The Xenopus eomesodermin promoter and its concentration-dependent response to activin

• Published in: Mechanisms of development 2000-06, Vol.94 (1-2), p.133-146
• Main Authors: Ryan, K, Garrett, N, Bourillot, P, Stennard, F, Gurdon, J B
• Format: Article
• Language: English
• Subjects: Activins; Animals; Base Sequence; Binding Sites; DNA-Binding Proteins - metabolism; Dose-Response Relationship, Drug; Embryo, Nonmammalian; Endoderm - physiology; Forkhead Transcription Factors; Genes, Reporter; Globins - genetics; Globins - metabolism; Inhibins - metabolism; Inhibins - pharmacology; Mesoderm - physiology; Molecular Sequence Data; Promoter Regions, Genetic; Repressor Proteins - genetics; Repressor Proteins - metabolism; Response Elements - drug effects; Response Elements - genetics; Signal Transduction; T-Box Domain Proteins - drug effects; T-Box Domain Proteins - genetics; T-Box Domain Proteins - metabolism; Transcription Factors - metabolism; Xenopus - embryology; Xenopus - genetics; Xenopus Proteins
• ISSN: 0925-4773
• DOI: 10.1016/S0925-4773(00)00300-2

Eomesodermin is an essential early gene in Xenopus mesoderm formation and shows a morphogen-like response to activin. Here we define the regions of the Eomesodermin promoter required for mesodermal expression and for concentration-dependent response to activin. We find an activin response element (ARE) located between -5.6 and -5.0 kb which contains two critical FAST2 binding sites. The ARE alone is necessary and sufficient for concentration-dependent response to activin. A 5.6 kb promoter recapitulates Eomes expression in normal mesoderm cells. A repressor element extinguishes Eomes expression in the endoderm. We relate our results to mesoderm patterning in early Xenopus development and to a mechanism of morphogen gradient response.