在Xenopus胚胎中,通过蛋背部决定因素诱导轴向发育的双重保证
Yagmur Azbazdar1, Edward M De Robertis1
1Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1662.
概括
在Xenopus胚胎中的两个信号中心,Nieuwkoop和Blastula Chordin和Noggin表达 (BCNE) 中心,独立地确保轴形成. 这两个中心都激活了类似的下游基因,Siamois和Xnrs在平行路径上起作用.
科学领域:
- 发育生物学是发展生物学.
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
背景情况:
- 在Xenopus胚胎中,β-catenin稳定会诱导两个关键的信号中心:Nieuwkoop中心 (介导Xnr信号) 和芽细胞合并和诺金表达 (BCNE) 中心 (涉及Siamois).
- 节点对手Cerberus-short (CerS) 抑制了Nieuwkoop中心的功能.
- 此前,BCNE中心的作用及其与Nieuwkoop中心的关系尚不清楚.
研究的目的:
- 调查Xenopus结节相关 (Xnr) 蛋白与胚胎轴形成中的Siamois (Sia) 家庭盒基因之间的功能关系.
- 为了确定Xnrs和Sia在建立信号中心时是否依赖或在平行路径上起作用.
- 阐明下游目标,如Chordin在轴发展中的作用.
主要方法:
- 将编码Xnrs和Sia的mRNA微注入β-catenin缺少的Xenopus胚胎中.
- 下游目标的Morpholino介导的枯竭,包括Chordin.
- 下游组织者特定基因表达的分析.
- 研究Huluwa mRNA注射和Chordin枯竭的影响.
主要成果:
- 在缺乏β-catenin的胚胎中,Xnrs和Sia的同时表达挽救了带头和眼睛的完整的背轴.
- Xnrs和Sia在平行路径上起作用,因为它们都没有激活对方的表达,尽管它们都被β-catenin诱导.
- 胆固醇枯竭阻断了Huluwa的子宫外效应,包括大脑组织扩张和的基因表达.
- 这两个中心独立地激活了类似的下游转录目标.
结论:
- 纽纽科普和BCNE中心通过独立激活类似的下游基因库,为轴向形成提供冗余机制.
- 西莫斯可能代表了Xenopus特定的适应祖先的混合型家庭主体蛋白质 (Sebox) 的前神经板分化.
- 在轴模拟过程中,丁在调解像Huluwa这样的母性决定因素的影响方面发挥着至关重要的作用.
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