van der Woude M W, Braaten B A, Low D A
Department of Pathology, University of Utah Medical Center, Salt Lake City 84132.
Mol Microbiol. 1992 Sep;6(17):2429-35. doi: 10.1111/j.1365-2958.1992.tb01418.x.
Pyelonephritis-associated pilus (Pap) expression is regulated by a phase variation control mechanism involving PapB, Papl, catabolite activator protein (CAP), leucine-responsive regulatory protein (Lrp) and deoxyadenosine methylase (Dam). Lrp and Papl bind to a specific non-methylated pap regulatory DNA region containing the sequence 'GATC' and facilitate the formation of an active transcriptional complex. Evidence indicates that binding of Lrp and Papl to this region inhibits methylation of the GATC site by Dam. However, if this GATC site is first methylated by Dam, binding of Lrp and Papl is inhibited. These events lead to the formation of two different pap methylation states characteristic of active (ON) and inactive (OFF) pap transcription states. The fae (K88), daa (F1845) and sfa (S) pilus operons share conserved 'GATC-box' domains with pap and may be subject to a similar regulatory control mechanism involving Lrp and DNA methylation.
肾盂肾炎相关菌毛（Pap）的表达受一种相变控制机制调节，该机制涉及PapB、PapI、分解代谢物激活蛋白（CAP）、亮氨酸应答调节蛋白（Lrp）和脱氧腺苷甲基化酶（Dam）。Lrp和PapI与一个特定的未甲基化的包含序列“GATC”的pap调节性DNA区域结合，并促进活性转录复合物的形成。有证据表明，Lrp和PapI与该区域的结合会抑制Dam对GATC位点的甲基化。然而，如果这个GATC位点首先被Dam甲基化，Lrp和PapI的结合就会受到抑制。这些事件导致形成两种不同的pap甲基化状态，分别代表活跃（开启）和不活跃（关闭）的pap转录状态。Fae（K88）、Daa（F1845）和Sfa（S）菌毛操纵子与pap共享保守的“GATC盒”结构域，可能受涉及Lrp和DNA甲基化的类似调节控制机制的影响。
