The staphylococcal agr locus encodes a quorum sensing (QS) system that controls the expression of virulence and other accessory genes by a classical two-component signaling module. Like QS modalities in other Gram-positive bacteria, agr encodes an autoactivating peptide (AIP) that is the inducing ligand for AgrC, the agr signal receptor. Unlike other such systems, agr variants have arisen that show strong cross-inhibition in heterologous combinations, with important evolutionary implications. Also unlike other systems, the effector of global gene regulation in the agr system is a major regulatory RNA, RNAIII. In this review, we describe the functions of the agr system's elements, show how they interact to bring about the regulatory response, and discuss the role of QS in staphylococcal pathobiology. We conclude with the suggestion that agr autoactivation, unlike classical enzyme induction, can occur under suboptimal conditions and can distinguish self from non-self by inducing an exclusive and coordinated population wide response.

中文翻译：

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法定人数在葡萄球菌。

葡萄球菌的农业基因座编码一个群体感应（QS）系统，该系统通过经典的两组分信号传导模块控制毒力和其他辅助基因的表达。像其他革兰氏阳性细菌中的QS模式一样，agr编码自激活肽（AIP），它是agrC（agr信号受体）的诱导配体。与其他此类系统不同，已经出现了agr变体，它们在异源组合中表现出强大的交叉抑制作用，具有重要的进化意义。同样与其他系统不同，在agr系统中全局基因调控的影响因子是主要的调控RNA RNAIII。在这篇综述中，我们描述了agr系统元素的功能，展示了它们如何相互作用以引起调节反应，并讨论了QS在葡萄球菌病理生物学中的作用。