Piccolo S, Sasai Y, Lu B, De Robertis E M
Howard Hughes Medical Institute, Department of Biological Chemistry, University of California, Los Angeles 90035-1737, USA.
Cell. 1996 Aug 23;86(4):589-98. doi: 10.1016/s0092-8674(00)80132-4.
Chordin (Chd) is an abundant protein secreted by Spemann organizer tissue during gastrulation. Chd antagonizes signaling by mature bone morphogenetic proteins (BMPs) by blocking binding to their receptors. Recombinant Xenopus Chd binds to BMP-4 with high affinity (KD, 3 x 10(-10) M), binding specifically to BMPs but not to activin or TGF-beta1. Chd protein is able to dorsalize mesoderm and to neuralize ectoderm in Xenopus gastrula explants at 1 nM. We propose that the noncell-autonomous effects of Spemann's organizer on dorsoventral patterning are executed in part by diffusible signals that directly bind to and neutralize ventral BMPs during gastrulation.
脊索蛋白（Chd）是原肠胚形成过程中由施佩曼组织者组织分泌的一种丰富蛋白质。Chd通过阻断成熟骨形态发生蛋白（BMPs）与其受体的结合来拮抗其信号传导。重组非洲爪蟾Chd与BMP-4具有高亲和力结合（解离常数KD为3×10⁻¹⁰M），特异性结合BMPs，但不结合激活素或转化生长因子β1。Chd蛋白在1 nM浓度下能够使非洲爪蟾原肠胚外植体中的中胚层背化并使外胚层神经化。我们提出，施佩曼组织者对背腹模式形成的非细胞自主效应部分是由可扩散信号执行的，这些信号在原肠胚形成过程中直接结合并中和腹侧BMPs。
