The repressor function of Snail is required for Drosophila gastrulation and is not replaceable by Escargot or Worniu
The repressor function of Snail is required for Drosophila gastrulation and is not replaceable by Escargot or Worniu
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DOI：
10.1016/j.ydbio.2004.01.029
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发表时间：
2004-05-13
影响因子：
2.7
通讯作者：
Ip, YT
中科院分区：
文献类型：
--
作者：
Hemavathy, K;Hu, XD;Ip, YT
果蝇胚胎中胚层的形成依赖于母体Toll信号通路。Toll通路建立背核梯度，其调节许多合子基因以建立中胚层命运并促进腹侧细胞的内陷。Dorsal的一个重要靶基因是snail，这是中胚层适当内陷所必需的。Snail蛋白含有五个锌指，是一种转录抑制因子。然而，目前尚不清楚是否抑制靶基因是蜗牛控制腹侧内陷的必要条件。为了验证这种要求，我们在蜗牛突变体胚胎中进行了一系列遗传拯救实验。Snail、Worniu和Escargot是密切相关的锌指蛋白，在成神经细胞发育过程中具有相同的功能。然而，在这三种蛋白中，只有Snail可以拯救中胚层内陷表型。此外，各种Snail突变体构建体抑制基因表达的能力与它们控制内陷的能力相关。Snail在中胚层形成中的这种独特性质主要归因于N端的CtBP辅阻遏物相互作用基序，而不是C端DNA结合锌指。Snail在腹侧区域外的异位表达不足以诱导细胞运动，即使靶基因的抑制仍然发生。总之，这些结果表明Snail的阻遏物功能对于原肠胚形成是必不可少的。Snail对靶基因的抑制可能允许腹侧细胞中的其他因子积极促进中胚层内陷。(C)2004爱思唯尔公司All rights reserved.
Mesoderm formation in the Drosophila embryo depends on the maternal Toll signaling pathway. The Toll pathway establishes the Dorsal nuclear gradient, which regulates many zygotic genes to establish the mesodermal fate and promote the invagination of ventral cells. An important target gene of Dorsal is snail, which is required for proper mesoderm invagination. The Snail protein contains five zinc fingers and is a transcriptional repressor. However, it is not clear whether repressing target genes is a requirement for Snail to control ventral invagination. To examine such requirement, we conducted a series of genetic rescue experiments in snail mutant embryos. Snail, Worniu, and Escargot are closely related zinc-finger proteins and have equal functions during neuroblast development. However, among these three proteins, only Snail can rescue the mesoderm invagination phenotype. Moreover, the ability of various Snail mutant constructs to repress gene expression correlates with their ability to control invagination. This unique property of Snail in mesoderm formation can be attributed mostly to the CtBP co-repressor interaction motifs in the N-terminus, not to the C-terminal DNA-binding zinc fingers. Ectopic expression of Snail outside the ventral domain is not sufficient to induce cell movement even though repression of target genes still occurs. Together, the results show that the repressor function of Snail is essential for gastrulation. The repression of target genes by Snail may permit other factors in the ventral cells to positively promote mesoderm invagination. (C) 2004 Elsevier Inc. All rights reserved.