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The Scientific World Journal
Volume 2014, Article ID 921976, 10 pages
Research Article

rre37 Overexpression Alters Gene Expression Related to the Tricarboxylic Acid Cycle and Pyruvate Metabolism in Synechocystis sp. PCC 6803

RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan

Received 4 September 2014; Revised 22 November 2014; Accepted 23 November 2014; Published 28 December 2014

Academic Editor: Anli Geng

Copyright © 2014 Hiroko Iijima et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.