The left-right axis is regulated by the interplay of Coco, Xnr1 and derrière in Xenopus embryos.
The left-right axis is regulated by the interplay of Coco, Xnr1 and derrière in Xenopus embryos.
复制标题
爪蟾胚胎中左右轴由 Coco、Xnr1 和 derrière 的相互作用调节。
DOI：
10.1016/j.ydbio.2006.09.039
复制
发表时间：
2007
影响因子：
2.7
通讯作者：
Brivanlou,AliH
中科院分区：
文献类型：
--
作者：
Vonica,Alin;Brivanlou,AliH
左右轴的形成涉及起源于结节或其等价物的对称性破坏信号，它增加了胚胎左侧的转化生长因子-β信号，最终导致内脏的不对称图案。DAN结构域蛋白是转化生长因子-β配体的胞外抑制因子，参与调节鸡、小鼠和斑马鱼的左右轴。我们发现非洲爪哇丹家族成员Coco和两个转化生长因子-β配体Xnr1和DERRIère在神经胚期的后旁中胚层中共表达。侧特异性蛋白质耗尽表明，左右模式只需要右侧的Coco，只需要左侧的Xnr1和derrière，尽管它们的双边表达模式。在没有COCO的情况下，转化生长因子-β信号是双侧的。这三种蛋白质之间的相互作用表明，正常水平的Xnr1表达需要derrière，而Coco直接抑制这两种配体。我们的结论是，DERRIERE、Xnr1和COCO定义了一个转录后调控的信号中心，这是导致胚胎左侧转化生长因子-β信号增加的信号链中必要的一环。
Formation of the left–right axis involves a symmetry-breaking signal originating in the node or its equivalents, which increases TGF-β signaling on the left side of the embryo and ultimately leads to asymmetric patterning of the viscera. DAN domain proteins are extracellular inhibitors of TGF-β ligands, and are involved in regulating the left–right axis in chick, mouse and zebrafish. We find that Coco, a Xenopus DAN family member, and two TGF-β ligands, Xnr1 and derrière, are coexpressed in the posterior paraxial mesoderm at neurula stage. Side-specific protein depletion demonstrated that left–right patterning requires Coco exclusively on the right side, and Xnr1 and derrière exclusively on the left, despite their bilateral expression pattern. In the absence of Coco, the TGF-β signal is bilateral. Interactions among the three proteins show that derrière is required for normal levels of Xnr1 expression, while Coco directly inhibits both ligands. We conclude that derrière, Xnr1, and Coco define a posttranscriptionally regulated signaling center, which is a necessary link in the signaling chain leading to an increased TGF-β signal on the left side of the embryo.