ZntR-mediated transcription of zntA responds to nanomolar intracellular free zinc.
ZntR-mediated transcription of zntA responds to nanomolar intracellular free zinc.
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DOI：
10.1016/j.jinorgbio.2012.02.008
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发表时间：
2012-06
影响因子：
3.9
通讯作者：
Fierke, Carol A.
中科院分区：
文献类型：
--
作者：
Wang, Da;Hosteen, Olijahwon;Fierke, Carol A.
In E. coli, ZitB and ZntA are important metal exporters that enhance cell viability under high environmental zinc. To understand their functions in maintaining zinc homeostasis, we applied a novel genetically-encoded fluorescent zinc sensor to monitor the intracellular free zinc changes in wild type, ΔzitB and ΔzntA E. coli cells upon sudden exposure to toxic levels of zinc (“zinc shock”). The intracellular readily exchangeable zinc concentration (or “free” zinc) increases transiently from picomolar to nanomolar levels, accelerating zinc-activated gene transcription. After zinc shock, the zitB mRNA level is constant while the zntA mRNA increases substantially in a zinc-dependent manner. In the ΔzitB E. coli strain the free zinc concentration rises more rapidly after zinc shock compared to wild-type cells while a prolonged accumulation of free zinc is observed in the ΔzntA strain. Based on these results, we propose that ZitB functions as a constitutive, first-line defense against toxic zinc influx, while ZntA is up-regulated to efficiently lower the free zinc concentration. Furthermore, the ZntR-mediated transcription of zntA exhibits an apparent K1/2 for zinc activation in the nanomolar range in vivo, significantly higher than the femtomolar affinity for zinc binding and transcription activation previously measured in vitro. A kinetically-controlled transcription model is sufficient to explain the observed regulation of intracellular free zinc concentration by ZntR and ZntA after zinc shock.
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影响因子：
7.1
作者：
FOSMIRE, GJ
通讯作者：
FOSMIRE, GJ
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
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DOI：
10.1073/pnas.96.5.1936
发表时间：
1999-03-02
影响因子：
11.1
作者：
Maret, W;Jacob, C;Fischer, EH
通讯作者：
Fischer, EH
影响因子：
3.2
作者：
Grass, G;Fan, B;Rensing, C
通讯作者：
Rensing, C
影响因子：
3.2
作者：
Grass, G;Wong, MD;Rensing, C
通讯作者：
Rensing, C