Department of Neurobiology, University of Chicago, Chicago, Illinois 60637, USA.
Genes Dev. 2011 Sep 1;25(17):1759-62. doi: 10.1101/gad.17594311.
In canonical Wnt signaling, β-catenin translocates to the cell nucleus, interacting with Tcf/Lef factors to activate transcription of Wnt target genes. In this issue of Genes & Development, Vacik and colleagues (pp. 1783-1795) report that a highly conserved sequence in intron 5 of Tcf7l2 conceals an internal promoter region that, when activated by Vax2, drives transcription of truncated Tcf7l2 mRNAs. The encoded Tcf7l2 protein binds to DNA, but not β-catenin, and therefore acts as a dominant-negative Wnt antagonist.
在经典的 Wnt 信号通路中，β-连环蛋白易位到细胞核内，与 Tcf/Lef 因子相互作用，激活 Wnt 靶基因的转录。在本期《基因与发育》杂志中，Vacik 及其同事（第 1783-1795 页）报道称，Tcf7l2 内含子 5 中的一个高度保守序列隐藏了一个内部启动子区域，当该区域被 Vax2 激活时，会驱动截断的 Tcf7l2 mRNA 的转录。编码的 Tcf7l2 蛋白与 DNA 结合，但不与 β-连环蛋白结合，因此作为一种显性负性的 Wnt 拮抗剂发挥作用。
