This Article Full Text Full Text (PDF) Supplemental material Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Guss, A. M. Articles by Metcalf, W. W. Search for Related Content PubMed PubMed Citation Articles by Guss, A. M. Articles by Metcalf, W. W.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 2009, p. 2826-2833, Vol. 191, No. 8
0021-9193/09/$08.00+0     doi:10.1128/JB.00563-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Differences in Hydrogenase Gene Expression between Methanosarcina acetivorans and Methanosarcina barkeri ^,

Adam M. Guss, Gargi Kulkarni, and William W. Metcalf^*

Department of Microbiology, University of Illinois at Urbana-Champaign, B103 CLSL, 601 South Goodwin, Urbana, Illinois 61801

Received 23 April 2008/ Accepted 28 January 2009

Methanosarcina acetivorans C2A encodes three putative hydrogenases, including one cofactor F₄₂₀-linked (frh) and two methanophenazine-linked (vht) enzymes. Comparison of the amino acid sequences of these putative hydrogenases to those of Methanosarcina barkeri and Methanosarcina mazei shows that each predicted subunit contains all the known residues essential for hydrogenase function. The DNA sequences upstream of the genes in M. acetivorans were aligned with those in other Methanosarcina species to identify conserved transcription and translation signals. The M. acetivorans vht promoter region is well conserved among the sequenced Methanosarcina species, while the second vht-type homolog (here called vhx) and frh promoters have only limited similarity. To experimentally determine whether these promoters are functional in vivo, we constructed and characterized both M. acetivorans and M. barkeri strains carrying reporter gene fusions to each of the M. acetivorans and M. barkeri hydrogenase promoters. Generally, the M. acetivorans gene fusions are not expressed in either organism, suggesting that cis-acting mutations inactivated the M. acetivorans promoters. The M. barkeri hydrogenase gene fusions, on the other hand, are expressed in both organisms, indicating that M. acetivorans possesses the machinery to express hydrogenases, although it does not express its own hydrogenases. These data are consistent with specific inactivation of the M. acetivorans hydrogenase promoters and highlight the importance of testing hypotheses generated by using genomic data.

---

* Corresponding author. Mailing address: Department of Microbiology, University of Illinois at Urbana-Champaign, 601 South Goodwin Avenue, Urbana, IL 61801. Phone: (217) 244-1943. Fax: (217) 244-6697. E-mail: metcalf{at}uiuc.edu

Published ahead of print on 6 February 2009.

Supplemental material for this article may be found at http://jb.asm.org/.

Present address: Departments of Organismic and Evolutionary Biology and of Microbiology and Molecular Genetics, Harvard University, 16 Divinity Ave., Biolabs 4081, Cambridge, MA 02143.

---

Journal of Bacteriology, April 2009, p. 2826-2833, Vol. 191, No. 8
0021-9193/09/$08.00+0     doi:10.1128/JB.00563-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Kulkarni, G., Kridelbaugh, D. M., Guss, A. M., Metcalf, W. W. (2009). Hydrogen is a preferred intermediate in the energy-conserving electron transport chain of Methanosarcina barkeri. Proc. Natl. Acad. Sci. USA 106: 15915-15920 [Abstract] [Full Text]