Repression of nodal expression by maternal B1-type SOXs regulates germ layer formation in Xenopus and zebrafish.
Repression of nodal expression by maternal B1-type SOXs regulates germ layer formation in Xenopus and zebrafish.
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DOI：
10.1016/j.ydbio.2004.05.019
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发表时间：
2004-09
影响因子：
2.7
通讯作者：
Chi Zhang;T. Basta;L. Hernandez‐Lagunas;P. Simpson;D. Stemple;K. Artinger;M. Klymkowsky
中科院分区：
文献类型：
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作者：
Chi Zhang;T. Basta;L. Hernandez‐Lagunas;P. Simpson;D. Stemple;K. Artinger;M. Klymkowsky
B1型SOX（SOX 1，2和3）是SOX转录因子家族中进化上最保守的亚群。为了研究它们的母体功能，我们使用亲和纯化的抗体抗SOX 3c，其抑制爪蟾SOX 3与靶DNA序列的结合[Development. 130（2003）5609]。该抗体也与斑马鱼胚胎发生交叉反应。当注射到受精的非洲爪蟾或斑马鱼卵中时，抗SOX 3c引起了严重的原肠胚形成缺陷;这种缺陷可以通过注射编码SOX 3 ΔC-EnR的RNA来挽救，SOX 3 ΔC-EnR是一种SOX 3捕获的抑制结构域嵌合体。在抗SOX 3c注射非洲爪蟾胚胎，中胚层和内胚层标记的正常动物-植物模式被破坏，表达域向动物极转移，内胚层标记物SOX 17和内胚层蛋白的水平增加。在非洲爪蟾中，SOX 3作为Xnr 5的负调节因子，Xnr 5编码与肾脏相关的TGFβ家族蛋白。两种与神经系统相关的蛋白质在早期斑马鱼胚胎中表达，斜视和剑水蚤;抗SOX 3c注射导致剑水蚤表达水平的增加。在非洲爪蟾和斑马鱼中，通过注射编码节点抑制剂Cerberus-短（CerS）的RNA来拯救抗SOX 3c表型。在非洲爪蟾中，通过注射编码Mixer显性负性版本或针对SOX 17 α2的吗啉代的RNA抑制了抗SOX 3c对内胚层蛋白表达的作用，这两种RNA均作用于内胚层特化途径中的节点信号传导下游。基于这些数据，似乎母体B1型SOX与VegT/β-catenin系统一起发挥作用，以调节结节表达并建立爪蟾胚层形成的正常模式。一个机械保守的系统似乎在斑马鱼中以类似的方式起作用。
B1-type SOXs (SOXs 1, 2, and 3) are the most evolutionarily conserved subgroup of the SOX transcription factor family. To study their maternal functions, we used the affinity-purified antibody antiSOX3c, which inhibits the binding of Xenopus SOX3 to target DNA sequences [Development. 130(2003)5609]. The antibody also cross-reacts with zebrafish embryos. When injected into fertilized Xenopus or zebrafish eggs, antiSOX3c caused a profound gastrulation defect; this defect could be rescued by the injection of RNA encoding SOX3ΔC-EnR, a SOX3-engrailed repression domain chimera. In antiSOX3c-injected Xenopus embryos, normal animal–vegetal patterning of mesodermal and endodermal markers was disrupted, expression domains were shifted toward the animal pole, and the levels of the endodermal markers SOX17 and endodermin increased. In Xenopus, SOX3 acts as a negative regulator of Xnr5, which encodes a nodal-related TGFβ-family protein. Two nodal-related proteins are expressed in the early zebrafish embryo, squint and cyclops; antiSOX3c-injection leads to an increase in the level of cyclops expression. In both Xenopus and zebrafish, the antiSOX3c phenotype was rescued by the injection of RNA encoding the nodal inhibitor Cerberus-short (CerS). In Xenopus, antiSOX3c's effects on endodermin expression were suppressed by injection of RNA encoding a dominant negative version of Mixer or a morpholino against SOX17α2, both of which act downstream of nodal signaling in the endoderm specification pathway. Based on these data, it appears that maternal B1-type SOX functions together with the VegT/β-catenin system to regulate nodal expression and to establish the normal pattern of germ layer formation in Xenopus. A mechanistically conserved system appears to act in a similar manner in the zebrafish.