Iijima Hiroko, Watanabe Atsuko, Takanobu Junko, Hirai Masami Yokota, Osanai Takashi
RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
ScientificWorldJournal. 2014;2014:921976. doi: 10.1155/2014/921976. Epub 2014 Dec 28.
The tricarboxylic acid (TCA) cycle and pyruvate metabolism of cyanobacteria are unique and important from the perspectives of biology and biotechnology research. Rre37, a response regulator induced by nitrogen depletion, activates gene expression related to sugar catabolism. Our previous microarray analysis has suggested that Rre37 controls the transcription of genes involved in sugar catabolism, pyruvate metabolism, and the TCA cycle. In this study, quantitative real-time PCR was used to measure the transcript levels of 12 TCA cycle genes and 13 pyruvate metabolism genes. The transcripts of 6 genes (acnB, icd, ppc, pyk1, me, and pta) increased after 4 h of nitrogen depletion in the wild-type GT strain but the induction was abolished by rre37 overexpression. The repression of gene expression of fumC, ddh, and ackA caused by nitrogen depletion was abolished by rre37 overexpression. The expression of me was differently affected by rre37 overexpression, compared to the other 24 genes. These results indicate that Rre37 differently controls the genes of the TCA cycle and pyruvate metabolism, implying the key reaction of the primary in this unicellular cyanobacterium.
从生物学和生物技术研究的角度来看，蓝藻的三羧酸（TCA）循环和丙酮酸代谢具有独特性且十分重要。Rre37是一种由氮耗竭诱导产生的应答调节因子，可激活与糖分解代谢相关的基因表达。我们之前的微阵列分析表明，Rre37控制参与糖分解代谢、丙酮酸代谢和TCA循环的基因转录。在本研究中，采用定量实时PCR来测量12个TCA循环基因和13个丙酮酸代谢基因的转录水平。在野生型GT菌株中，氮耗竭4小时后，6个基因（acnB、icd、ppc、pyk1、me和pta）的转录本增加，但rre37过表达消除了这种诱导作用。rre37过表达消除了由氮耗竭引起的fumC、ddh和ackA基因表达的抑制。与其他24个基因相比，rre37过表达对me的表达有不同的影响。这些结果表明，Rre37对TCA循环和丙酮酸代谢的基因有不同的控制作用，这意味着在这种单细胞蓝藻中初级代谢的关键反应。
