STUDIES ON MECHANISM OF REPRESSION OF ARGININE BIOSYNTHESIS IN ESCHERICHIA COLI .2. DOMINANCE OF REPRESSIBILITY IN DIPLOIDS
STUDIES ON MECHANISM OF REPRESSION OF ARGININE BIOSYNTHESIS IN ESCHERICHIA COLI .2. DOMINANCE OF REPRESSIBILITY IN DIPLOIDS
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DOI：
10.1016/s0022-2836(64)80200-x
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发表时间：
1964-01-01
影响因子：
5.6
通讯作者：
CLARK, AJ
中科院分区：
文献类型：
--
作者：
MAAS, WK;CLARK, AJ
已经分离到的菌株是二倍体的，约占大肠杆菌连锁图谱的三分之一，其中包括一个控制精氨酸生物合成酶的阻遏能力的Rarg位点。在Rarg+/Rarg-亚二倍体中，精氨酸能够抑制酶的形成，这表明在Rarg+/Rarg-亚合子中，阻滞性是一个显性性状。在解释这一发现时，有人认为Rarg+基因控制细胞质中一种特定抑制子的产生。这一解释以前在其他代谢途径中也有类似的发现，特别是乳糖发酵和组氨酸和色氨酸生物合成的酶的控制。术语调节子被用来描述这样一个系统，在这个系统中，所有酶的产生都可以由单一的阻遏物质来控制。可以区分两种类型的调节子，一种是酶的结构基因彼此相邻的(组氨酸、色氨酸)，因此由单个操纵子组成；另一种是它们不存在的(精氨酸)，因此由几个操纵子组成。
Strains have been isolated which are diploid for about one-third of the linkage map of E. coli, including a locus Rarg which controls repressibility of the enzymes of arginine biosynthesis. In Rarg+/Rarg- merodiploids, isolated from a cross of a repressible (Rarg+) double-male donor with a non-repressible (Rarg-) recipient, arginine is able to repress enzyme formation, showing that repressibility, as in Rarg+/Rarg- merozygotes, is a dominant trait. In interpreting this finding it is suggested that the gene Rarg+ controls the production of a specific repressor in the cytoplasm. This interpretation has been given previously for similar findings in other metabolic pathways, notably for the control of the enzymes of lactose fermentation and of histidine and tryptophan biosynthesis. The term regulon is proposed to describe such a system in which the production of all enzymes can be controlled by a single repressor substance. Two types of regulons can be distinguished, those in which the structural genes for the enzymes are adjacent to each other (histidine, tryptophan) and which thus consist of single operons, and those in which they are not (arginine) and which thus consist of several operons.