Skip Navigation

This Article
Right arrow Print PDF (705K)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
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 Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (36)
Right arrowRequest Permissions
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Nees, D. W.
Right arrow Articles by Ludwig, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nees, D. W.
Right arrow Articles by Ludwig, R. A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nucleic Acids Research, 1988, Vol. 16, No. 20 9839-9853
© 1988

Articles

The Azorhizobium caulinodans nifA gene: identification of upstream-activating sequences including a new element, the ‘anaerobox’

David W. Nees, Pascal A. Stein and Robert A. Ludwig

Department of Biology, Thimann Laboratories, University of California Santa Cruz, CA 95064, USA

Received June 8, 1988. Accepted September 12, 1988.

From nucleotide sequencing analyses, the A. caulinodans nifA gene seems to be under dual control by the Ntr (in response to available N) and Fnr (in response to available O2) transcriptional activation/ repression systems. Because it fixes N2 in two contexts, the Ntr system might regulate A. caulinodans nif gene expression ex planta, while the Fnr system might similarly regulate in planta. As nifA upstream-activating elements, we have identified: (i) a gpNifA binding site allowing autogenous nifA regulation, (ii) an Ntr-dependent transcription start, presumably the target of gpNifA activation, and (iii) an "anaerobox" tetradecameric nucleotide sequence that is precisely conserved among O2 regulated enteric bacterial genes controlled by the gpFnr transcriptional activator. Because it is precisely positioned upstream of enteric bacterial transcriptional starts, the "amaerobox" sequence may constitute the gpFnr DNA binding site. If so, then a second, Ntr-independent nifA transcription start may exist. We have also deduced the A. caulinodans nifA open reading frame and have compared the gene product (gpNifA) with those of other N2-fixing organisms. These proteins exhibit strongly conserved motifs: (i) sites conserved among ATP-binding proteins, (ii) an interdomain linker region, and (iii) a Cterminal {alpha}-helix-turn-{alpha}helix DNA binding site.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Appl. Environ. Microbiol.Home page
S. Suzuki, T. Aono, K.-B. Lee, T. Suzuki, C.-T. Liu, H. Miwa, S. Wakao, T. Iki, and H. Oyaizu
Rhizobial Factors Required for Stem Nodule Maturation and Maintenance in Sesbania rostrata-Azorhizobium caulinodans ORS571 Symbiosis
Appl. Envir. Microbiol., October 15, 2007; 73(20): 6650 - 6659.
[Abstract] [Full Text] [PDF]

Home page
 MicrobiologyHome page
E. M. Souza, F. O. Pedrosa, L. U. Rigo, H. B. Machado, and M. G. Yates
Expression of the nifA gene of Herbaspirillum seropedicae: role of the NtrC and NifA binding sites and of the -24/-12 promoter element
Microbiology, June 1, 2000; 146(6): 1407 - 1418.
[Abstract] [Full Text]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.