TCF is the nuclear effector of the beta-catenin signal that patterns the sea urchin animal-vegetal axis.
TCF is the nuclear effector of the beta-catenin signal that patterns the sea urchin animal-vegetal axis.
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TCF 是 β-连环蛋白信号的核效应器，该信号形成海胆动植物轴。
DOI：
10.1006/dbio.1999.9551
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发表时间：
2000
影响因子：
2.7
通讯作者：
Venuti,JM
中科院分区：
文献类型：
--
作者：
Vonica,A;Weng,W;Gumbiner,BM;Venuti,JM
海胆胚胎中动物-植物（AV）轴形成的机制还不完全清楚。轴的规范被认为涉及细胞间信号和尚未确定的母体决定因素的组合。在非洲爪蟾中，Wnt通路在定义胚胎轴中起着至关重要的作用。最近在海胆中的实验表明，Wnt信号通路的至少两种组分，GSK 3 β和β-连环蛋白，参与胚胎AV轴模式。这些结果支持的概念，发展网络，调节轴向图案在后口动物是进化保守的。为了进一步验证这一假设，我们研究了β-连环蛋白核结合伴侣（转录调节因子TCF家族成员）在海胆AV轴模式中的作用。为了测试TCF在海胆AV轴发育中介导β-连环蛋白信号的作用，我们研究了显微注射编码改变形式的TCF的RNA对海胆发育的影响。我们表明，显性阴性TCF的表达导致经典的“动物化”胚胎。相比之下，显微注射编码激活的TCF的RNA产生高度“植物化”的胚胎。我们发现，内源性海胆TCF的反式激活活性被LiCl处理增强，其通过抑制GSK 3使胚胎植物化，这与内源性β-连环蛋白和TCF之间的体内相互作用一致。我们还提供了证据表明，所有β-连环蛋白的活动模式的海胆AV轴是由TCF介导的。使用糖皮质激素反应的TCF，我们表明，TCF转录活性影响规范沿着AV轴之间的受精和60细胞阶段。
The mechanism of animal–vegetal (AV) axis formation in the sea urchin embryo is incompletely understood. Specification of the axis is thought to involve a combination of cell–cell signals and as yet unidentified maternal determinants. In Xenopus the Wnt pathway plays a crucial role in defining the embryonic axes. Recent experiments in sea urchins have shown that at least two components of the Wnt signaling pathway, GSK3β and β-catenin, are involved in embryonic AV axis patterning. These results support the notion that the developmental network that regulates axial patterning in deuterostomes is evolutionarily conserved. To further test this hypothesis, we have examined the role of β-catenin nuclear binding partners, members of the TCF family of transcriptional regulators, in sea urchin AV axis patterning. To test the role of TCFs in mediating β-catenin signals in sea urchin AV axis development we examined the consequences of microinjecting RNAs encoding altered forms of TCF on sea urchin development. We show that expression of a dominant negative TCF results in a classic “animalized” embryo. In contrast, microinjected RNA encoding an activated TCF produces a highly “vegetalized” embryo. We show that the transactivational activity of endogenous sea urchin TCF is potentiated by LiCl treatment, which vegetalizes embryos by inhibiting GSK3, consistent with an in vivo interaction between endogenous β-catenin and TCF. We also provide evidence indicating that all of β-catenin's activity in patterning the sea urchin AV axis is mediated by TCF. Using a glucocorticoid-responsive TCF, we show that TCF transcriptional activity affects specification along the AV axis between fertilization and the 60-cell stage.