We work with the genus Methanococcus , a member of the methanogenic Archaea. The methanogens evidently originated early in the evolution of life and today occupy anaerobic habitats ranging from hydrothermal vents to animal digestive tracts. Much of the lab concentrates on nitrogen regulation as a model for regulation in the Archaea. The repression mechanism is currently an area of intense study in the lab, since little is known about repression in the Archaea. Another aspect of nitrogen regulation occurs at a post-transcriptional level.
Nitrogenase catalyzes nitrogen fixation, an important yet energetically expensive process.
We are studying the nature of the switch-off mechanism and how it differs from analogous mechanisms in Bacteria. Recently we discovered that the mechanism involves divergent members of a nitrogen regulator protein family that is widespread in Bacteria and Archaea. We are expanding our studies of regulation to the genomic level. We are collaborating with the University of Washington Genome Center to determine the genome sequence of M. maripaludis , and with the Center for Expression Array Analysis to study global regulation. In addition, Leigh is a participating faculty member in the Astrobiology Program at the University of Washington.