Molecular Mechanism of Glucose Effect in E.coli.

大肠杆菌中葡萄糖效应的分子机制。

• 批准号: 04454607
• 负责人: AIBA Hiroji
• 金额: $ 0.7万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04454607/
• 关键词: glucose repression; catabolite repression; cAMP; CRP; autoregulation; crp gene; lactose operon; Escherichis coli; グルコース効果; 転写調節; 正の自己制御機構

It was found that glucose lowers the amount of cAMP receptor protein(CRP)inEscherichia coli cells. A correlation exists between CRP and b-galactosidase levels in cells growing under various conditions. When the CRP concentration is reduced by manipulating the crp gene, the b-galactosidase expression decreases in proportion to the concentration of CRP.These findings indicate that the lowered concentration of CRP caused by glucose is one of major factors for catabolite repression. We propose that glucose causes catabolite repression by lowering the intracellular levels of both CRP and cAMP.The molecular mechanism underlying the down-regulation of CRP by glucose was investigated. Replacement of the crp promoter to the bla promoter abolishes mostly the glucose-mediated regulation of crp expression. The disruption of the CRP-binding site II essentially eliminates the down-regulation of the crp expression by glucose. It was concluded that the autoregulatory circuit of the crp gene plays a key role in the down-regulation of CRP by glucose.

研究发现，葡萄糖会降低大肠杆菌细胞中cAMP受体蛋白（CRP）的量。在不同条件下生长的细胞中，CRP 和 β-半乳糖苷酶水平之间存在相关性。当通过操纵crp基因降低CRP浓度时，β-半乳糖苷酶表达与CRP浓度成比例地降低。这些发现表明，葡萄糖引起的CRP浓度降低是分解代谢物抑制的主要因素之一。我们提出葡萄糖通过降低细胞内CRP和cAMP水平来抑制分解代谢物。研究了葡萄糖下调CRP的分子机制。将 crp 启动子替换为 bla 启动子基本上消除了葡萄糖介导的 crp 表达调节。 CRP 结合位点 II 的破坏基本上消除了葡萄糖对 crp 表达的下调。结论：crp基因的自动调节回路在葡萄糖下调CRP的过程中起关键作用。

项目成果

饗場弘二: "A lowered concentration of CAMP receptor protein…" Mol.Microbiol.10. 341-350 (1993)

Koji Yaba：“CAMP 受体蛋白浓度降低……”Mol.Microbiol.10 (1993)。

饗場弘二: "転写活性化蛋白質とRNAポリメラーゼの相互作用" 生物物理. 33. 148-153 (1993)

Koji Yoba：“转录激活蛋白和 RNA 聚合酶之间的相互作用”生物物理学 33. 148-153 (1993)。

Aiba, H: "Anew aspect of transcriptional control of the Echerichia coli crp gene : positive autoregulation" Mol.Microbiol.6. 2489-2497 (1992)

Aiba, H：“大肠杆菌 crp 基因转录控制的新方面：正向自动调节”Mol.Microbiol.6。

Aiba, H.: "Mechanism of the down-regulation of cAMP receptor protein by glucose in Escherichia coli : role of autoregulation of the crp gene" EMBO J.13. 3077-3082

Aiba, H.：“大肠杆菌中葡萄糖下调 cAMP 受体蛋白的机制：crp 基因自动调节的作用”EMBO J.13。

Akemi Hanamura: "A new aspect of transcriptional control of the Escherichia coli crp gene:positive autoregulation" Molecular Microbiology. 6. 2489-2497 (1992)

Akemi Hanamura：“大肠杆菌 crp 基因转录控制的新方面：正向自动调节”分子微生物学。