Open AccessCellular differentiation and the NtcA transcription factor in filamentous cyanobacteria
Author(s) -
Herrero Antonia,
MuroPastor Alicia M.,
Valladares Ana,
Flores Enrique
Publication year - 2004
Publication title -
fems microbiology reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.91
H-Index - 212
eISSN - 1574-6976
pISSN - 0168-6445
DOI - 10.1016/j.femsre.2004.04.003
Subject(s) - heterocyst , biology , microbiology and biotechnology , cyanobacteria , transcription factor , anabaena , cellular differentiation , gene , regulation of gene expression , genetics , bacteria
Some filamentous cyanobacteria can undergo a variety of cellular differentiation processes that permit their better adaptation to certain environmental conditions. These processes include the differentiation of hormogonia, short filaments aimed at the dispersal of the organism in the environment, of akinetes, cells resistant to various stress conditions, and of heterocysts, cells specialized in the fixation of atmospheric nitrogen in oxic environments. NtcA is a transcriptional regulator that operates global nitrogen control in cyanobacteria by activating (and in some cases repressing) many genes involved in nitrogen assimilation. NtcA is required for the triggering of heterocyst differentiation and for subsequent steps of its development and function. This requirement is based on the role of NtcA as an activator of the expression of hetR and other multiple genes at specific steps of the differentiation process. The products of these genes effect development as well as the distinct metabolism of the mature heterocyst. The different features found in the NtcA‐dependent promoters, together with the cellular level of active NtcA protein, should have a role in the determination of the hierarchy of gene activation during the process of heterocyst differentiation.