Glucose uptake pathway-specific regulation of synthesis of neotrehalosadiamine, a novel autoinducer produced in Bacillus subtilis
Glucose uptake pathway-specific regulation of synthesis of neotrehalosadiamine, a novel autoinducer produced in Bacillus subtilis
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DOI：
10.1128/jb.01478-06
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发表时间：
2007-01-01
影响因子：
3.2
通讯作者：
Ochi, Kozo
中科院分区：
文献类型：
--
作者：
Inaoka, Takashi;Ochi, Kozo
新海藻糖二胺（3，3 '-二氨基-3，3'-双脱氧-α，β-海藻糖; NTD）是一种氨基糖抗生素，由几种芽孢杆菌产生，通过激活其自身的生物合成操纵子ntdABC作为自诱导物发挥作用。我们以前报道过，将特定的rpoB突变（rpoB 5）引入枯草芽孢杆菌，使细胞过量生产NTD。B。枯草杆菌mini-Tn 10转座文库中筛选了影响NTD生产的基因。失活的cepA，它编码一个主要的转录调节碳代谢产物的监管，显着减少NTD的生产。相比之下，失活glcP，这是位于下游的ntdABC和编码的葡萄糖/甘露糖：H+同向转运通透酶，刺激NTD生产。glcP的过表达导致响应于GlcP介导的葡萄糖摄取的ntdABC表达（和因此NTD产生）的抑制。这些结果表明，CepA介导的ntdABC表达的分解代谢物激活响应于经由葡萄糖-6-磷酸的果糖-1，6-二磷酸的体内浓度的增加而发生，并且GlcP介导的ntdABC表达的葡萄糖抑制与未磷酸化葡萄糖的体内浓度的增加相关联而发生。此外，北方分析表明glcP通过在ntdABC转录终止子位点的转录通读从ntdABC启动子转录，这使得NTD能够通过刺激ntdABC-glcP转录作为葡萄糖摄取的调节剂发挥作用，即使在野生型（rpoB（+））细胞中。微量（0.5至3 μ g/ml）的NTD足以确保glcP的表达，从而证明了“抗生素”在生产细菌中通过作为葡萄糖摄取调节的自诱导物而发挥的生理作用。
Neotrehalosadiamine (3,3'-diamino-3,3'-dideoxy-alpha,beta-trehalose; NTD) is an amino-sugar antibiotic produced by several Bacillus species that functions as an autoinducer by activating its own biosynthetic operon, ntdABC. We previously reported that the introduction of a certain rpoB mutation (rpoB5) into Bacillus subtilis enables the cells to overproduce NTD. B. subtilis mini-Tn10 transposant libraries have been screened for genes that affect NTD production. Inactivation of cepA, which encodes a major transcriptional regulator of carbon catabolite regulation, markedly reduced NTD production. By contrast, inactivation of glcP, which is situated just downstream of ntdABC and encodes a glucose/mannose:H+ symport permease, stimulated NTD production. Overexpression of glcP led to the repression of ntdABC expression (and thus NTD production) in response to GlcP-mediated glucose uptake. These results suggest that CepA-mediated catabolite activation of ntdABC expression occurs in response to the increase of the in vivo concentration of fructose-1,6-bisphosphate via glucose-6-phosphate and that GlcP-mediated glucose repression of ntdABC expression occurs in association with the increase of the in vivo concentration of unphosphorylated glucose. In addition, Northern analysis showed that glcP is transcribed from the ntdABC promoter through transcription readthrough at the ntdABC transcription terminator site, which enables NTD to function as a modulator of glucose uptake through the stimulation of ntdABC-glcP transcription, even in wild-type (rpoB(+)) cells. A trace amount (0.5 to 3 mu g/ml) of NTD was sufficient to ensure expression of glcP, thus demonstrating the physiological role of "antibiotic" in the producing bacteria by functioning as an autoinducer for glucose uptake modulation.