von Lintig J, Zanker H, Schröder J
Universität Freiburg, Institut für Biologie II, Freiburg, Federal Republic of Germany.
Mol Plant Microbe Interact. 1991 Jul-Aug;4(4):370-8. doi: 10.1094/mpmi-4-370.
The noc and occ regions of nopaline and octopine Ti plasmids in Agrobacterium tumefaciens contain genes for the catabolism of nopaline and octopine, respectively. We investigated the transcriptional organization and regulation of both regions. The noc region of pTiC58 contains two nopaline-inducible promoters, and one octopine-inducible promoter was identified in the occ region of pTiAch5. All three promoters are positively regulated in trans by constitutively expressed genes localized at the right end of the regions. The DNA sequence analysis of these parts revealed genes coding for related proteins (35.6% identity). The two polypeptides share significant similarity with a family of other positive gene regulators, and both contain a protein motif ("LysR" signature) that is characteristic for the DNA binding domain in these polypeptides. These proteins are the only Ti plasmid functions necessary for the activation of the opine-induced promoters. We propose the names nocR and occR for the regulator genes in the noc and in the occ regions.
根癌土壤杆菌中胭脂碱型和章鱼碱型Ti质粒的noc和occ区域分别包含胭脂碱和章鱼碱分解代谢的基因。我们研究了这两个区域的转录组织和调控。pTiC58的noc区域包含两个胭脂碱诱导型启动子，并且在pTiAch5的occ区域鉴定出一个章鱼碱诱导型启动子。所有这三个启动子都由位于这些区域右端的组成型表达基因进行反式正调控。对这些区域的DNA序列分析揭示了编码相关蛋白的基因（同一性为35.6%）。这两种多肽与其他正基因调控因子家族具有显著相似性，并且都含有一个蛋白质基序（“LysR”特征），该基序是这些多肽中DNA结合结构域的特征。这些蛋白是激活冠瘿碱诱导型启动子所需的唯一Ti质粒功能。我们提议将noc区域和occ区域中的调控基因分别命名为nocR和occR。
