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

Study of novel Ras signaling pathway using ras knockout mice

使用ras基因敲除小鼠研究新型Ras信号通路

基本信息

批准号：
10480197
负责人：
AIBA Atsu
金额：
$ 7.87万
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：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10480197/
关键词：
H-ras N-ras K-ras knockout mouse double knockout mouse transgenic mouse tyrosine phosphorylation MAPキナーゼ Ras NMDA受容体 NR1 NR2B カルシウム ERK Src Fyn

项目摘要

We generated H-ras, N-ras and K-ras deficient mice and multiple ras mutant mice, and found that H-ras and N-ras mutant mice as well as H-ras N-ras double mutant mice apparently developed normally, but K-ras mutant mice were embryonic lethal. We introduced human H-ras transgene into a single and multiple ras mutant mice and found that H-ras transgene rescue all abnormality exhibited in the development of these ras mutant mice, suggesting that the function of ras genes is redundant in embryonic and neonatal development.We showed that H-ras null mutant mice develop approximately seven times less papillomas compared with wild-type littermates do after 20 weeks of TPA treatment. 13 (62%) out of 21 papillomas in H-ras null mutant mice have activated mutations of K-ras gene. This suggests that activation of K-ras gene can replace the H-ras activation in the initiation step of skin tumor development.In the H-ras null mutant hippocampus, the tyrosine phosphorylation of NR2A (ε1) and NR2B (ε2) subunits of NMDA receptors is increased and correspondingly NMDA synaptic responses are selectively enhanced. In addition, long-term potentiation (LTP) is markedly enhanced in mutant mice most likely due to a selective enhancement of NMDA synaptic responses. Therefore, although Ras proteins have been implicated in cell proliferation and differentiation, the regulation of activity-dependent synaptic plasticity in the adult animals by downregulation of the phosphorylation of the NMDA receptor may be another major and pivotal role for H-Ras protein. To investigate the relationship between Ras signaling pathway and NMDA receptor, we stimulate hippocampal culture cell by NMDA.We found that dephosphorylation of NMDA receptor occured as well as activation of ERK and p38 MAPK.We found that the activation of ERK by NMDA stimulation requires Ras activity.

本研究制备了H-ras、N-ras和K-ras基因缺陷小鼠和多个ras基因突变小鼠，发现H-ras和N-ras基因突变小鼠以及H-ras和N-ras基因双突变小鼠发育正常，而K-ras基因突变小鼠具有胚胎致死性。我们将人H-ras转基因导入单个和多个ras突变小鼠中，发现H-ras转基因挽救了这些ras突变小鼠发育中表现出的所有异常，表明ras基因在胚胎和新生儿发育中的功能是多余的。我们发现，在TPA治疗20周后，H-ras无效突变小鼠与野生型同窝小鼠相比，乳头状瘤的发生率约低7倍。21例H-ras基因敲除小鼠乳头状瘤中13例（62%）存在K-ras基因激活突变。在H-ras缺失突变的海马中，NMDA受体NR 2A（ε1）和NR 2B（ε2）亚单位的酪氨酸磷酸化水平增加，相应的NMDA突触反应选择性增强。此外，突变小鼠的长时程增强（LTP）显著增强，很可能是由于NMDA突触反应的选择性增强。因此，尽管Ras蛋白与细胞增殖和分化有关，但通过下调NMDA受体的磷酸化来调节成年动物中的活性依赖性突触可塑性可能是H-Ras蛋白的另一个主要和关键作用。为探讨Ras信号通路与NMDA受体的关系，我们用NMDA刺激海马培养细胞，发现NMDA受体的去磷酸化与ERK和p38 MAPK的激活同时发生，发现NMDA刺激ERK激活需要Ras活性。