Aragón Ferran, Vázquez-Echeverría Citlali, Ulloa Encarna, Reber Michael, Cereghini Silvia, Alsina Berta, Giraldez Fernando, Pujades Cristina
Developmental Biology Group, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
Dev Dyn. 2005 Nov;234(3):567-76. doi: 10.1002/dvdy.20528.
The homeobox-containing gene variant hepatocyte nuclear factor-1 (vHnf1) has recently been shown to be involved in zebrafish caudal hindbrain specification, notably in the activation of MafB and Kro x 20 expression. We have explored this regulatory network in the chick by in ovo electroporation in the neural tube. We show that mis-expression of vHnf1 confers caudal identity to more anterior regions of the hindbrain. Ectopic expression of mvHnf1 leads to ectopic activation of MafB and Kro x 20, and downregulation of Hoxb1 in rhombomere 4. Unexpectedly, mvhnf1 strongly upregulates Fgf3 expression throughout the hindbrain, in both a cell-autonomous and a non-cell-autonomous manner. Blockade of FGF signaling correlates with a selective loss of MafB and Kro x 20 expression, without affecting the expression of vHnf1, Fgf3, or Hoxb1. Based on these observations, we propose that in chick, as in zebrafish, vHnf1 acts with FGF to promote caudal hindbrain identity by activating MafB and Kro x 20 expression. However, our data suggest differences in the vHnf1 downstream cascade in different vertebrates.
含同源异型框的基因变体肝细胞核因子-1（vHnf1）最近被证明参与斑马鱼尾侧后脑的特化，特别是在激活MafB和Kro x 20表达方面。我们通过在神经管内进行鸡胚电穿孔来研究鸡体内的这个调控网络。我们发现，vHnf1的错误表达赋予后脑更靠前区域尾侧特征。mvHnf1的异位表达导致MafB和Kro x 20的异位激活，以及菱脑节4中Hoxb1的下调。出乎意料的是，mvhnf1以细胞自主和非细胞自主的方式在后脑强烈上调Fgf3的表达。FGF信号的阻断与MafB和Kro x 20表达的选择性丧失相关，而不影响vHnf1、Fgf3或Hoxb1的表达。基于这些观察结果，我们提出，在鸡中，与斑马鱼一样，vHnf1与FGF共同作用，通过激活MafB和Kro x 20的表达来促进尾侧后脑特征的形成。然而，我们的数据表明不同脊椎动物中vHnf1下游级联存在差异。
