Physiological control of Mu-dependent DNA arrangements

阿拉伯- lacz杂交编码序列的形成通常利用转座噬菌体Mu的DNA重排活性。融合事件是生理特异性的：它们不会在正常生长期间发生，但在饥饿后发生率很高。这个系统是现在被称为“定向突变”的可诱导基因变化的一个主要例子。我们已经开发了一个详细的分子解释的复杂的生化事件系列，产生阿拉木图融合。cAMP-CRP分解代谢感觉系统和CLP热休克蛋白酶在饥饿状态下的Mu激活中起重要作用。PCR技术已被证实用于检测罕见的融合事件，并且有证据表明应激后无融合重排。因此，ara- lac融合系统是最具特征的生理调控突变系统之一。本文概述了遗传学研究和分子实验，以确定cAMP-CRP和CLP系统在Mu激活中的作用，确定融合形成的其他生化途径，并阐明应激后Mu依赖性DNA重排的本质。这项研究的结果将为定向突变争议中的几个问题提供明确的答案，并确定连接细胞生理学和DNA生物化学的信号转导网络的组成部分。

Formation of araB-lacZ hybrid coding sequences normally utilizes the DNA rearrangement activities of transposable bacteriophage Mu. Fusion events are physiologically specific: they do not occur during normal growth but are found at high rates following starvation. This system is a prime example of inducible genetic changes now called "directed mutation." We have developed a detailed molecular explanation of the complex series of biochemical events that produce ara-lac fusions. The cAMP-CRP catabolite sensory system and the CLP heat-shock protease play essential roles in Mu activation during starvation. PCR technology has been validated for the detection of rare fusion events, and there is evidence for no-fusion rearrangements after stress. Thus, the ara- lac fusion system is one of the best-characterized physiologically regulated mutational systems. Genetic studies and molecular experiments are outlined here to define the roles of the cAMP-CRP and CLP systems in Mu activation, to identify alternative biochemical pathways to fusion formation, and to clarify the nature of Mu-dependent DNA rearrangements following stress. %%% The results of this research will provide definitive answers to several issues in the directed mutation controversy and identify components of the signal transduction network connecting cellular physiology and DNA biochemistry.