H-NS和Lrp作为大肠杆菌质粒pRK100中traJ表达的正向调节因子。
H-NS and Lrp serve as positive modulators of traJ expression from the Escherichia coli plasmid pRK100.
作者信息
Starcic-Erjavec M, van Putten J P M, Gaastra W, Jordi B J A M, Grabnar M, Zgur-Bertok D
机构信息
Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, 1000 Ljubljana, Slovenia.
出版信息
Mol Genet Genomics. 2003 Oct;270(1):94-102. doi: 10.1007/s00438-003-0908-1. Epub 2003 Aug 26.
Conjugative transfer of F-like plasmids is a tightly regulated process. The TraJ protein is the main positive activator of the tra operon which encodes products required for conjugative transfer of F-like plasmids. Nucleotide sequence analysis revealed potential Lrp and H-NS binding sites in the traJ regulatory region. Expression of a traJ-lacZ fusion in hns and lrp mutant strains showed that both are positive modulators of traJ expression. Competitive RT-PCR demonstrated that H-NS and Lrp exert their effect at the transcriptional level. Electrophoretic mobility-shift assays showed that H-NS and Lrp proteins bind to the traJ promoter. Conjugative transfer of pRK100 was decreased in hns but not in lrp mutant strains. Together, the results indicate H-NS and Lrp function as activators of traJ transcription.
F 类质粒的接合转移是一个受到严格调控的过程。TraJ 蛋白是 tra 操纵子的主要正激活因子，该操纵子编码 F 类质粒接合转移所需的产物。核苷酸序列分析揭示了 traJ 调控区域中潜在的 Lrp 和 H-NS 结合位点。在 hns 和 lrp 突变株中 traJ-lacZ 融合蛋白的表达表明，二者都是 traJ 表达的正调控因子。竞争性 RT-PCR 证明 H-NS 和 Lrp 在转录水平发挥作用。电泳迁移率变动分析表明 H-NS 和 Lrp 蛋白与 traJ 启动子结合。在 hns 突变株中 pRK100 的接合转移减少，但在 lrp 突变株中未减少。总之，结果表明 H-NS 和 Lrp 作为 traJ 转录的激活因子发挥作用。
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