Transcriptional response of Methanosarcina acetivorans to repression of the energy-conserving methanophenazine: CoM-CoB heterodisulfide reductase enzyme HdrED

Methane-producing archaea are key organisms in the anaerobic carbon cycle. These organisms, also called methanogens, grow by converting substrate to methane gas in a process called methanogenesis. Previous research showed that reduction of the terminal electron acceptor is the rate-limiting step in methanogenesis by Methanosarcina acetivorans. In order to gain insight into how the cells sense and respond to availability of the terminal electron acceptor, we designed an experiment to deplete cells of the essential terminal oxidase enzyme, HdrED. We found that depletion of HdrED in vivo results in higher abundance of transcripts for methyltransferases (mtaC2, mtaB3, mtaC3), coenzyme B biosynthesis, C1 metabolism, and pyrimidine compounds. In most cases, these changes were distinct from transcript abundance changes observed during the transition from exponential growth to stationary phase cultures. These data implicate MsrC (MA4383) in CoM-S-S-CoB heterodisulfide sensing and indicate cells have a specific mechanism to sense intracellular ratio of CoM-S-S-CoB, coenzyme M and coenzyme B thiols and further suggest transcripts encoding translation and methanogenesis functions are controlled by feed-forward regulation depending on substrate availability. 16 samples were analyzed: +Tet exponential (two technical replicates), +Tet stationary (two technical replicates, -Tet 24h (three biological replicates, -Tet 30h (two biological replicates, -Tet 36h (two biological replicates, -Tet 42h (three biological replicates), -Tet 48h (two biological replicates. *** Submitter states that only RMA files and the scans of the slides are available for the GEO submission ***