Dorsal-ventral patterning: Crescent is a dorsally secreted Frizzled-related protein that competitively inhibits Tolloid proteases.
Dorsal-ventral patterning: Crescent is a dorsally secreted Frizzled-related protein that competitively inhibits Tolloid proteases.
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背腹模式：Crescent 是一种背侧分泌的卷曲相关蛋白，可竞争性抑制 Tolloid 蛋白酶。
DOI：
10.1016/j.ydbio.2011.01.029
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发表时间：
2011
影响因子：
2.7
通讯作者：
DeRobertis,EdwardM
中科院分区：
文献类型：
--
作者：
Ploper,Diego;Lee,HojoonX;DeRobertis,EdwardM
在爪蟾中，背腹（D-V）模式可以在胚胎二等分后自我调节。这是由原肠胚背侧和腹侧中心分泌的细胞外蛋白质网络介导的。具有相似活性的不同蛋白质可以在这两个极点分泌，但受到相反的转录控制。在这里，我们表明 Crescent（一种背侧蛋白）可以补偿 Sizzled（一种腹侧蛋白）的损失。 Crescent 是一种分泌型卷曲相关蛋白 (sFRP)，已知可调节 Wnt8 和 Wnt11 活性。我们现在发现 Crescent 也调节 BMP 通路。 BMP 拮抗剂 Chordin 增加 Crescent 表达，BMP4 抑制 Crescent 表达，而 Sizzled 则相反。 Crescent 敲低增加了 BMP 靶基因的表达，并与 Sizzled morpholinos 产生协同作用。因此，Crescent 的功能丧失可以通过增加其腹侧对应物 Sizzled 的表达来补偿。 Crescent 过度表达使整个胚胎背侧化，但不是腹侧半胚胎，这表明 Crescent 需要背侧成分才能发挥其抗 BMP 活性。新月蛋白在缺乏脊索蛋白的胚胎中失去了其背侧活性。当共同注射时，新月蛋白和脊索蛋白在非洲爪蟾胚胎的背侧化中具有极大的协同作用。这些表型的分子机制可以通过 Crescent 抑制 Tolloid 金属蛋白酶的能力来解释，而 Tolloid 金属蛋白酶通常会降解 Chordin。酶动力学研究表明 Crescent 是 Tolloid 活性的竞争性抑制剂，它与 Tolloid/BMP1 结合的 KD 为 11 nM。总之，Crescent 是 D–V 通路的一个新组成部分，通过调节 Tolloid 家族的脊索酶，充当 Sizzled 的背侧对应物。
In Xenopus, dorsal–ventral (D–V) patterning can self-regulate after embryo bisection. This is mediated by an extracellular network of proteins secreted by the dorsal and ventral centers of the gastrula. Different proteins of similar activity can be secreted at these two poles, but under opposite transcriptional control. Here we show that Crescent, a dorsal protein, can compensate for the loss of Sizzled, a ventral protein. Crescent is a secreted Frizzled-Related Protein (sFRP) known to regulate Wnt8 and Wnt11 activity. We now find that Crescent also regulates the BMP pathway. Crescent expression was increased by the BMP antagonist Chordin and repressed by BMP4, while the opposite was true for Sizzled. Crescent knock-down increased the expression of BMP target genes, and synergized with Sizzled morpholinos. Thus, Crescent loss-of-function is compensated by increased expression of its ventral counterpart Sizzled. Crescent overexpression dorsalized whole embryos but not ventral half-embryos, indicating that Crescent requires a dorsal component to exert its anti-BMP activity. Crescent protein lost its dorsalizing activity in Chordin-depleted embryos. When co-injected, Crescent and Chordin proteins greatly synergized in the dorsalization of Xenopus embryos. The molecular mechanism of these phenotypes is explained by the ability of Crescent to inhibit Tolloid metalloproteinases, which normally degrade Chordin. Enzyme kinetic studies showed that Crescent was a competitive inhibitor of Tolloid activity, which bound to Tolloid/BMP1 with a KDof 11 nM. In sum, Crescent is a new component of the D–V pathway, which functions as the dorsal counterpart of Sizzled, through the regulation of chordinases of the Tolloid family.