| 论文题目: | Mechanism for Stabilizing mRNAs Involved in Methanol-Dependent Methanogenesis of Cold-Adaptive Methanosarcina mazei zm-15 |
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| 作者: | Cao Yi, Li Jie, Jiang Na, Dong Xiuzhu* |
| 联系作者: | Dong Xiuzhu* |
| 刊物名称: | Applied and Environmental Microbiology |
| 期: | 80 |
| 卷: | 4 |
| 页: | 1291-1298 |
| 年份: | 2014 |
| 影响因子: | 4.406 |
| 论文下载: | |
| 摘要: | Methylotrophic methanogenesis predominates at low temperatures in the cold Zoige wetland in Tibet. 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 7.7-fold during growth at 15 degrees C versus 30 degrees C. Methanol-derived methanogenesis decreased only 3-fold under the same conditions, suggesting that it is more cold adaptive. Reverse transcription-quantitative PCR (RT-qPCR) detected <2-fold difference in the transcript abundances of mtaA1, mtaB1, and mtaC1, the methanol methyltransferase (Mta) genes, in 30 degrees C versus 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 ptaackA mRNA half-life was significantly reduced in 15 degrees C culture compared to 30 degrees C culture. Using circularized RNA RT-PCR, large 5' untranslated regions (UTRs) (270 nucleotides [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-adaptive M. mazei zm-15. |
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