Dunny G M, Antiporta M H, Hirt H
Department of Microbiology, University of Minnesota Medical School, 1460 Mayo Bldg, 420 Delaware St. SE, Minneapolis, MN 55455-0312, USA.
Peptides. 2001 Oct;22(10):1529-39. doi: 10.1016/s0196-9781(01)00489-2.
The tetracycline resistance plasmid pCF10 represents a class of unique mobile genetic elements of the bacterial genus Enterococcus, whose conjugative transfer functions are inducible by peptide sex pheromones excreted by potential recipient cells. These plasmids play a significant role in the dissemination of virulence and antibiotic resistance genes among the enterococci, which have become major nosocomial pathogens. Pheromone response by plasmid-carrying donor cells involves specific import of the peptide signal molecule, and subsequent interaction of the signal with one or more intracellular regulatory gene products. The pheromones are chromosomally encoded hydrophobic octa- or hepta-peptides, and different families of homologous plasmids encode the ability to respond to each pheromone. Among the four pheromone-responsive plasmids that have been characterized in some detail, there is considerable conservation in the genes encoding pheromone sensing and regulatory functions, and the peptides themselves show considerable similarity. In spite of this, there is extremely high specificity of response to each peptide, with virtually no "cross-induction" of transfer of non-cognate pheromone plasmids by the pheromones. This communication reviews the evidence for this specificity and discusses current molecular and genetic approaches to defining the basis for specificity.
四环素抗性质粒pCF10代表了肠球菌属一类独特的可移动遗传元件，其接合转移功能可被潜在受体细胞分泌的肽性信息素诱导。这些质粒在肠球菌间毒力和抗生素抗性基因的传播中发挥着重要作用，而肠球菌已成为主要的医院病原体。携带质粒的供体细胞对信息素的反应涉及肽信号分子的特异性导入，以及信号与一种或多种细胞内调节基因产物的后续相互作用。信息素是由染色体编码的疏水八肽或七肽，不同家族的同源质粒编码对每种信息素的反应能力。在已得到一定详细表征的四种对信息素反应的质粒中，编码信息素感应和调节功能的基因有相当程度的保守性，并且这些肽本身也显示出相当大的相似性。尽管如此，对每种肽的反应仍具有极高的特异性，几乎不存在非同源信息素质粒的转移被信息素“交叉诱导”的情况。本通讯综述了这种特异性的证据，并讨论了当前用于确定特异性基础的分子和遗传方法。
