T promoter activity in the absence of functional T protein during axis formation and elongation in the mouse.
The T (Brachyury) gene, which encodes a transcription factor, is involved in the formation of posterior mesoderm. Although studies in Xenopus have shown that T gene expression is responsive to mesoderm inducing factors and furthermore suggest the existence of an autoregulatory loop involving T itself, eFGF, and the FGF receptor, little is known about the regulation of T expression in the mouse. We report here that in the mouse the expression of fgf-4, the putative homologue of Xenopus efgf, is not dependent on the presence of T protein during the first 48 hr of gastrulation. Furthermore, we address the question of autoregulation using a chimeric approach. Introduction of a T promoter-lacZ construct into T/T ES cells results in T promoter activity in the primitive streak and tail bud in the absence of functional T protein. Therefore, we suggest that a direct FGF and T autoregulatory loop is unlikely to operate during gastrulation and axis elongation in the mouse.
Schmidt
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C
National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom.
Wilson
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V
Stott
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Beddington
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RS
D000818:Animals; D002460:Cell Line; D002678:Chimera / Q000235:genetics / Q000502:physiology; D002999:Clone Cells; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000235:genetics* / Q000502:physiology; D005326:Fetal Proteins / Q000235:genetics* / Q000502:physiology; D051519:Fibroblast Growth Factor 4; D005346:Fibroblast Growth Factors / Q000235:genetics; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007763:Lac Operon; D008648:Mesoderm / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics; D020825:T-Box Domain Proteins; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D000098908:Brachyury Protein
D004268:DNA-Binding Proteins; D005326:Fetal Proteins; D051519:Fibroblast Growth Factor 4; D005346:Fibroblast Growth Factors; D011518:Proto-Oncogene Proteins; D020825:T-Box Domain Proteins; D014157:Transcription Factors; D000098908:Brachyury Protein; C496446:Fgf4 protein, mouse