Targeted sigma factor turnover inserts negative control into a positive feedback loop.
Targeted sigma factor turnover inserts negative control into a positive feedback loop.
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DOI：
10.1111/j.1365-2958.2009.06823.x
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发表时间：
2009-09
影响因子：
3.6
通讯作者：
Donohue TJ
中科院分区：
文献类型：
--
作者：
Donohue TJ
自从它们被归类为σ70超家族的成员以来，第四类替代σ因子已被发现控制基因的表达，以响应不同的环境或压力信号。天蓝色链霉菌IV族成员σR(SIGR)的活性是通过改变胞质二硫键的氧化还原状态而增加的。一旦被其同源抗σ因子rsrA释放，σR就会激活基因产物的表达，帮助细胞减少胞质二硫键。在本期《分子微生物学》中，Kim和他的同事对σR活性的积极和消极控制提供了新的见解。作者发现，来自可诱导的σR依赖的sigRsrA p2启动子操纵子的转录本编码比未诱导细胞中发现的更高分子量的σR蛋白(称为σR‘)。σR‘与在未诱导细胞中发现的较小的σR蛋白的一个主要区别是，σR’被ClpP1/P2蛋白酶系统快速降解。ClpP1/ClpP2蛋白酶亚单位的基因本身就是σR调节子的成员。新发现的正向(σR‘合成)和负向控制(选择性σR’转换)方面，在其他相关的第IV组σ因子家族成员中被发现或被预测存在。
Since their classification as members of the σ70 super-family, Group IV alternative σ factors have been found to control gene expression in response to diverse environmental or stress signals. Activity of the Streptomyces coelicolor Group IV family member, σR (SigR), is increased by changes in the oxidation-reduction state of cytoplasmic disulphide bonds. Once released by its cognate anti-σ factor RsrA, σR activates expression of gene products that help cells reduce cytoplasmic disulphide bonds. In this issue of Molecular Microbiology, Kim and co-workers provide new insights into positive and negative control of σR activity. The authors show that a transcript derived from the inducible σR-dependent sigRrsrA p2 promoter operon encodes a σR protein of a higher molecular weight (termed σR′) than is found in uninduced cells. One major difference between σR′ and the smaller σR protein found in uninduced cells is the rapid proteolysis of σR′ by the ClpP1/P2 protease system. The genes for the ClpP1/ClpP2 protease subunits are themselves members of the σR regulon. The newly identified positive (σR′ synthesis) and negative control (selective σR′ turnover) aspects of this circuit are either found or predicted to exist in other related Group IV σ factor family members.
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影响因子：
12.3
作者：
Paget MS;Helmann JD
通讯作者：
Helmann JD
影响因子：
16
作者：
Campbell, Elizabeth A.;Greenwell, Roger;Darst, Seth A.
通讯作者：
Darst, Seth A.
影响因子：
5.6
作者：
Bae, JB;Park, JH;Roe, JH
通讯作者：
Roe, JH
影响因子：
3.6
作者：
Paget, MSB;Bae, JB;Buttner, MJ
通讯作者：
Buttner, MJ
DOI：
10.1006/bbrc.1995.2703
发表时间：
1995-11-22
影响因子：
3.1
作者：
SCHURR, MJ;MARTINEZSALAZAR, JM;DERETIC, V
通讯作者：
DERETIC, V