The trp RNA-binding attenuation protein of Bacillus subtilis regulates translation of the tryptophan transport gene trpP (yhaG) by blocking ribosome binding.
The trp RNA-binding attenuation protein of Bacillus subtilis regulates translation of the tryptophan transport gene trpP (yhaG) by blocking ribosome binding.
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枯草芽孢杆菌的 trp RNA 结合减弱蛋白通过阻断核糖体结合来调节色氨酸转运基因 trpP (yhaG) 的翻译。
DOI：
10.1128/jb.186.2.278-286.2004
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发表时间：
2004
影响因子：
3.2
通讯作者：
Babitzke,Paul
中科院分区：
文献类型：
--
作者：
Yakhnin,Helen;Zhang,Hong;Yakhnin,AlexanderV;Babitzke,Paul
枯草杆菌色氨酸生物合成基因（trpEDCBA和pabA [trpG]）的表达受TrpRNA结合衰减蛋白TRAP的调节。TRAP介导的色氨酸生物合成基因的调节包括转录衰减和两种不同的翻译控制机制。TRAP还调节trpP（yhaG）的翻译，trpP（yhaG）是编码假定的色氨酸转运蛋白的单基因操纵子。其翻译起始区含有TRAP调控mRNA典型的三联重复序列。我们发现trp和pabA的调节在突变株中没有改变。从过滤结合和凝胶迁移率变化分析的结果表明，TRAP特异性结合到一段的trpPtranscript，其中包括非翻译的领导人和翻译起始区。虽然TRAP对trp和pabA转录物的亲和力相似，但TRAP介导的trp翻译控制比pabA广泛得多。RNA足迹分析显示，trpPTRAP结合位点由9个三联体重复序列（5个GAG，3个UAG和1个AAG）组成，它们围绕并重叠trpPShine-Dalgarno（S-D）序列和翻译起始密码子。从足印和RNA指导的细胞自由翻译实验的结果表明，色氨酸激活的TRAP抑制TrpP的合成，阻止30 S核糖体亚基的结合。综上所述，我们的研究结果表明TRAP通过阻断核糖体结合来调节trpP的翻译。因此，TRAP通过三种不同的机制协调调节色氨酸的合成和转运：减弱trpEDCFBA操纵子的转录，促进trpES-D阻断发夹的形成，以及阻断核糖体与pabA和trpP转录物的结合。
Expression of theBacillus subtilistryptophan biosynthetic genes (trpEDCFBAandpabA[trpG]) is regulated in response to tryptophan by TRAP, thetrpRNA-binding attenuation protein. TRAP-mediated regulation of the tryptophan biosynthetic genes includes a transcription attenuation and two distinct translation control mechanisms. TRAP also regulates translation oftrpP(yhaG), a single-gene operon that encodes a putative tryptophan transporter. Its translation initiation region contains triplet repeats typical of TRAP-regulated mRNAs. We found that regulation oftrpPandpabAis unaltered in arhomutant strain. Results from filter binding and gel mobility shift assays demonstrated that TRAP binds specifically to a segment of thetrpPtranscript that includes the untranslated leader and translation initiation region. While the affinities of TRAP for thetrpPandpabAtranscripts are similar, TRAP-mediated translation control oftrpPis much more extensive than forpabA. RNA footprinting revealed that thetrpPTRAP binding site consists of nine triplet repeats (five GAG, three UAG, and one AAG) that surround and overlap thetrpPShine-Dalgarno (S-D) sequence and translation start codon. Results from toeprint and RNA-directed cell-free translation experiments indicated that tryptophan-activated TRAP inhibits TrpP synthesis by preventing binding of a 30S ribosomal subunit. Taken together, our results establish that TRAP regulates translation oftrpPby blocking ribosome binding. Thus, TRAP coordinately regulates tryptophan synthesis and transport by three distinct mechanisms: attenuation transcription of thetrpEDCFBAoperon, promoting formation of thetrpES-D blocking hairpin, and blocking ribosome binding to thepabAandtrpPtranscripts.