THE AGR P2 OPERON - AN AUTOCATALYTIC SENSORY TRANSDUCTION SYSTEM IN STAPHYLOCOCCUS-AUREUS
THE AGR P2 OPERON - AN AUTOCATALYTIC SENSORY TRANSDUCTION SYSTEM IN STAPHYLOCOCCUS-AUREUS
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DOI：
10.1007/bf02191645
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发表时间：
1995-08-30
期刊：
影响因子：
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通讯作者：
MOGHAZEH, S
中科院分区：
文献类型：
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作者：
NOVICK, RP;PROJAN, SJ;MOGHAZEH, S
金黄色葡萄球菌中毒力因子和其他外蛋白的合成由全局调节因子agr控制。分泌蛋白的表达在指数后生长期被上调，而表面蛋白的表达被agr下调。agr基因座由两个不同的操纵子组成，从相邻但不重叠的启动子P2和P3转录。本文报道的P2操纵子序列包含4个开放阅读框，agr A、C、D和B，其中A和C似乎编码经典的2组分信号转导途径的蛋白质。P3操纵子指定一个0.5 kb的转录本，RNA III，它是agr反应的实际效应子，顺便说一句，编码agr调节的肽δ-溶血素。转录融合显示P2和P3都是agr敏感的（在agr（+）背景中起作用，但在agr（-）背景中不起作用），缺失分析显示所有四个P2 ORF都参与其中; agrA和agrC似乎是agr基因座转录激活所绝对需要的，而agrB和agrD似乎是部分需要的。由于P2的转录需要P2操纵子产物，因此P2操纵子是自催化的，并且因此令人钦佩地适合于在整体生长即将停止时快速产生外蛋白的需要。
The synthesis of virulence factors and other exoproteins in Staphylococcus aureus is controlled by the global regulator, agr. Expression of secreted proteins is up-regulated in the postexponential growth phase, whereas expression of surface proteins is down-regulated by agr. The agr locus consists of two divergent operons, transcribed from neighboring but non-overlapping promoters, P2 and P3. The P2 operon sequence, reported here, contains 4 open reading frames, agr A, C, D, and B, of which A and C appear to encode proteins of a classical 2-component signal transduction pathway. The P3 operon specifies a 0.5 kb transcript, RNA III, which is the actual effector of the agr response, and, incidentally, encodes the agr-regulated peptide delta-hemolysin. Transcriptional fusions have shown that both P2 and P3 are agr sensitive (function in an agr(+) but not in an agr(-) back-ground) and deletion analysis has shown that all four of the P2 ORFs are involved; agrA and agrC seem to be absolutely required for the transcriptional activation of the agr locus, whereas agrB and agrD seem to be partially required. Since transcription of P2 requires P2 operon products, the P2 operon is autocatalytic, and is thus admirably suited to the need for rapid production of exoproteins at a time when overall growth is coming to a halt.