ISSN:
1617-4623
Keywords:
Azorhizobium caulinodans
;
Nitrogen fixation
;
fixABCX genes
;
Gene regulation
;
mRNA processing
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary We report here the transcriptional analysis of the fixABCXORF1 region of Azorhizobium caulinodans. This led to the identification of a 0.9 kb transcript covering fixX and ORF1, which was synthesized only under conditions of nitrogen fixation. The 5′ end of this transcript was mapped by primer extension and S 1 nuclease protection analyses and shown to be located 70 ± 1 nucleotides upstream of the fixX start codon. By means of transcriptional fixX- and ORF1-lacZ fusions, it was shown that fixX and ORF1 were most probably transcribed from the fixA promoter and that expression of fixX and ORF1 was dependent on NifA activation. This suggests that the 0.9 kb mRNA results from post-transcriptional processing of a large mRNA covering fix-A,B,C,X and ORF1. In addition, ORF1 mutants were constructed and were shown not to be impaired in nitrogenase activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00279389
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