| 论文题目: | Importance and regulation of inositol biosynthesis during growth and differentiation of Streptomyces |
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| 作者: | Zhang, GH; Tian, YQ; Hu, K; Zhu, Y; Chater, KF; Feng, C; Liu, G; Tan, HR |
| 联系作者: | Tan, HR |
| 刊物名称: | MOLECULAR MICROBIOLOGY |
| 期: | 6 |
| 卷: | 83 |
| 页: | 1178-1194 |
| 年份: | 2012 |
| 影响因子: | 5.01 |
| 论文下载: | |
| 摘要: | Unusually among bacteria, actinobacteria possess myo-inositol 1-phosphate synthase (mIPS). In the developmentally complex Streptomyces coelicolor, the mIPS-encoding gene (inoA) is cotranscribed with a putative regulatory gene (inoR). The inoRA transcript was more abundant in an inoR in-frame deletion mutant, and InoR formed different complexes in vitro with an extensive region around the inoRA promoter. Binding was relieved by adding glucose 6-phosphate. Thus, InoR is a metabolite-sensitive autorepressor that influences inoA expression, and hence the level of inositol, by controlling transcription from PinoRA. Disruption of inoA resulted in inositol-dependent growth and development, with full phenotypic correction at 0.1 mM inositol: at lower inositol concentrations differentiation was arrested at intermediate stages. This pattern may partly reflect increased demand for membrane phospholipids during sporulation septation. A corresponding sharp upregulation of inoRA transcription coincident with sporulation was dependent on a developmental regulator, WhiI. A truncated form of WhiI could bind two sites downstream of PinoRA, and one of the WhiI-binding sites overlapped the InoR-binding site. The combined action of a metabolic regulator and a developmental regulator at the simple PinoRA promoter is a previously undescribed strategy for the differential provision of developmentally appropriate levels of a substance required during the formation of spore chains. |
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