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Molecular bases of initial processes for formation of crown gall tumor

冠瘿瘤形成初始过程的分子基础

基本信息

批准号：
02404003
负责人：
MACHIDA Yasunori
金额：
$ 20.54万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02404003/
关键词：
Agrobacterium T-DNA Crown gall tumor Plants Ti plasmid vir genes TーDNA クラウンゴ-ル腫瘍

项目摘要

(1)Mechanisms of plant signal perception by Agrobacterium We have demonstrated that the periplasmic domain and TM2 of a VirA sensor protein are involved in recognition of sugar signal, but not in that of phenolic signal. We have isolated chvE mutations which restore enhancement of vir induction by sugars in the vir A mutant which shows a sugar-non-responsive phenotype. This result indicates that the ChvE protein physically interacts with the VirA protein in the signal pathway mediated by these proteins. (2)vir genes responsible for movement of T-DNA from Agrobacterium to plant cells We have that products of virB and virD4 genes are strictly required for transfer of T-DNA from Agrobacterium to plant cells and that a product of virE2 markedly potentiates this process, but is not essential. (3)Integration of T-DNA into plant nuclear DNA We have shown that in each case of two T-DNA-transformed tobacco tumors, significant sequence homology is present between the region adjacent to the integration target site and both external regions of the T-DNA breakpoints. These findings suggest that sequence homology between the incoming T-DNA and plant chromosomal DNA has an important function in T-DNA integration. We also found that members of a new family of SINE (short interspersed DNA element), which is designated as the TS family, were present in DNA region adjacent to T-DNA integration targets of tobacco chromosomes. A relationship between integration events of T-DNA and the Ts family remains to be proved.

（1）农杆菌感受植物信号的机制我们已经证明VirA感受蛋白的周质结构域和TM 2参与糖信号的识别，但不参与酚信号的识别。我们已经分离出chvE突变，其恢复了vir A突变体中糖对vir诱导的增强，该突变体显示糖非应答表型。该结果表明，ChvE蛋白在由这些蛋白介导的信号通路中与VirA蛋白物理相互作用。（2）负责将T-DNA从农杆菌转移到植物细胞的vir基因我们知道，将T-DNA从农杆菌转移到植物细胞严格需要virB和virD 4基因的产物，并且virE 2的产物显著地增强了这一过程，但不是必需的。（3）T-DNA整合到植物核DNA中我们已经表明，在两个T-DNA转化的烟草肿瘤的每一种情况下，在邻近整合靶位点的区域和T-DNA断裂点的两个外部区域之间存在显著的序列同源性。这些发现表明，传入的T-DNA和植物染色体DNA之间的序列同源性在T-DNA整合中具有重要作用。我们还发现在烟草染色体T-DNA整合靶区附近存在一个新的SINE（short interspersed DNA element）家族成员，命名为TS家族。T-DNA整合事件与Ts家族的关系尚待证实。