权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Analysis on molecular mechanisms of neuralization and early patterning in the formation of the presumptive midbrain-hindbrain boundary region

假定中脑-后脑边界区域形成中神经化和早期模式形成的分子机制分析

基本信息

批准号：
16370076
负责人：
TAIRA Masanori
金额：
$ 9.92万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

To explore the molecular mechanism of neuralization and early pattern formation in vertebrate embryos, we investigated the following two subjects.1) Functional analysis of XHR1 : ESR1 is a bHLH transcriptional repressor gene, and was identified as a candidate for XHR1 target genes. We performed (1) gene activation analysis using a XRH1-VP16-GR construct and a protein synthesis inhibitor, (2) gain-of-function analysis of XHR1 and ESR1, and (3) loss-of-function analysis using antisense-morpholino oligos for XHR1. We showed that ESR is a direct target of XHR1 ; that XHR1 is necessary and sufficient for suppression of ESR1 expression; and that overexpression of ESR1 represses the MHB gene Pax2. Furthermore, in contrast to ESR1, XHR1 was not activated by Notch signaling, and XHR1 directly repressed neuronal genes, neurogenin and delta. These data suggest that XHR1 functions as a prepattern gene for MHB formation as well as for proneural cluster formation by repressing neuronal differentiati … More on2) Analysis of XHR1 gene regulation : We cloned and analyzed a Xenopus tropicalis HR1 (XtHR1) promoter, which faithfully recapitulated the endogenous XHR1 expression. Surprisingly, transgenic and animal cap assays revealed distinct enhancers, named the early and late enhancer modules (the EEM and LEM), that govern XHR1 expression in pre-MHB and MHB regions, respectively. Furthermore, the EEM was found to integrate Noggin, Wnt, and FGF signals. Gain-of-function and dominant-negative approaches in vivo showed that neural inducers activate XHR1 ; Wnt signaling confines XHR1 expression; and moderate and strong FGF signaling enhances and suppresses XHR1 expression, respectively. These data suggest that the XHR1 expression of the pre-MHB region is induced through the EEM by signaling molecules from the Spemann organizer.Thus, we have shown the molecular mechanism of XHR1 induction in the pre-MHB region and a molecular cascade mediated by XHR1 from the pre-MHB to the MHB region, an organizing center of brain formation. Less

为了探讨脊椎动物胚胎神经化和早期模式形成的分子机制，我们研究了以下两个主题。1) XHR1功能分析：ESR1是bHLH转录抑制基因，被确定为XHR1靶基因的候选基因。我们使用XRH1-VP16-GR构建体和蛋白质合成抑制剂进行了(1)基因激活分析，(2)XHR1和ESR1的功能获得分析，(3)XHR1的功能丧失分析使用反义形态学寡核苷酸。我们发现ESR是XHR1的直接靶点；XHR1是抑制ESR1表达的必要和充分条件；并且ESR1的过表达会抑制MHB基因Pax2。此外，与ESR1相比，XHR1不被Notch信号激活，XHR1直接抑制神经元基因、神经原素和δ。这些数据表明，XHR1作为MHB形成的前模式基因，并通过抑制神经元分化而形成前神经簇。更多关于XHR1基因调控的分析：我们克隆并分析了热带爪蟾HR1 （XtHR1）启动子，该启动子真实地再现了内源性XHR1的表达。令人惊讶的是，转基因和动物帽分析揭示了不同的增强子，分别命名为早期和晚期增强子模块（EEM和LEM），它们分别控制MHB前和MHB区域的XHR1表达。此外，EEM还整合了Noggin、Wnt和FGF信号。体内功能获得和显性阴性方法表明，神经诱导剂激活XHR1；Wnt信号限制XHR1的表达；适度和强烈FGF信号分别增强和抑制XHR1的表达。这些数据表明，前mhb区域的XHR1表达是通过Spemann组织者的信号分子通过EEM诱导的。因此，我们已经展示了XHR1在MHB前区诱导的分子机制，以及由XHR1介导的从MHB前区到MHB区（脑形成的组织中心）的分子级联反应。少

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Systematic screening for genes specifically expressed in the anterior neuroectoderm during early Xenopus development

系统筛选爪蟾早期发育过程中前神经外胚层特异表达的基因

DOI：
发表时间：
2005
期刊：
Int.J.Dev.Biol. 49
影响因子：
0
作者：
Takada;H.;Hattori;D.;Kitayama;A.;Ueno;N.;Taira;M.;Hitomi Takada;Mikihito Shibata;Noriyuki Takahashi
通讯作者：
Noriyuki Takahashi

Identification of target genes for the Xenopus Hes-related protein XHR1, a prepattern factor specifying the midbrain-hindbrain boundary