Regulated gene expression in methanogens

: Methanogens form a very large and diverse group of microorganisms within the domain of the Archaea. Energy for their growth is obtained by the reduction of a variety of substrates into methane. Several genes, coding for enzymes involved in methanogenesis or in the central metabolism have been cloned and studied. The molecular features of their expression signals have been compared with bacterial and eukaryal expression signals. This indicated that the transcription process is an intermediate form between the specific processes known in Bacteria and Eukarya. The translation system that is used in Archaea is very similar with the process in Bacteria. Although the molecular features of genes and expression signals in Archaea are well‐studied, investigations on the regulation of gene expression in these organisms are very scarce. In order to give insight into molecular regulatory mechanisms in methanogens, the current knowledge of regulated systems in methanogens will be reviewed in this manuscript.