Distinct Enhancer Elements Control Hex Expression during Gastrulation and Early Organogenesis
Autor: | James C. Smith, Elena S. Casey, Rosa S. P. Beddington, Richard M. Harland, Tristan A. Rodriguez |
---|---|
Rok vydání: | 2001 |
Předmět: |
medicine.medical_specialty
Mesoderm animal structures Molecular Sequence Data Thyroid Gland Organogenesis Histogenesis Biology Xenopus Proteins node Animals Genetically Modified Embryonic and Fetal Development Mice Species Specificity Internal medicine medicine Animals Tissue Distribution gastrulation Enhancer Molecular Biology Body Patterning Embryonic Induction Homeodomain Proteins AVE Base Sequence integumentary system homeobox Endoderm Gastrula Cell Biology Cell biology Gastrulation medicine.anatomical_structure Endocrinology Enhancer Elements Genetic Gene Expression Regulation Liver Hex embryonic structures Homeobox Endothelium Vascular Definitive endoderm Transcription Factors Developmental Biology |
Zdroj: | Developmental Biology. 234(2):304-316 |
ISSN: | 0012-1606 |
DOI: | 10.1006/dbio.2001.0265 |
Popis: | In the mouse, embryological and genetic studies have indicated that two spatially distinct signalling centres, the anterior visceral endoderm and the node and its derivatives, are required for the correct patterning of the anterior neural ectoderm. The divergent homeobox gene Hex is expressed in the anterior visceral endoderm, in the node (transiently), and in the anterior definitive endoderm. Other sites of Hex expression include the liver and thyroid primordia and the endothelial cell precursors. We have used transgenic analysis to map the cis-acting regulatory elements controlling Hex expression during early mouse development. A 4.2-kb upstream region is important for Hex expression in the endothelial cell precursors, liver, and thyroid, and a 633-bp intronic fragment is both necessary and sufficient for Hex expression in the anterior visceral endoderm and the anterior definitive endoderm. These same regions drive expression in homologous structures in Xenopus laevis, indicating conservation of these regulatory regions in vertebrates. Analysis of the anterior visceral endoderm/anterior definitive endoderm enhancer identifies a repressor region that is required to downregulate Hex expression in the node once the anterior definitive endoderm has formed. This analysis also reveals that the initiation of Hex expression in the anterior visceral endoderm and axial mesendoderm requires common elements, but maintenance of expression is regulated independently in these tissues. |
Databáze: | OpenAIRE |
Externí odkaz: |
načítá se...