Osanai Takashi, Azuma Miyuki, Tanaka Kan
Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Photochem Photobiol Sci. 2007 May;6(5):508-14. doi: 10.1039/b616219n. Epub 2007 Feb 22.
In photosynthetic organisms, sugar catabolic pathways, such as glycolysis and the oxidative pentose phosphate pathway, are indispensable for survival in the absence of light. In this review, we will focus on the regulation of sugar catabolic gene expression in cyanobacteria, especially that of Synechocystis sp. PCC 6803 (Synechocystis). In Synechocystis, the expression of sugar catabolic genes is activated by the shift from light-to-dark and diurnally during the evening, and positively regulated by a histidine kinase, Hik8, and a RNA polymerase sigma factor, SigE. Mutants for these regulators are defective for survival in the dark and unable to carry out light-activated heterotrophic growth. It has also been shown that transcripts of sugar catabolic genes are increased by nitrogen depletion and a global nitrogen regulator NtcA is essential for the induction. These results indicate a regulatory connection between nitrogen status and sugar catabolism in cyanobacteria.
在光合生物中，糖分解代谢途径，如糖酵解和氧化戊糖磷酸途径，对于在无光条件下的生存是不可或缺的。在本综述中，我们将重点关注蓝藻中糖分解代谢基因表达的调控，特别是集胞藻属PCC 6803（集胞藻）。在集胞藻中，糖分解代谢基因的表达在从光照到黑暗的转变过程中以及傍晚时分受到昼夜调节，并由组氨酸激酶Hik8和RNA聚合酶σ因子SigE正向调控。这些调节因子的突变体在黑暗中无法生存，并且无法进行光激活的异养生长。研究还表明，氮素缺乏会增加糖分解代谢基因的转录本，而全局氮调节因子NtcA对于这种诱导至关重要。这些结果表明蓝藻中氮状态与糖分解代谢之间存在调控联系。
