Department of Biology, Washington University, St. Louis, Missouri 63130.
Proc Natl Acad Sci U S A. 1982 Oct;79(20):6322-6. doi: 10.1073/pnas.79.20.6322.
Crown gall disease results from the insertion of a segment of the Agrobacterium Ti plasmid, called T-DNA, into host plant nuclear DNA. We have subjected to sequence analysis the border regions of pTi T37 (ends of T-DNA) and one left T-DNA/plant DNA border fragment isolated from BT37 tobacco teratoma by molecular cloning. These sequence studies, taken together with published sequence of a right T-DNA/plant DNA border fragment, allowed us to identify the positions of left and right borders at the DNA sequence level. Comparison of left and right border regions of the Ti plasmid revealed a "core" direct repeat of 13 of 14 bases (12 contiguous) precisely at the borders of T-DNA. An extended repeat of 21 of 25 bases overlaps this core repeat. T-DNA on the Ti plasmid exhibits no longer direct or inverted repeats in the border regions, based on Southern hybridization studies. The physical structure of T-DNA differs from that of known prokaryotic and eukaryotic transposable elements but bears a structural resemblance to the prophage of bacteriophage lambda.
根癌病是由土壤杆菌 Ti 质粒的一个片段（称为 T-DNA）插入宿主植物核 DNA 引起的。我们对 pTi T37 的边界区域（T-DNA 的末端）和通过分子克隆从 BT37 烟草畸形瘤中分离的一个左 T-DNA/植物 DNA 边界片段进行了序列分析。这些序列研究与已发表的右 T-DNA/植物 DNA 边界片段的序列一起，使我们能够在 DNA 序列水平上确定左右边界的位置。对 Ti 质粒的左右边界区域进行比较，发现 T-DNA 边界处有一个 13 个碱基（12 个连续）的“核心”直接重复序列。这个核心重复序列的扩展重复序列为 21 个碱基，重叠了 25 个碱基。基于 Southern 杂交研究，Ti 质粒上的 T-DNA 在边界区域没有更长的直接或反向重复序列。T-DNA 的物理结构与已知的原核和真核转座元件不同，但与噬菌体 lambda 的噬菌体结构相似。
