Molecular mechanism of the formation of the signaling center in the prospective hindbrain of vertebrate early embryos

脊椎动物早期胚胎前脑信号中心形成的分子机制

基本信息

批准号：
17570170
负责人：
YAMASU Kyo
金额：
$ 2.43万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

1. The regulatory mechanism of zebrafish hoxb1b, which is expressed in the caudal neural plate to specify the position of rhombomere 1 in the hindbrain, was examined by the reporter analysis, revealing that hoxb1b expression was specifically driven in the neural plate by two downstream regions, d1 and d4. It was found that these two regions regulate hoxb1b in response to retinoic acid (RA) via two retinoic acid responsive regions (RAREs).2. Pou2 is known to be expressed transiently in the midbrain and hindbrain in late gastrulae, allowing for the development of the midbrain-hindbrain boundary (MHB) and hindbrain. Its regulatory mechanism was examined, showing that pou2 is spatially regulated mainly by the upstream 2.1-kb DNA, that the expression is maintained through an autoregulatory loop mediated by the cooperative function of four Pou2-binding Octamer sequences in the 2.1-kb DNA, and that pou2 is repressed by RA through a RARE in the upstream DNA.3. The internal structure of the late MHB enhancer of fgf8 was examined by introducing different deletions, showing that the MHB enhancer is activated broadly from the midbrain to r5 in the hindbrain by the two Pax2 binding sequences therein, and that a 28-bp region in this enhancer represses expression in the midbrain and posterior hindbrain, giving MHBspecific expression of fgf8. It was also found that this MHB enhancer is broadly conserved during vertebrate evolution.4. Mutant screen was conducted with zebrafish treated with ENU, leading to isolation of a mutant line (aa6k) that shows defects in the midbrain and hindbrain. Besides the brain defect, the mutant embryos have anomalies in touch response and significant jaw defects. The linkage analysis localized the mutation resides in chromosome 3, and revealed several close SSLP markers. Possible involvement of several candidate genes in aa6k mutation is now under investigation.

1。在尾神经板上表达的斑马鱼Hoxb1b的调节机制通过记者分析检查了指定菱形1在后脑脑中的位置，揭示了HOXB1B表达是由两个下游区域D1和D4在神经板中特别驱动的。发现这两个区域通过两个视黄酸反应性区域（RARES）对视黄酸（RA）调节HOXB1B .2。已知POU2在胃后期的中脑和后脑瞬时表达，从而允许中间脑 - 印度脑边界（MHB）和后脑的发展。研究了其调节机制，表明POU2主要由上游2.1-kb DNA在空间上调节，表达是通过由四个POU2结合八聚体序列的自动调节循环介导的2.1-Kb dNA中的2.1-kb dna中的自动调节循环，并且POU2在POU2中通过RAR rair rair rair rair rair rair rair rair raireds rain rain rar par in a pare in the Pare in the Pare in.3.33.33.333.33.33.33.33.33333.3333.33.33333。 The internal structure of the late MHB enhancer of fgf8 was examined by introducing different deletions, showing that the MHB enhancer is activated broadly from the midbrain to r5 in the hindbrain by the two Pax2 binding sequences therein, and that a 28-bp region in this enhancer represses expression in the midbrain and posterior hindbrain, giving MHBspecific expression of fgf8.还发现该MHB增强子在脊椎动物演化过程中是广泛保守的。4。用用ENU处理的斑马鱼进行突变筛查，从而分离突变线（AA6K），该突变线（AA6K）显示中脑和后脑的缺陷。除了大脑缺陷外，突变胚胎还具有触摸反应异常和明显的下颌缺陷。连锁分析将突变定位在3号染色体中，并揭示了几个紧密的SSLP标记。现在正在研究几个候选基因参与AA6K突变。