Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, China.
Mol Biol Rep. 2010 Jun;37(5):2157-62. doi: 10.1007/s11033-009-9688-y. Epub 2009 Aug 9.
Agrobacterium tumefaciens transfers DNA from its Ti plasmid to plant host cells. The genes located within the transferred DNA of Ti plasmid including the octopine synthase gene (OCS) are expressed in plant host cells. The 3'-flanking region of OCS gene, known as OCS terminator, is widely used as a transcriptional terminator of the transgenes in plant expression vectors. In this study, we found the reversed OCS terminator (3'-OCS-r) could drive expression of hygromycin phosphotransferase II gene (hpt II) and beta-glucuronidase gene in Escherichia coli, and expression of hpt II in A. tumefaciens. Furthermore, reverse transcription-polymerase chain reaction analysis revealed that an open reading frame (ORF12) that is located downstream to the 3'-OCS-r was transcribed in A. tumefaciens, which overlaps in reverse with the coding region of the OCS gene in octopine Ti plasmid.
根癌农杆菌将其 Ti 质粒中的 DNA 转移至植物宿主细胞。Ti 质粒中转录的 DNA 中包含的基因，包括章鱼碱合酶基因（OCS），在植物宿主细胞中表达。OCS 基因的 3' 侧翼区，称为 OCS 终止子，被广泛用作植物表达载体中转基因的转录终止子。在本研究中，我们发现反转 OCS 终止子（3'-OCS-r）可以在大肠杆菌中驱动潮霉素磷酸转移酶 II 基因（hpt II）和β-葡萄糖醛酸酶基因的表达，以及在根癌农杆菌中 hpt II 的表达。此外，反转录-聚合酶链反应分析显示，位于 3'-OCS-r 下游的一个开放阅读框（ORF12）在根癌农杆菌中被转录，该 ORF12 与章鱼碱 Ti 质粒中 OCS 基因的编码区反向重叠。
