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 Valladares, A.
Right arrow Articles by Herrero, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Valladares, A.
Right arrow Articles by Herrero, A.

 Previous Article  |  Next Article 

Journal of Bacteriology, September 2008, p. 6126-6133, Vol. 190, No. 18
0021-9193/08/$08.00+0     doi:10.1128/JB.00787-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Transcription Activation by NtcA and 2-Oxoglutarate of Three Genes Involved in Heterocyst Differentiation in the Cyanobacterium Anabaena sp. Strain PCC 7120{triangledown}

Ana Valladares, Enrique Flores, and Antonia Herrero*

Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, E-41092 Seville, Spain

Received 5 June 2008/ Accepted 11 July 2008

In Anabaena sp. strain PCC 7120, differentiation of heterocysts takes place in response to the external cue of combined nitrogen deprivation, allowing the organism to fix atmospheric nitrogen in oxic environments. NtcA, a global transcriptional regulator of cyanobacteria, is required for activation of the expression of multiple genes involved in heterocyst differentiation, including key regulators that are specific to the process. We have set up a fully defined in vitro system, which includes the purified Anabaena RNA polymerase, and have studied the effects of NtcA and its signaling effector 2-oxoglutarate on RNA polymerase binding, open complex formation, and transcript production from promoters of the hetC, nrrA, and devB genes that are activated by NtcA at different stages of heterocyst differentiation. Both RNA polymerase and NtcA could specifically bind to the target DNA in the absence of any effector. 2-Oxoglutarate had a moderate positive effect on NtcA binding, and NtcA had a limited positive effect on RNA polymerase recruitment at the promoters. However, a stringent requirement of both NtcA and 2-oxoglutarate was observed for the detection of open complexes and transcript production at the three investigated promoters. These results support a key role for 2-oxoglutarate in transcription activation in the developing heterocyst.

* Corresponding author. Mailing address: Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Américo Vespucio 49, E-41092 Sevilla, Spain. Phone: 34 954 489522. Fax: 34 954 460065. E-mail: herrero{at}ibvf.csic.es

{triangledown} Published ahead of print on 25 July 2008.

Journal of Bacteriology, September 2008, p. 6126-6133, Vol. 190, No. 18
0021-9193/08/$08.00+0     doi:10.1128/JB.00787-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Paz-Yepes, J., Flores, E., Herrero, A. (2009). Expression and Mutational Analysis of the glnB Genomic Region in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. J. Bacteriol. 191: 2353-2361 [Abstract] [Full Text]  
  • Olmedo-Verd, E., Valladares, A., Flores, E., Herrero, A., Muro-Pastor, A. M. (2008). Role of Two NtcA-Binding Sites in the Complex ntcA Gene Promoter of the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. J. Bacteriol. 190: 7584-7590 [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»