Genetic Functions of an Enterococcal R Factor

肠球菌 R 因子的遗传功能

• 批准号: 6712122
• 负责人: GARY M DUNNY
• 金额: $ 25.65万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 2005-12-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6712122
• 关键词: Enterococcus; R factors; bacterial genetics; binding proteins; drug resistance; gene expression; laboratory mouse; laboratory rabbit; microorganism conjugation; pheromone; plasmids

DESCRIPTION (Verbatim from Applicant's Abstract): The enterococci have become prevalent as causes of nosocomial infections. The high incidence of resistance of these organisms to the most efficacious antibiotics (e.g., vancomycin) causes major problems in treating enterococcal infections, and the tremendous reservoir of enterococcal resistance determinants serves as a vector for the spread of these genes to other, more pathogenic bacterial genera. This research is focused on dissection of a mechanism of horizontal genetic transfer of the antibiotic resistance plasmid pCF10 in Enterococcus faecalis. The most novel feature of this transfer system is that the pCF10-containing donor cell perceives the presence of potential recipients in its vicinity by sensing a small peptide signal (a sex pheromone called cCF10) excreted by the recipients. The donor cell only expresses genes required for plasmid transfer when exogenous cCF10 is detected in the growth medium. Both the donor cells response to exogenous pheromone, and the negative control system that prevents expression of transfer functions in the absence of exogenous pheromone, are complex processes that have been studied in detail. Enterococci produce a variety of peptide pheromones, consisting of hydrophobic peptides 7-8 amino acids in length. Different families of plasmids each encode a highly specific response to a single cognate pheromone. When a single cell carrying multiple pheromone plasmids is exposed to one pheromone, only the corresponding plasmid is transferred, even though the sensing systems are quite similar for all the plasmids examined to date. In the next funding period, the focus of the experiments will be on the molecular and genetic basis for the specificity of the pheromone response. The specific aims are: 1) Determine the molecular basis for specificity of pheromone cCF10 interactions with PrgZ (the extracellular pCF10-encoded pheromone binding protein), and with PrgX (the putative intracellular receptor for cCF10 believed to comprise the molecular switch involved in the intracellular phase of pheromone induction. 2) Determine the molecular basis for specific abolition of endogenous cCF10 activity in pCF10-containing donor cells by PrgY (a pCF10-encoded membrane protein), and by iCF10 (a plasmid-encoded peptide inhibitor of cCF10). 3) Determine the molecular basis for the activity and specificity of a novel regulatory RNA, Qa in blocking expression of conjugation in uninduced cells via its interaction with PrgX and with the Qs RNA encoded in the positive control region of pCF10. 4) Begin an experimental analysis of the genetic and molecular basis for specificity of the downstream steps in pheromone induction. These steps include post-transcriptional activation of transfer gene expression, and conjugative DNA processing.

描述（摘自申请人摘要）：肠球菌已经成为

项目成果

Monoclonal antibodies to cell surface antigens involved in sex pheromone induced mating in Streptococcus faecalis.

针对参与粪链球菌性信息素诱导交配的细胞表面抗原的单克隆抗体。

• DOI: 10.1099/00221287-132-4-857
• 发表时间: 1986
• 期刊: Journal of general microbiology
• 作者: Tortorello,M;Adsit,J;Krug,D;Antczak,D;Dunny,G
• 通讯作者: Dunny,G

Identification of multiple cell surface antigens associated with the sex pheromone response of Streptococcus faecalis.

与粪链球菌性信息素反应相关的多种细胞表面抗原的鉴定。

• DOI: 10.1128/jb.162.1.131-137.1985
• 发表时间: 1985
• 期刊: Journal of bacteriology
• 影响因子: 3.2
• 作者: Tortorello,ML;Dunny,GM
• 通讯作者: Dunny,GM

Genetic functions and cell-cell interactions in the pheromone-inducible plasmid transfer system of Enterococcus faecalis.

粪肠球菌信息素诱导质粒转移系统中的遗传功能和细胞间相互作用。

• DOI: 10.1111/j.1365-2958.1990.tb00639.x
• 发表时间: 1990
• 期刊: Molecular microbiology
• 影响因子: 3.6
• 作者: Dunny,GM

Structure of cCF10, a peptide sex pheromone which induces conjugative transfer of the Streptococcus faecalis tetracycline resistance plasmid, pCF10.

cCF10 的结构，一种肽性信息素，可诱导粪链球菌四环素抗性质粒 pCF10 的接合转移。

• 发表时间: 1988
• 期刊: The Journal of biological chemistry
• 作者: Mori,M;Sakagami,Y;Ishii,Y;Isogai,A;Kitada,C;Fujino,M;Adsit,JC;Dunny,GM;Suzuki,A
• 通讯作者: Suzuki,A

Cis-acting, orientation-dependent, positive control system activates pheromone-inducible conjugation functions at distances greater than 10 kilobases upstream from its target in Enterococcus faecalis.

顺式作用、方向依赖性、正控制系统在粪肠球菌中距目标上游 10 kb 以上的距离处激活信息素诱导的缀合功能。

• DOI: 10.1073/pnas.89.19.9020
• 发表时间: 1992
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Chung,JW;Dunny,GM
• 通讯作者: Dunny,GM