Random mutagenesis identifies factors involved in formate-dependent growth of the methanogenic archaeon Methanococcusmaripaludis-猫眼课题宝

随机诱变鉴定了产甲烷古菌 Methanococcusmaripaludis 依赖甲酸盐生长的相关因素

DOI：

发表时间：

2013

期刊：

Zeitschrift für Induktive Abstammungs- und Vererbungslehre

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

C. Sattler;S. Wolf;Julia Fersch;S. Goetz;M. Rother

甲烷是碳循环中的关键中间体，由产甲烷古菌生物产生。大多数产甲烷菌能够通过使用分子氢作为电子供体将CO2还原为甲烷来保存能量（氢营养产甲烷），但是一些氢营养产甲烷菌也可以使用甲酸盐作为电子供体用于产甲烷。甲酸脱氢酶（Fdh）将甲酸氧化为CO2，并参与到产甲烷途径中的还原当量，但与产甲烷菌的甲酸依赖性生理学相关的其他因素的细节不可用。为了更多地了解甲烷球菌菌株JJ的甲酸盐依赖性生长所涉及的因素，我们使用了最近开发的随机体外诱变系统，该系统基于经修饰的昆虫转座因子来创建2，865个染色体转座子突变体，并筛选它们在甲酸盐上的生长受损。一千二百万。maripaludis转座子诱导的突变体表现出这种表型，染色体中的转座子插入位点被定位。在这些基因中，明显影响甲酸盐依赖性生长的是那些编码古细菌转录因子S的基因，一种离子转运调节因子和一氧化碳脱氢酶/乙酰辅酶A合酶。有趣的是，在7个突变体中，转座子定位在10.2 kb的区域，其中编码Fdh 1，生物体中的两种Fdh同种型之一。两个转录起始位点内的10.2 kb的区域可以映射，和转录本的定量显示，转座子插入在该区域减少fdhA 1的表达由于极性效应。

Methane is a key intermediate in the carbon cycle and biologically produced by methanogenic archaea. Most methanogens are able to conserve energy by reducing CO2 to methane using molecular hydrogen as electron donor (hydrogenotrophic methanogenesis), but several hydrogenotrophic methanogens can also use formate as electron donor for methanogenesis. Formate dehydrogenase (Fdh) oxidizes formate to CO2 and is involved in funneling reducing equivalents into the methanogenic pathway, but details on other factors relevant for formate-dependent physiology of methanogens are not available. To learn more about the factors involved in formate-dependent growth of Methanococcus maripaludis strain JJ, we used a recently developed system for random in vitro mutagenesis, which is based on a modified insect transposable element to create 2,865 chromosomal transposon mutants and screened them for impaired growth on formate. Of 12 M. maripaludis transposon-induced mutants exhibiting this phenotype, the transposon insertion sites in the chromosome were mapped. Among the genes, apparently affecting formate-dependent growth were those encoding archaeal transcription factor S, a regulator of ion transport, and carbon monoxide dehydrogenase/acetyl-CoA synthase. Interestingly, in seven of the mutants, transposons were localized in a 10.2 kb region where Fdh1, one of two Fdh isoforms in the organism, is encoded. Two transcription start sites within the 10.2 kb region could be mapped, and quantification of transcripts revealed that transposon insertion in this region diminished fdhA1 expression due to polar effects.