351. Characterization of an Archaeal Two-Component System That Regulates Methanogenesis in Methanosaeta harundinacea
- Author
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Xiuzhu Dong, Xiaopeng Guo, Lei Qi, Xin Zheng, and Jie Li
- Subjects
Chromatin Immunoprecipitation ,Transcription, Genetic ,Operon ,Molecular Sequence Data ,Protein domain ,lcsh:Medicine ,Biology ,Microbiology ,Genes, Archaeal ,Genes, Reporter ,Bacterial transcription ,Gene Order ,Molecular Cell Biology ,Electrophoretic mobility shift assay ,Amino Acid Sequence ,Phosphorylation ,Archaean Biology ,lcsh:Science ,Promoter Regions, Genetic ,Genetics ,Evolutionary Biology ,Multidisciplinary ,Archaeal Biochemistry ,Gene Expression Profiling ,Methanol ,Archaeal Evolution ,lcsh:R ,Mechanisms of Signal Transduction ,Histidine kinase ,Biology and Life Sciences ,Methanosarcinaceae ,Promoter ,Cell Biology ,Archaeal Physiology ,Organismal Evolution ,Two-component regulatory system ,Response regulator ,Biochemistry ,Microbial Evolution ,lcsh:Q ,Sequence Alignment ,Signal Transduction ,Research Article - Abstract
Two-component signal transduction systems (TCSs) are a major mechanism used by bacteria in response to environmental changes. Although many sequenced archaeal genomes encode TCSs, they remain poorly understood. Previously, we reported that a methanogenic archaeon, Methanosaeta harundinacea, encodes FilI, which synthesizes carboxyl-acyl homoserine lactones, to regulate transitions of cellular morphology and carbon metabolic fluxes. Here, we report that filI, the cotranscribed filR2, and the adjacent filR1 constitute an archaeal TCS. FilI possesses a cytoplasmic kinase domain (histidine kinase A and histidine kinase-like ATPase) and its cognate response regulator. FilR1 carries a receiver (REC) domain coupled with an ArsR-related domain with potential DNA-binding ability, while FilR2 carries only a REC domain. In a phosphorelay assay, FilI was autophosphorylated and specifically transferred the phosphoryl group to FilR1 and FilR2, confirming that the three formed a cognate TCS. Through chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-qPCR) using an anti-FilR1 antibody, FilR1 was shown to form in vivo associations with its own promoter and the promoter of the filI-filR2 operon, demonstrating a regulatory pattern common among TCSs. ChIP-qPCR also detected FilR1 associations with key genes involved in acetoclastic methanogenesis, acs4 and acs1. Electrophoretic mobility shift assays confirmed the in vitro tight binding of FilR1 to its own promoter and those of filI-filR2, acs4, and mtrABC. This also proves the DNA-binding ability of the ArsR-related domain, which is found primarily in Archaea. The archaeal promoters of acs4, filI, acs1, and mtrABC also initiated FilR1-modulated expression in an Escherichia coli lux reporter system, suggesting that FilR1 can up-regulate both archaeal and bacterial transcription. In conclusion, this work identifies an archaeal FilI/FilRs TCS that regulates the methanogenesis of M. harundinacea.
- Published
- 2014