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Effects of PipX on NtcA‐dependent promoters and characterization of the cox3 promoter region in the heterocyst‐forming cyanobacterium Anabaena sp. PCC 7120
Author(s) -
Camargo Sergio,
Valladares Ana,
Forchhammer Karl,
Herrero Antonia
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.03.039
Subject(s) - heterocyst , promoter , operon , anabaena , biology , transcription factor , gene , microbiology and biotechnology , nostoc , gene expression , dna , cyanobacteria , genetics , bacteria , mutant
In Anabaena , the pipX gene is induced in the cells differentiating into heterocysts, being the PipX factor required for full expression of late heterocyst‐specific genes. Here we show that PipX has a positive effect on in vitro binding of the transcription factor NtcA to DNA, as well as on transcript production, in different NtcA‐dependent promoters. We found that the cox3 operon, encoding a heterocyst‐specific terminal respiratory oxidase, is expressed from three nitrogen‐regulated promoters to which NtcA binds. At the three sites, NtcA binding is potentiated by PipX. Thus, PipX has a direct effect on gene expression influencing the activity of NtcA.