Novick Richard P, Geisinger Edward
Kimmel Center for Biology and Medicine, New York University Medical Center, New York, New York 10016, USA.
Annu Rev Genet. 2008;42:541-64. doi: 10.1146/annurev.genet.42.110807.091640.
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.
葡萄球菌的agr基因座编码一种群体感应（QS）系统，该系统通过经典的双组分信号模块控制毒力基因和其他辅助基因的表达。与其他革兰氏阳性细菌中的群体感应方式一样，agr编码一种自激活肽（AIP），它是agr信号受体AgrC的诱导配体。与其他此类系统不同的是，已经出现了agr变体，它们在异源组合中表现出强烈的交叉抑制，具有重要的进化意义。同样与其他系统不同的是，agr系统中全局基因调控的效应物是一种主要的调控RNA，即RNAIII。在这篇综述中，我们描述了agr系统各元件的功能，展示了它们如何相互作用以产生调控反应，并讨论了群体感应在葡萄球菌病理生物学中的作用。我们最后提出，与经典的酶诱导不同，agr自激活可以在次优条件下发生，并且可以通过诱导群体范围内排他性且协调的反应来区分自身与非自身。
