A nuclear localization signal and the C-terminal omega sequence in the Agrobacterium tumefaciens VirD2 endonuclease are important for tumor formation.
A nuclear localization signal and the C-terminal omega sequence in the Agrobacterium tumefaciens VirD2 endonuclease are important for tumor formation.
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DOI：
10.1073/pnas.89.24.11837
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发表时间：
1992-12
影响因子：
11.1
通讯作者：
C. E. Shurvinton;L. Hodges;W. Ream
中科院分区：
文献类型：
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作者：
C. E. Shurvinton;L. Hodges;W. Ream
根癌农杆菌肿瘤诱导（Ti）质粒的T-DNA部分整合到植物核DNA中。直接重复序列定义T-DNA末端;当VirD 2内切核酸酶在右侧边界重复序列中产生位点特异性切口并连接到切口链的5'末端时，转移开始。随后的事件产生线性单链VirD 2结合的DNA分子，包括整个T-DNA（T链）。VirD 2蛋白在C末端附近含有核定位信号（NLS），并且可以将结合的T-链引导至植物核。我们在virD 2中构建了突变，并表明NLS对肿瘤发生很重要，尽管T链的产生在其缺失时正常发生。烟草蚀纹病毒NLS，取代VirD 2 NLS，恢复肿瘤诱导活性。氨基酸（ω序列）在C末端的VirD 2，外的NLS和核酸内切酶结构域，有助于显着的肿瘤发生，这表明VirD 2可能是第三个重要的功能，在T-DNA转移。
The T-DNA portion of the Agrobacterium tumefaciens tumor-inducing (Ti) plasmid integrates into plant nuclear DNA. Direct repeats define the T-DNA ends; transfer begins when the VirD2 endonuclease produces a site-specific nick in the right-hand border repeat and attaches to the 5' end of the nicked strand. Subsequent events generate linear single-stranded VirD2-bound DNA molecules that include the entire T-DNA (T-strands). VirD2 protein contains a nuclear localization signal (NLS) near the C terminus and may direct bound T-strands to plant nuclei. We constructed mutations in virD2 and showed that the NLS was important for tumorigenesis, although T-strand production occurred normally in its absence. A tobacco etch virus NLS, substituted for the VirD2 NLS, restored tumor-inducing activity. Amino acids (the omega sequence) at the C terminus of VirD2, outside the NLS and the endonuclease domain, contributed significantly to tumorigenesis, suggesting that VirD2 may serve a third important function in T-DNA transfer.