Schmidt C, Wilson V, Stott D, Beddington R S
National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom.
Dev Biol. 1997 Sep 15;189(2):161-73. doi: 10.1006/dbio.1997.8661.
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.
T（短尾蛋白）基因编码一种转录因子，参与后中胚层的形成。虽然在非洲爪蟾中的研究表明，T基因表达对中胚层诱导因子有反应，并且进一步提示存在一个涉及T自身、表皮生长因子（eFGF）和成纤维细胞生长因子（FGF）受体的自调节环，但对于小鼠中T表达的调控知之甚少。我们在此报告，在小鼠中，非洲爪蟾表皮生长因子（efgf）的假定同源物成纤维细胞生长因子4（fgf-4）的表达在原肠胚形成的最初48小时内不依赖于T蛋白的存在。此外，我们使用嵌合方法探讨了自调节问题。将T启动子-乳糖操纵子（lacZ）构建体导入T/T胚胎干细胞（ES细胞），在没有功能性T蛋白的情况下，会在原条和尾芽中产生T启动子活性。因此，我们认为在小鼠原肠胚形成和轴伸长过程中，直接的FGF和T自调节环不太可能起作用。
