title: A transcriptional regulator Sll0794 regulates tolerance to biofuel ethanol in photosynthetic Synechocystis sp. PCC 6803.
abstract: To improve ethanol production directly from CO2 in photosynthetic cyanobacterial systems, one key issue that needs to be addressed is the low ethanol tolerance of cyanobacterial cells. Our previous proteomic and transcriptomic analyses found that several regulatory proteins were up-regulated by exogenous ethanol in Synechocystis sp. PCC6803. In this study, through tolerance analysis of the gene disruption mutants of the up-regulated regulatory genes, we uncovered that one transcriptional regulator, Sll0794, was related directly to ethanol tolerance in Synechocystis. Using a quantitative iTRAQ-LC-MS/MS proteomics approach coupled with quantitative real-time reverse transcription-PCR (RT-qPCR), we further determined the possible regulatory network of Sll0794. The proteomic analysis showed that in the Δsll0794 mutant grown under ethanol stress a total of 54 and 87 unique proteins were down- and up-regulated, respectively. In addition, electrophoretic mobility shift assays demonstrated that the Sll0794 transcriptional regulator was able to bind directly to the upstream regions of sll1514, slr1512, and slr1838, which encode a 16.6 kDa small heat shock protein, a putative sodium-dependent bicarbonate transporter and a carbon dioxide concentrating mechanism protein CcmK, respectively. The study provided a proteomic description of the putative ethanol-tolerance network regulated by the sll0794 gene, and revealed new insights on the ethanol-tolerance regulatory mechanism in Synechocystis. As the first regulatory protein discovered related to ethanol tolerance, the gene may serve as a valuable target for transcription machinery engineering to further improve ethanol tolerance in Synechocystis. All MS data have been deposited in the ProteomeXchange with identifier PXD001266 (http://proteomecentral.proteomexchange.org/dataset/PXD001266).
authors.affiliation: From the ‡Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China; §Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China; ¶Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China;
authors.forename: Zhongdi
authors.initials: Z
authors.lastname: Song
authors.affiliation: From the ‡Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China; §Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China; ¶Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China; lchen@tju.edu.cn wwzhang8@tju.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: From the ‡Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China; §Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China; ¶Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China;
authors.forename: Jiangxin
authors.initials: J
authors.lastname: Wang
authors.affiliation: ‖Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, P.R. China.
authors.forename: Yinhua
authors.initials: Y
authors.lastname: Lu
authors.affiliation: ‖Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, P.R. China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Jiang
authors.affiliation: From the ‡Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P.R. China; §Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, P.R. China; ¶Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, P.R. China; lchen@tju.edu.cn wwzhang8@tju.edu.cn.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological; D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D056804:Biofuels; D000431:Ethanol / Q000378:metabolism / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000187:drug effects; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020543:Proteome / Q000235:genetics* / Q000378:metabolism; D027982:Sodium-Bicarbonate Symporters / Q000235:genetics / Q000378:metabolism; D046939:Synechocystis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D056804:Biofuels; C103695:CcmK protein, Synechocystis sp.; D006360:Heat-Shock Proteins; D020543:Proteome; D027982:Sodium-Bicarbonate Symporters; D000431:Ethanol