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

Molecular mechanisms of determination of limb region and identity

确定肢体区域和身份的分子机制

基本信息

批准号：
13480242
负责人：
TAMURA Koji
金额：
$ 11.01万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13480242/
关键词：
Development Limb Limb bud Tbx Pattern formation Anterior-posterior axis Tereost Gene 胚芽形態形成鰭 identity 体節誘導前肢後肢遺伝子発現軟骨魚類

项目摘要

1.Mechanism of regionalization of splanchnic/somatic lateral plateOur explant studies showed that the lateral plate mesoderm, which eventually is separated into splanchnic/somatic layers, has already been regionalized along the anterior-posterior axis, and they suggested that the two layers specify their antero-posterior patttern according to the regionalization (somatic makes forelimb, flank, and hindlimb, and splanchnic forms stomach, gizzard, small intestine, and large intestine).2.Specification of forelimb/hindlimb identityWe proposed a model that outset of determination to make limb identity is significantly different between forelimb and hindlimb, and that an inhibitory effect plays an important role for this determination (Saito et al., 2002). We further investigated which tissue or region involves the inhibitory factor. Somites at the wing level, implanted into leg region, inhibited the Tbx4 expression in the hindlimb region and induced the Tbx5 expression there. These results suggest that somite may be a source of the inhibitory effect that determines limb identity.3.Fin development of cartilaginous fishesWe have constructed a system to get eggs of cartilaginous fishes continually, and cloned several key genes including Tbx5, Tbx4, Pitxl, shh, fgf8 and msx from two species of cartilaginous fishes, (shark and ray). Especially, existence of Tbx5/4 in cartilaginous fishes strongly suggests that all groups of vertebrates which have limb/fin possess the limb identity regulated by Tbx gene expression (Tamura et al., 2001). Taken together with the expression pattern of msx gene in cartilaginous fishes, we also suggested that flank region between forelimb and hindlimb of cartilaginous fishes has a potential for making limb as well.

1.1 .我们的外植体研究表明，外侧板中胚层已沿前后轴呈区域化分布，并最终分化为内脏/躯体层，我们认为这两层已根据区域化划分出各自的前后格局（躯体形成前肢、侧翼和后肢，内脏形成胃、胗、小肠和大肠）。前肢/后肢身份的规范我们提出了一个模型，即前肢和后肢对肢体身份的决定开始有显著差异，并且抑制效应在这一决定中起着重要作用（Saito et al., 2002）。我们进一步研究了哪个组织或区域涉及抑制因子。部分细胞在翅膀水平植入腿区，抑制后肢Tbx4表达，诱导后肢Tbx5表达。这些结果表明，有些可能是抑制作用的一个来源，决定肢体的身份。构建了软骨鱼类鱼卵连续获取系统，克隆了两种软骨鱼类（鲨鱼和鳐）的Tbx5、Tbx4、Pitxl、shh、fgf8和msx等关键基因。特别是，在软骨鱼中存在Tbx5/4强烈表明，所有具有肢体/鳍的脊椎动物群体都具有Tbx基因表达调控的肢体身份（Tamura et al., 2001）。结合msx基因在软骨鱼体内的表达模式，我们也认为软骨鱼前肢和后肢之间的侧腹区域也有可能产生肢体。