Transcription and regulation of the hydrogenase(s) accessory genes, hypFCDEAB , in the cyanobacterium Lyngbya majuscula
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ORIGINAL PAPER
Transcription and regulation of the hydrogenase(s) accessory genes, hypFCDEAB, in the cyanobacterium Lyngbya majuscula CCAP 1446/4 Daniela Ferreira · Elsa Leitão · Johannes Sjöholm · Paulo Oliveira · Peter Lindblad · Pedro Moradas-Ferreira · Paula Tamagnini
Received: 5 February 2007 / Revised: 18 May 2007 / Accepted: 22 June 2007 / Published online: 17 July 2007 © Springer-Verlag 2007
Abstract Lyngbya majuscula CCAP 1446/4 is a Wlamentous cyanobacterium possessing both an uptake and a bidirectional hydrogenase. The presence of a single copy of the hyp operon in the cyanobacterial genomes suggests that these accessory genes might be responsible for the maturation of both hydrogenases. We investigated the concomitant transcription of hypFCDEAB with the hydrogenases structural genes—hup and hox. RT-PCRs performed with L. majuscula cells grown under diVerent physiological conditions showed a substantial decrease in the relative amount of hupL transcript under non-N2-Wxing conditions. In contrast, no signiWcant diVerences were observed for the transcript levels of hypFCDEAB in all conditions tested, while minor Xuctuations could be discerned for hoxH. Previously, it was demonstrated that the transcriptional regulators NtcA
and LexA interact with the promoter regions of hup and hox, respectively, and that putative binding sites for both proteins are present in the hyp promoter of L. majuscula. Therefore, a putative involvement of NtcA and LexA in the regulation of the hyp transcription was investigated. Electrophoretic mobility shift assays resulted in NtcA or LexAbound retarded fragments, suggesting the involvement of these proteins in the transcriptional regulation of hypFCDEAB. Keywords Lyngbya majuscula · hyp · Hydrogenase accessory genes · Transcriptional regulator factors · NtcA · LexA
Introduction Communicated by Mary Allen. D. Ferreira · E. Leitão · P. Moradas-Ferreira · P. Tamagnini (&) IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal e-mail: [email protected] D. Ferreira · P. Tamagnini Departamento de Botânica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 1191, 4150-181 Porto, Portugal P. Moradas-Ferreira Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Largo Abel Salazar 2, 4099-003 Porto, Portugal J. Sjöholm · P. Oliveira · P. Lindblad Department of Photochemistry and Molecular Science, The Ångström Laboratories, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
Lyngbya majuscula is a marine Wlamentous non-heterocystous cyanobacterium capable of forming benthic mats that eventually may rise to the water’s surface through the accumulation of gas bubbles and Xoat freely (Watkinson et al. 2005). This cyanobacterium has the ability to form toxic blooms with signiWcant eVects on both ecosystems and human health and is most probably one of the key players in the marine N2 Wxation of tropical and subtropical regions (Osborne et al. 2001; Omoregie et al. 2004). Lyngbya ma
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