Re1A protein is involved in induction of genetic competence in certain Bacillus subtilis strains by moderating the level of intracellular GTP
Re1A protein is involved in induction of genetic competence in certain Bacillus subtilis strains by moderating the level of intracellular GTP
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DOI：
10.1128/jb.184.14.3923-3930.2002
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发表时间：
2002-07-01
影响因子：
3.2
通讯作者：
Ochi, K
中科院分区：
文献类型：
--
作者：
Inaoka, T;Ochi, K
我们发现某松弛型（reLA）天冬氨酸营养不良菌株的遗传能力明显低于等基因严格型（reLA(+)）菌株。利用lacZ报告基因的转录融合分析表明，与严格菌株相比，宽松菌株中ComK蛋白的数量大大减少，而ComK蛋白是能力发展的关键蛋白。我们还发现，添加了一种GMP合成酶抑制剂decoyinine，在松弛菌株中诱导了一个能力基因（comG）的表达，并伴随着高效液相色谱法测量的细胞内GTP水平的显著下降。在0（指数生长阶段向平稳生长阶段的过渡点）加入癸氨酸后，松弛应变的转化效率提高了100倍。相反，添加鸟苷和癸氨酸完全抵消了添加癸氨酸对能力发展的影响。此外，通过破坏codY基因，松弛菌株的能力发展受损能力完全恢复，codY基因是已知的负性控制comK表达的基因。我们的研究结果表明，至少在某些生理条件下，RelA蛋白通过降低细胞内GTP水平和克服cody介导的调节，在诱导能力发展中起着重要作用。
We found that the ability to develop genetic competence of a certain relaxed (reLA) aspartate-auxotrophic strain of Bacillus subtilis is significantly lower than that of the isogenic stringent (relA(+)) strain. Transcriptional fusion analysis utilizing a lacZ reporter gene indicated that the amount of the ComK protein, known as the key protein for competence development, is greatly reduced in the relaxed strain than in the stringent strain. We also found that the addition of decoyinine, a GMP synthetase inhibitor, induces expression of a competence gene (comG) in the relaxed strain, accompanied by a pronounced decrease in the level of intracellular GTP as measured by high-performance liquid chromatography. The transformation efficiency of the relaxed strain increased 100-fold when decoyinine was added at t0 (the transition point between exponential to stationary growth phase). Conversely, supplementation of guanosine together with decoyinine completely abolished the observed effect of adding decoyinine on competence development. Furthermore, the impaired ability of the relaxed strain for competence development was completely restored by disrupting the codY gene, which is known to negatively control comK expression. Our results indicate that the RelA protein plays an essential role in the induction of competence development at least under certain physiological conditions by reducing the level of intracellular GTP and overcoming CodY-mediated regulation.