This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Skibinski, D. A. G.
Right arrow Articles by Andrews, S. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Skibinski, D. A. G.
Right arrow Articles by Andrews, S. C.

 Previous Article  |  Next Article 

Journal of Bacteriology, December 2002, p. 6642-6653, Vol. 184, No. 23
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.23.6642-6653.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Regulation of the Hydrogenase-4 Operon of Escherichia coli by the {sigma}54-Dependent Transcriptional Activators FhlA and HyfR

David A. G. Skibinski,1,2 Paul Golby,1,{dagger} Yung-Sheng Chang,1 Frank Sargent,3 Ralf Hoffman,1 R. Harper,1 John R. Guest,2 Margaret M. Attwood,2 Ben C. Berks,4 and Simon C. Andrews1*

School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ,1 Department of Molecular Biology & Biotechnology, University of Sheffield, Sheffield S10 2TN,2 The Centre of Metalloprotein Spectroscopy & Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ,3 Department of Biochemistry, University of Oxford, Oxford, United Kingdom4

Received 6 May 2002/ Accepted 30 August 2002

The hyf locus (hyfABCDEFGHIJ-hyfR-focB) of Escherichia coli encodes a putative 10-subunit hydrogenase complex (hydrogenase-4 [Hyf]); a potential {sigma}54-dependent transcriptional activator, HyfR (related to FhlA); and a putative formate transporter, FocB (related to FocA). In order to gain insight into the physiological role of the Hyf system, we investigated hyf expression by using a hyfA-lacZ transcriptional fusion. This work revealed that hyf is induced under fermentative conditions by formate at a low pH and in an FhlA-dependent fashion. Expression was {sigma}54 dependent and was inhibited by HycA, the negative transcriptional regulator of the formate regulon. Thus, hyf expression resembles that of the hyc operon. Primer extension analysis identified a transcriptional start site 30 bp upstream of the hyfA structural gene, with appropriately located -24 and -12 boxes indicative of a {sigma}54-dependent promoter. No reverse transcriptase PCR product could be detected for hyfJ-hyfR, suggesting that hyfR-focB may be independently transcribed from the rest of the hyf operon. Expression of hyf was strongly induced (~1,000-fold) in the presence of a multicopy plasmid expressing hyfR from a heterologous promoter. This induction was dependent on low pH, anaerobiosis, and postexponential growth and was weakly enhanced by formate. The hyfR-expressing plasmid increased fdhF-lacZ transcription just twofold but did not influence the expression of hycB-lacZ. Interestingly, inactivation of the chromosomal hyfR gene had no effect on hyfA-lacZ expression. Purified HyfR was found to specifically interact with the hyf promoter/operator region. Inactivation of the hyf operon had no discernible effect on growth under the range of conditions tested. No Hyf-derived hydrogenase or formate dehydrogenase activity could be detected, and no Ni-containing protein corresponding to HyfG was observed.

* Corresponding author. Mailing address: School of Animal and Microbial Sciences, The University of Reading, Reading RG6 6AJ, United Kingdom. Phone: 118 931 8463. Fax: 118 931 0180. E-mail: s.c.andrews{at}reading.ac.uk.

{dagger} Present address: The VLA Weybridge, Weybridge, Surrey KT15 3NB, United Kingdom.

Journal of Bacteriology, December 2002, p. 6642-6653, Vol. 184, No. 23
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.23.6642-6653.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Pandey, J., Koyuturk, M., Kim, Y., Szpankowski, W., Subramaniam, S., Grama, A. (2007). Functional annotation of regulatory pathways. Bioinformatics 23: i377-i386 [Abstract] [Full Text]  
  • Coppi, M. V. (2005). The hydrogenases of Geobacter sulfurreducens: a comparative genomic perspective. Microbiology 151: 1239-1254 [Abstract] [Full Text]  
  • Fukiya, S., Mizoguchi, H., Tobe, T., Mori, H. (2004). Extensive Genomic Diversity in Pathogenic Escherichia coli and Shigella Strains Revealed by Comparative Genomic Hybridization Microarray. J. Bacteriol. 186: 3911-3921 [Abstract] [Full Text]  
  • Blokesch, M., Rohrmoser, M., Rode, S., Bock, A. (2004). HybF, a Zinc-Containing Protein Involved in NiFe Hydrogenase Maturation. J. Bacteriol. 186: 2603-2611 [Abstract] [Full Text]  
  • Self, W. T., Hasona, A., Shanmugam, K. T. (2004). Expression and Regulation of a Silent Operon, hyf, Coding for Hydrogenase 4 Isoenzyme in Escherichia coli. J. Bacteriol. 186: 580-587 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»