锌
同色链霉菌
基因
锌指
生物
基因表达调控
化学
生物化学
突变体
转录因子
有机化学
作者
Seung Hwan Choi,Kang-Lok Lee,Jung-Ho Shin,Yoo-Bok Cho,Sun‐Shin Cha,Jung-Hye Roe
摘要
Abstract In most bacteria, zinc depletion is sensed by Zur, whereas the surplus is sensed by different regulators to achieve zinc homeostasis. Here we present evidence that zinc-bound Zur not only represses genes for zinc acquisition but also induces the zitB gene encoding a zinc exporter in Streptomyces coelicolor , a model actinobacteria. Zinc-dependent gene regulation by Zur occurs in two phases. At sub-femtomolar zinc concentrations (phase I), dimeric Zur binds to the Zur-box motif immediately upstream of the zitB promoter, resulting in low zitB expression. At the same time, Zur represses genes for zinc uptake. At micromolar zinc concentrations (phase II), oligomeric Zur binding with footprint expansion upward from the Zur box results in high zitB induction. Our findings reveal a mode of zinc-dependent gene activation that uses a single metalloregulator to control genes for both uptake and export over a wide range of zinc concentrations.
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