Mechanizms of Regionalizaion of the tectum and cerebellum and retinotectal projection

顶盖和小脑的区域化机制以及视网膜顶盖投射

• 批准号: 15207016
• 负责人: NAKAMURA Harukazu
• 金额: $ 32.2万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15207016/
• 关键词: chick embryo; cerebellum; Fgf8-Ras-ERK signaling cascade; organizer; Sprouty2; regulation; misexpression; tectum; 峡部; Fgf8; Ras-ERKシグナル伝達系; エレクトロポレーション; Ras-ERKシグナル経路; siRNA; 遺伝子発現阻害

The isthmus works as an organizer, and Fgf8 mimics the organizing activity. The isthmic organizer plays a role for the development of the tectum and the cerebellum in the mesencephalon and in the metencephalon, respectively. It was previously shown that strong Fgf8 signal induces cerebellar differentiation. In the present study, we have shown that strong Fgf8 signal activates Ras-ERK signaling cascade. If we shut down this signaling cascade by misexpression of dominant negative form of Ras (DN-Ras), y electroporation the fate of the metencephalon changes to the mesencephalon, and the tectum differentiates in place of the cerebellum. Then, we focused on Sprouty2. Sprouty2 is expressed overlapping to Fgf8, but was indicated as a negative regulator of Ras-ERK signaling cascade. As indicated, Sprouty2 expression was induced rapidly by Fgf8, that is, 2 hours after electroporation of Fgf8 expression vector, and repressed ERK activation. Misexpression of Sprouty2 exerted similar results as that of DN-Ras, that is, fate change of the metencephalon to the mesencephalon. On the other hand, misexpression of dominant negative form of Sprouty2 resulted in anterior shift of the mes-metencephalic boundary. The results indicate the need of fine regulation of Ras-ERK signaling.

峡部起组织者的作用，而Fgf8模仿组织活动。峡部组织者在中脑和后脑分别对顶盖和小脑的发育起作用。以往的研究表明，强的Fgf8信号诱导小脑分化。在本研究中，我们发现强烈的Fgf8信号激活了RAS-ERK信号级联反应。如果我们通过错误表达显性负性RAS(dN-RAS)来关闭这一信号级联，y电穿孔，则后脑的命运改变为中脑，顶盖分化而不是小脑。然后，我们将重点放在Sprouty2上。Sprouty2与Fgf8重叠表达，但被认为是Ras-ERK信号级联的负调控因子。结果表明，Fgf8能迅速诱导Sprouty2的表达，即在电穿孔表达载体后2小时，抑制ERK的激活。Sprouty2的错误表达产生了与dN-RAS相似的结果，即后脑向中脑的命运改变。另一方面，Sprouty2显性阴性形式的错误表达导致了中-中脑边界的前移。结果表明，需要对RAS-ERK信号进行精细调控。

项目成果

The Fgf8 signal causes cerebellar differentiation by activating Ras-ERK signaling pathway

Fgf8信号通过激活Ras-ERK信号通路引起小脑分化

• 发表时间: 2004
• 期刊: Development 131
• 作者: Sato;R.;Nakamuram;H
• 通讯作者: H

Nakamura, H., Sugiyama, S.: "Polarity and laminar formation of the optic tectum in relation to retinal projection."J.Neurobiol.. 59・1. 48-56 (2004)

Nakamura, H., Sugiyama, S.：“与视网膜投影相关的视顶盖的极性和层状形成。”J.Neurobiol.. 59・1 (2004)。

峡部オーガナイザーによる小脳分化の制御

峡部组织者对小脑分化的控制

• 发表时间: 2005
• 期刊: 実験医学 23
• 作者: Nakano;K.;Arai;R.;Mabuchi;I.;齋藤都暁ら;仲村春和
• 通讯作者: 仲村春和

Nakamura, H., Katahira, T., Watanabe, Y., Funahashi, J.: "Gain and loss of function in chick embroys by electroporation"Mech.Dev.. (in press).

Nakamura, H.、Katahira, T.、Watanabe, Y.、Funahashi, J.：“通过电穿孔获得和丧失鸡胚功能”Mech.Dev..（出版中）。

Katahira, T., Nakamura, H.: "Gene silencing in chick embryos with vector-based small interfering RNA system."Develop.Growth Differ.. 45・3. 361-367 (2003)

Katahira, T., Nakamura, H.：“利用基于载体的小干扰 RNA 系统进行鸡胚基因沉默。”Develop.Growth Differ.. 45・3 (2003)。