissue Distribution; Trans-Activators; XBra; Xenopus laevis - embryology; Xenopus Proteins; XMyf5; XMyoD
• ISSN: 1058-8388; 1097-0177
• DOI: 10.1002/aja.1002000402

Tenascin is a large glycoprotein which is expressed in a restricted pattern in the extracellular matrix (ECM) of vertebrate embryos. Tenascin interferes with cell‐fibronectin interactions in vitro, and may play a role in the control of cell migration and differentiation during development. In Xenopus, tenascin immunoreactivity is first detected at the early tailbud stage in the ECM of the most anterior somite. Thereafter, it is distributed dorsally along neural crest cell migration pathways. In this paper, we report that tenascin mRNA is most abundant in dorsal mesoderm at the neurula stage and in somites at the early tailbud stage, indicating that the initial accumulation of tenascin in the ECM is due to secretion from paraxial mesoderm. To understand how tenascin expression in somitic mesoderm is controlled, we have expressed Xbra and the myogenic factors XMyoD and XMyf5 in blastula animal cap tissue. The tenascin gene is activated by all three transcription factors. Interestingly, expression of tenascin mRNA, and accumulation of the protein in the ECM, can occur without formation of muscle. Our results suggest that tenascin regionalization in early Xenopus embryos depends on tenascin RNA expression by somitic mesoderm, where it is likely to be activated by myogenic factors. © 1994 Wiley‐Liss, Inc.