Mechanism for stabilizing mRNAs involved in methanol-dependent methanogenesis of cold adaptive Methanosarcina mazei zm-15----中国科学院微生物研究所

科研成果

论文题目:	Mechanism for stabilizing mRNAs involved in methanol-dependent methanogenesis of cold adaptive Methanosarcina mazei zm-15
作者:	Cao Yi, Li Jie, Jiang Na, Dong Xiuzhu*
联系作者:	Dong Xiuzhu*
刊物名称:	Applied and Environmental Microbiology
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年份:	2013
影响因子:	4.406
论文下载:	http://aem.asm.org/content/early/2013/12/03/AEM.03495-13.long
摘要:	Methylotrophic methanogenesis predominates at low temperatures in the cold Zoige wetland. To elucidate the basis of cold-adapted methanogenesis in these habitats, Methanosarcina mazei zm-15 was isolated and the molecular basis of its cold activity was studied. For this strain, aceticlastic methanogenesis was reduced for 7.7-fold during growth at 15 degrees C versus 30 degrees C. Methanol-derived methanogenesis only decreased 3-fold under the same conditions, suggesting that the latter is more cold adaptive. RT-qPCR determined < 2-fold difference of the transcript abundance of mtaA1, mtaB1 and mtaC1, the methanol methyltransferase (Mta) genes, in 30 degrees C- vs. 15 degrees C-culture, while ackA and pta mRNAs, encoding acetate kinase (Ack) and phosphotransacetylase (Pta) in aceticlastic methanogenesis, were 4.5- and 6.8-fold higher in 30 degrees C-culture than in 15 degrees C-culture. The in vivo half-lives of mtaA1 and mtaC1B1 mRNAs were similar in 30 degrees C- and 15 degrees C-cultures. However, the pta-ackA mRNA half-life was significantly reduced in 15 degrees C-culture than in 30 degrees C-culture. Using circularized RNA RT-PCR, large 5'UTRs (270 nt and 238 nt) were identified for mtaA1 and mtaC1B1 mRNAs, while only a 27-nt 5'UTR was present in the pta-ackA transcript. Removal of the 5'UTRs significantly reduced the in vitro half-lives of mtaA1 and mtaC1B1 mRNAs. Remarkably, fusion of the mtaA1 or mtaC1B1 5'UTRs to pta-ackA mRNA increased its in vitro half-life at both 30 degrees C and 15 degrees C. These results demonstrate that the large 5'UTRs significantly enhance the stability of the mRNAs involved in methanol-derived methanogenesis in the cold adapted M. mazei zm-15.