Zuber M, Hoover T A, Powell B S, Court D L
Toxinology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702-5011.
Mol Microbiol. 1994 Oct;14(2):291-300. doi: 10.1111/j.1365-2958.1994.tb01290.x.
A 3.2 kb EcoRI genomic DNA fragment of Coxiella burnetii was isolated by virtue of its ability to suppress mucoidy in Escherichia coli. Nucleotide sequence analysis revealed the presence of the genes homologous to rnc, era and recO of E. coli. Suppression of capsule synthesis, measured by beta-galactosidase expression in lon- cps-lac fusion strains of E. coli, is caused by gene-dosage effects of the plasmid-borne rnc genes of either C. burnetii or E. coli. The rnc gene of C. burnetii complemented rnc- E. coli hosts for lambda plaque morphology and stimulation of lambda N gene expression. We also demonstrated heterologous complementation of an E. coli strain defective for the expression of Era, an essential protein in E. coli, using the plasmid-borne C. burnetii era. Under the control of the bacteriophage lambda PL promoter, this 3.2 kb EcoRI DNA fragment directed the synthesis in E. coli of three proteins with approximate molecular masses of 35, 27 and 25 kDa. Antibodies against purified E. coli Era protein cross-reacted with the 35 kDa protein of C. burnetii on Western blots.
通过其抑制大肠杆菌黏液形成的能力，分离出了3.2 kb的伯氏考克斯氏体EcoRI基因组DNA片段。核苷酸序列分析显示存在与大肠杆菌的rnc、era和recO同源的基因。在大肠杆菌lon-cps-lac融合菌株中通过β-半乳糖苷酶表达来衡量的荚膜合成抑制，是由伯氏考克斯氏体或大肠杆菌质粒携带的rnc基因的基因剂量效应引起的。伯氏考克斯氏体的rnc基因在λ噬菌斑形态和刺激λ N基因表达方面补充了rnc -大肠杆菌宿主。我们还证明了使用质粒携带的伯氏考克斯氏体era对大肠杆菌中一种因Era表达缺陷而有缺陷的菌株进行异源互补，Era是大肠杆菌中的一种必需蛋白。在噬菌体λ PL启动子的控制下，这个3.2 kb的EcoRI DNA片段指导大肠杆菌中合成了三种分子量约为35、27和25 kDa的蛋白质。在蛋白质免疫印迹中，针对纯化的大肠杆菌Era蛋白的抗体与伯氏考克斯氏体的35 kDa蛋白发生交叉反应。
