Positive regulation of sugar catabolic pathways in the cyanobacterium Synechocystis sp PCC 6803 by the group 2 σ factor sigE
Positive regulation of sugar catabolic pathways in the cyanobacterium Synechocystis sp PCC 6803 by the group 2 σ factor sigE
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DOI：
10.1074/jbc.m505043200
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发表时间：
2005-09-02
影响因子：
4.8
通讯作者：
Tanaka, K
中科院分区：
文献类型：
--
作者：
Osanai, T;Kanesaki, Y;Tanaka, K
集胞藻属PCC 6803的sigE基因编码RNA聚合酶的第2组sigma因子，并已被提出在氮代谢的转录调节中起作用。通过使用微阵列和北方分析，我们证明，丰富的转录来自重要的基因糖酵解，氧化戊糖磷酸途径，糖原catalysts减少在sigE突变集胞藻保持在正常的生长条件下。此外，由zwf和gnd基因编码的氧化戊糖磷酸途径的两个关键酶，葡萄糖-6-磷酸脱氢酶和6-磷酸葡萄糖酸脱氢酶的活性也在sigE突变体中降低。突变消除了野生型中明显的酶活性和转录物丰度的暗增强。此外，sigE突变体表现出葡萄糖摄取率降低和细胞内糖原水平增加。此外，它不能在光激活异养生长条件下增殖。这些结果表明SigE在集胞藻PCC 6803中的糖分解代谢途径的转录激活中起作用。
The sigE gene of Synechocystis sp. PCC 6803 encodes a group 2 sigma factor for RNA polymerase and has been proposed to function in transcriptional regulation of nitrogen metabolism. By using microarray and Northern analyses, we demonstrated that the abundance of transcripts derived from genes important for glycolysis, the oxidative pentose phosphate pathway, and glycogen catabolism is reduced in a sigE mutant of Synechocystis maintained under the normal growth condition. Furthermore, the activities of the two key enzymes of the oxidative pentose phosphate pathway, glucose- 6- phosphate dehydrogenase and 6- phophogluconate dehydrogenase, encoded by the zwf and gnd genes were also reduced in the sigE mutant. The dark enhancements in both enzyme activity and transcript abundance apparent in the wild type were eliminated by the mutation. In addition, the sigE mutant showed a reduced rate of glucose uptake and an increased intracellular level of glycogen. Moreover, it was unable to proliferate under the light- activated heterotrophic growth conditions. These results indicate that SigE functions in the transcriptional activation of sugar catabolic pathways in Synechocystis sp. PCC 6803.