嗜热凝结芽孢杆菌DNA甲基化模式的温度响应机制

Methylation is the most common epigenetic modification in bacteria, which is involved in replication, virulence, antibiotic resistance, and other important physiological activities. With excellent thermos-tolerance (open condition fermentation), high carbon metabolic rate, barren resistance, good robustness, Bacillus coagulans strains are considered as important industrial strains, which have potential for developing chasses of synthetic biology. Previous research SMRT sequencing shows that DNA methylation patterns of Bacillus coagulans strains change with the temperature change. This suggests an important metabolic function of DNA methylation in temperature adaptation. In this proposal, epigenetics of two genome-sequencing Bacillus coagulans strains will be systematically investigated including DNA methylation pattern, methylation mechanism, and methylation related physiological function. The expectation is to reveal the epigenetic DNA modification mechanism, and to clarify the role of methylation in strain temperature adaptation. A comprehensive analysis will be firstly conducted based on the previous results obtained in SMRT and RNA-Seq, to look for key genes involved in methylation pattern formation. Then the genes will be cloned, expressed and characterized. Simultaneously, the comprehensive analysis will be used to look for target genes which are regulated by methylation. The target genes will be overexpressed and knocked out for investigating the relationship between the methylation and heat resistance. It is expected that methylation mechanism of Bacillus coagulans will be elucidated and new mechanism of heat tolerance might be discovered in this research.

甲基化是细菌中普遍存在的表观修饰，参与DNA复制、细菌毒力、抗生素抗性等重要生命活动。嗜热凝结芽孢杆菌，是一种重要的工业菌株，热耐受性好（可开放发酵）、耐贫瘠、鲁棒性好，具有发展成为平台菌株的巨大潜力和优势。课题组在前期的单分子实时测序（SMRT）研究中发现其DNA甲基化的程度和模式会随着温度变化而改变，暗示了DNA甲基化和嗜热之间存在关联，这一现象在以往的研究中尚未见报道。本课题以此为契机，拟系统地研究凝结芽孢杆菌的DNA甲基化形成机制与生理功能，以阐明甲基化在细菌耐热中的作用。本课题将综合分析已经获得的SMRT测序和RNA-Seq结果，对甲基化响应关键基因进行克隆和鉴定。同时，鉴定受甲基化调控的靶基因，并研究其和温度适应的关系。预期本研究可阐明凝结芽孢杆菌中甲基化的形成机制，揭示DNA表观修饰和细菌耐热之间的联系，并有望发现新的细菌嗜热机制。

甲基化是细菌中普遍存在的表观修饰，参与DNA复制、细菌毒力、抗生素抗性等重要生命活动。嗜热凝结芽孢杆菌，是一种重要的工业菌株，热耐受性好（可开放发酵）、耐贫瘠、鲁棒性好，具有发展成为平台菌株的巨大潜力和优势。课题组在前期的单分子实时测序（SMRT）研究中发现其DNA甲基化的程度和模式会随着温度变化而改变，暗示了DNA甲基化和嗜热之间存在关联，这一现象在以往的研究中尚未见报道。本课题以此为契机，系统地研究了凝结芽孢杆菌的DNA甲基化形成机制与生理功能，阐明了甲基化在细菌耐热中的作用。本课题综合分析了已经获得的SMRT测序和RNA-Seq结果，对甲基化响应关键基因进行了克隆和鉴定。同时，鉴定了受甲基化调控的靶基因，并研究其和温度适应的关系。本研究阐明了凝结芽孢杆菌中甲基化的形成机制，揭示了DNA表观修饰和细菌耐热之间的联系，发现了新的细菌嗜热机制。