van Haaren M J, Sedee N J, de Boer H A, Schilperoort R A, Hooykaas P J
Department of Plant Molecular Biology, Leiden University, Netherlands.
Plant Mol Biol. 1989 Nov;13(5):523-31. doi: 10.1007/BF00027312.
Left- and right-border repeats, which surround the T-region, contain two conserved regions separated by 5 bp that are not conserved. At the onset of T-DNA processing virD-encoded proteins introduce a nick in the largest of these conserved regions (12 bp) at a specific position in the bottom strand between a guanine and thymine nucleotide [2, 33]. In this paper we describe the effect of several site-directed mutations in the right-border repeat on tumorigenicity of Agrobacterium in plants. Our data show that mutations introduced directly around the nick site do not seriously affect the tumorigenicity of Agrobacterium, whereas mutations in the right part of this 12 bp conserved region do so. Furthermore, it appeared that the second conserved region (5 bp) is also essential for border activity and that the distance between the two conserved regions is important to obtain optimal border activity.
围绕T区域的左右边界重复序列包含两个保守区域，它们被5个碱基对隔开，这5个碱基对并不保守。在T-DNA加工开始时，virD编码的蛋白质在底部链上一个特定位置的最大保守区域（12个碱基对）中，在鸟嘌呤和胸腺嘧啶核苷酸之间引入一个切口[2, 33]。在本文中，我们描述了右边界重复序列中几个定点突变对根癌土壤杆菌在植物中致瘤性的影响。我们的数据表明，直接在切口位点周围引入的突变不会严重影响根癌土壤杆菌的致瘤性，而在这个12个碱基对保守区域右侧部分的突变则会产生影响。此外，似乎第二个保守区域（5个碱基对）对边界活性也至关重要，并且两个保守区域之间的距离对于获得最佳边界活性很重要。
