POSITIVE AND NEGATIVE REGULATORS FOR GLUCITOL (GUT) OPERON EXPRESSION IN ESCHERICHIA-COLI
POSITIVE AND NEGATIVE REGULATORS FOR GLUCITOL (GUT) OPERON EXPRESSION IN ESCHERICHIA-COLI
复制标题
DOI：
10.1016/0022-2836(88)90193-3
复制
发表时间：
1988-10-05
影响因子：
5.6
通讯作者：
SAIER, MH
中科院分区：
文献类型：
--
作者：
YAMADA, M;SAIER, MH
大肠杆菌中葡萄糖醇（gut）操纵子的表达受一个不寻常的复杂系统调节，该系统除cAMP-CRP复合物（CRP，cAMP受体蛋白）外，还包括一个激活子（由gutM基因编码）和一个阻遏子（由gutR基因编码）。根据其结构基因的核苷酸序列推断，激活子和阻遏子分别具有119（Mr = 12，955）和257（Mr = 28，240）个氨酰基残基。编码这两种调节因子的基因都位于其他已知肠道结构基因的下游。逆转录酶图谱显示，gutM基因是一个启动子远端组成的肠道操纵子。gutR基因有其自身的启动子，但该基因的表达主要是由于来自肠操纵子-启动子的通读。因此，肠道操纵子由至少五个结构基因组成，并具有以下基因顺序：gutOPABDMR。有趣的是，起始于gutR基因特异性启动子的mRNA合成发生在gutM基因内。肠操纵子的表达控制似乎是由于自体调节的gutM和gutR基因的产物的拮抗作用而发生的。一个额外的顺反子的肠道操纵子，未知的功能，可能遵循gutR基因。
Expression of the glucitol (gut) operon in Escherichia coli is regulated by an unusual, complex system which consists of an activator (encoded by the gutM gene) and a repressor (encoded by the gutR gene) in addition to the cAMP-CRP complex (CRP, cAMP receptor protein). The activator and repressor are predicted to possess 119 (Mr = 12,955) and 257 (Mr = 28,240) aminoacyl residues, respectively, as deduced from the nucleotide sequences of their structural genes. Both of the genes encoding the two regulators are located downstream from the other known gut structural genes. Reverse transcriptase mapping revealed that the gutM gene is a promoter-distal constituent of the gut operon. The gutR gene has its own promoter, but expression of this gene is primarily due to readthrough from the gut operon operator-promoter. Thus, the gut operon consists of at least five structural genes and has the following gene order: gutOPABDMR. Interestingly, synthesis of the mRNA, which initiates at the promotor specific to the gutR gene, occurs within the gutM gene. Expressional control of the gut operon appears to occur as a consequence of the antagonistic action of the products of the autogenously regulated gutM and gutR genes. An additional cistron of the gut operon, of unknown fuction, may follow the gutR gene.