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Applied and Environmental Microbiology, August 2005, p. 4567-4576, Vol. 71, No. 8
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.8.4567-4576.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Analysis of the hupSL Operon of the Nonheterocystous Cyanobacterium Lyngbya majuscula CCAP 1446/4: Regulation of Transcription and Expression under a Light-Dark Regimen

Elsa Leitão,1 Fredrik Oxelfelt,1 Paulo Oliveira,2,{dagger} Pedro Moradas-Ferreira,1,3 and Paula Tamagnini1,2*

Institute for Molecular and Cell Biology (IBMC)—Cellular and Applied Microbiology Unit, University of Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal,1 Department of Botany, Faculty of Sciences, University of Porto, Rua do Campo Alegre 1191, 4150-181 Porto, Portugal,2 Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Largo Abel Salazar 2, 4099-003 Porto, Portugal3

Received 31 January 2005/ Accepted 16 March 2005

This work presents the characterization of an uptake hydrogenase from a marine filamentous nonheterocystous cyanobacterium, Lyngbya majuscula CCAP 1446/4. The structural genes encoding the uptake hydrogenase (hupSL) were isolated and characterized, and regulatory sequences were identified upstream of hupS. In silico analysis highlighted various sets of long repetitive sequences within the hupSL intergenic region and downstream of hupL. The transcriptional regulator that operates global nitrogen control in cyanobacteria (NtcA) was shown to bind to the promoter region, indicating its involvement in the transcriptional regulation of hupSL. Under N2-fixing conditions and a 12-h light/12-h dark regime, H2 uptake activity was shown to follow a daily pattern with a clear maximum towards the end of the dark period, preceded by an increase in the transcript levels initiated in the end of the light phase. Novel antibodies directed against HupL of Lyngbya majuscula CCAP 1446/4 were used to monitor the protein levels throughout the 24-h period. The results suggest that protein turnover occurs, with degradation taking place during the light phase and de novo synthesis occurring during the dark phase, coinciding with the pattern of H2 uptake. Taking into account our results and the established correlation between the uptake hydrogenase activity and N2 fixation in cyanobacteria, it seems probable that both processes are confined to the dark period in aerobically grown cells of Lyngbya majuscula CCAP 1446/4.

* Corresponding author. Mailing address: Institute for Molecular and Cell Biology (IBMC)—Cellular and Applied Microbiology Unit, University of Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal. Phone: 351-226074900. Fax: 351-226099157. E-mail: pmtamagn{at}ibmc.up.pt.

{dagger} Present address: Department of Physiological Botany, Evolutionary Biology Centre, Uppsala University, Villavägen 6, 75236 Uppsala, Sweden.

Applied and Environmental Microbiology, August 2005, p. 4567-4576, Vol. 71, No. 8
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.8.4567-4576.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Weyman, P. D., Pratte, B., Thiel, T. (2008). Transcription of hupSL in Anabaena variabilis ATCC 29413 Is Regulated by NtcA and Not by Hydrogen. Appl. Environ. Microbiol. 74: 2103-2110 [Abstract] [Full Text]  
  • Oliveira, P., Lindblad, P. (2008). An AbrB-Like Protein Regulates the Expression of the Bidirectional Hydrogenase in Synechocystis sp. Strain PCC 6803. J. Bacteriol. 190: 1011-1019 [Abstract] [Full Text]  


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