Friedrich-Alexander-Universität Erlangen-Nürnberg, Lehrstuhl für Mikrobiologie, Erlangen, Germany.
J Biotechnol. 2011 Jul 10;154(2-3):156-62. doi: 10.1016/j.jbiotec.2010.09.930. Epub 2010 Sep 17.
In corynebacteria, nitrogen regulation is controlled by the TetR family protein AmtR, which was extensively studied in the last years. In frame of these studies a number of AmtR binding sites were identified and characterized and it became obvious that for distinct genes the number and sequences of these sites varied significantly. In this study, the influence of numbers and alterations of AmtR binding sites were addressed by in vivo and in vitro studies. It can be concluded that in general a single highly conserved AmtR site is sufficient for stringent regulation and that non-conserved binding sites have a very limited influence, despite the fact that binding of AmtR was shown for several of these sites, e.g. upstream of amtA, amtB and gdh. Furthermore, the reason for and consequences of the lack of AmtR autoregulation were addressed in vivo. The introduction of a spacing nucleotide between the two conserved half sites of the AmtR binding box alone is sufficient to restore AmtR autoregulation. The main differences observed between wild type and an AmtR autoregulation strain were a slightly enhanced background of transcription of AmtR-controlled genes and a slightly slower response to nitrogen limitation.
在棒状杆菌中，氮调控受 TetR 家族蛋白 AmtR 控制，近年来对其进行了广泛研究。在这些研究中，确定并描述了许多 AmtR 结合位点，并且明显的是，对于不同的基因，这些位点的数量和序列有很大差异。在这项研究中，通过体内和体外研究研究了 AmtR 结合位点数量和改变的影响。可以得出结论，通常，单个高度保守的 AmtR 位点对于严格的调控就足够了，尽管已经证明了许多这些位点（例如，amtA、amtB 和 gdh 的上游）结合了 AmtR，但非保守的结合位点的影响非常有限。此外，还在体内研究了 AmtR 自身调控缺失的原因和后果。单独在 AmtR 结合盒的两个保守半位点之间引入间隔核苷酸足以恢复 AmtR 自身调控。在野生型和 AmtR 自身调控菌株之间观察到的主要差异是 AmtR 控制的基因的转录背景略有增强，并且对氮限制的响应速度略慢。
