ROLE OF SIF PROTEIN IN SYNAPTOGENESIS

SIF 蛋白在突触发生中的作用

基本信息

批准号：
09680784
负责人：
HAMA Chihiro
金额：
$ 2.11万
依托单位：
NATIONAL CENTER OF NEUROLOGY AND PSYCHIATRY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680784/
关键词：
GUANINE NUCLEOTIDE EXCHANGE FACTOR RHO MUTATION DROSOPHILA NERVOUS SYSTEM PLASTICITY SYNAPSE SIF SIFタンパク質 still life GTPase 分子生物学

项目摘要

We are interested in understanding the molecular mechanisms that regulate synaptogenesis. To approach this issue, we have employed genetics of Drosophila and screened mutant flies that show reduced locomotor activity at the adult stage. One of the mutant strains idetified during this screening is still life (sit), which was later found to encode a gulanine nucleotide exchange factor that specifically reacts for Rac1 in vitro. Interestingly, this protein was found to localize at the submemebraneous regions of the periactive zones that surround the active zones in the synaptic terminals. The goal of this project is to reveal the in vivo function of SIF protein in the synaptic terminals by analyzing the sif mutant animals.Our genetic screen to 9000 chromosomes treated with ethylmethane sulfonate, a chemical mutagen, successfully identifed more than 10 sif mutant alleles. Western blotting and sequencing analyses further revealed that 2 of them have terminal-codon mutations, each causing functional null. These mutant animals are not homozygously lethal but show reduced locomotor activity. We have not so far succeeded in identifying clear morphological phenotypes at both light and electron microscopic levels. It is however possible that sif may be involved in refinement of synaptic arborization that occurrs during synaptogenesis or responding to neural activity. To test this hypothesis, we have tried to visualize a small number of neurites in the adult brain using GFP and to find any effects of sif mutation on their morphology.

我们有兴趣了解调节突触发生的分子机制。为了解决这个问题，我们利用果蝇遗传学并筛选了在成虫阶段表现出运动活性降低的突变果蝇。此次筛选过程中鉴定出的突变株之一是 still life (sit)，后来发现它编码一种在体外与 Rac1 发生特异性反应的古丙氨酸核苷酸交换因子。有趣的是，这种蛋白质被发现定位于突触末端活跃区周围活跃区的膜下区域。该项目的目标是通过分析sif突变动物，揭示SIF蛋白在突触末端的体内功能。我们对经过化学诱变剂甲磺酸乙酯处理的9000条染色体进行遗传筛选，成功鉴定出10多个sif突变等位基因。蛋白质印迹和测序分析进一步表明，其中 2 个具有末端密码子突变，每个突变都会导致功能无效。这些突变动物不是纯合致死的，但表现出运动活性降低。迄今为止，我们尚未成功地在光显微镜和电子显微镜水平上鉴定出清晰的形态表型。然而，sif 可能参与突触发生或响应神经活动期间发生的突触树枝化的细化。为了检验这一假设，我们尝试使用 GFP 可视化成人大脑中的少量神经突，并找出 sif 突变对其形态的影响。