Chair of Genetics of Prokaryotes, Bielefeld University, Germany.
J Biotechnol. 2011 Jul 10;154(2-3):149-55. doi: 10.1016/j.jbiotec.2010.07.015. Epub 2010 Jul 16.
The pstSCAB operon of Corynebacterium glutamicum, which encodes a high affinity transport system for uptake of the phosphorus source inorganic phosphate, is induced upon phosphate starvation involving activation by the two-component regulatory system PhoS-PhoR. Partial phosphate starvation induction of the pstSCAB operon in a ΔphoRS mutant indicated the involvement of (an) additional transcriptional regulator(s). Here, GlxR, a global cAMP-dependent transcriptional regulator, was shown to bind to the pstS promoter -133 bp to -117 bp upstream of the transcriptional start site as shown by gel shift and mutation experiments. Transcriptional fusion analysis revealed that GlxR activates the pstSCAB operon under phosphate limiting conditions in a carbon source dependent manner. Commensurate with these findings, overexpression of glxR was shown to stimulate growth under phosphate limiting conditions with glucose, but not with acetate, as carbon source. Thus, in C. glutamicum pstSCAB expression is regulated in response to the availability of phosphorus and carbon sources.
谷氨酸棒杆菌的 pstSCAB 操纵子编码了一种高亲和力的运输系统，用于摄取磷源无机磷酸盐，当涉及到磷酸饥饿时，该操纵子被双组分调节系统 PhoS-PhoR 激活。在 ΔphoRS 突变体中，pstSCAB 操纵子的部分磷酸饥饿诱导表明涉及（一个）额外的转录调节因子。在这里，GlxR，一种全局 cAMP 依赖性转录调节因子，如凝胶迁移和突变实验所示，被证明结合到 pstS 启动子-133bp 到转录起始位点上游的-117bp。转录融合分析显示，GlxR 在磷限制条件下以碳源依赖的方式激活 pstSCAB 操纵子。与这些发现一致，过表达 glxR 被证明可以在以葡萄糖为碳源的磷限制条件下刺激生长，但不以乙酸盐为碳源。因此，在谷氨酸棒杆菌中，pstSCAB 的表达受到磷和碳源可用性的调节。
