Due to the success of the Research Topic
'Bacterial Transcription Factors and the Cell Cycle' and the rapidly evolving subject area, we are pleased to launch volume II of this collection.
Analogous to the eukaryotic G1, S and M phase of the cell cycle, the bacterial cell cycle can be classified into independent stages. Slowly growing bacterial cells undergo three different stages, B-, C- and D-phase, respectively, while the cell cycle of fast-growing bacteria involves at least two independent cycles: the chromosome replication and the cell division.
The oscillation in gene expression regulated by transcription factors, and proteolysis mediated by ClpXP, are closely correlated with progression of the cell cycle. Indeed, it has been shown that DnaA couples DNA replication initiation with the expression of the two oscillating regulators GcrA and CtrA, and the DnaA/GcrA/CtrA regulatory cascade drives the forward progression of the Caulobacter cell cycle. Furthermore, it has been found that: the DnaA oscillation in
Eschericha coli and
Caulobacter crescentus plays an important role in the cell cycle coordination; RpoS in Coxiella regulates the gene expression involved in the developmental cycle; the SigB and SinR transcription factors control whether cells remain in or leave a biofilm responding to metabolic conditions in
Bacillus subtilis; similarly, BolA in most Gram-negative bacteria turns off motility and turns on biofilm development as a transcription factor; CtrA regulates cell division and outer membrane composition of the pathogen
Brucella abortus; an essential transcription factor SciP enhances robustness of Caulobacter cell cycle regulation.
Interestingly, transcription factor mediated metabolism fluctuations are also related to progression of the cell cycle. It has been shown that: CggR and Cra factors are involved in the flux-signaling metabolite fructose-1,6-bisphosphate; IclR mediates para-hydroxybenzoate catabolism in
Streptomyces coelicolor; CceR and AkgR regulate central carbon and energy metabolism in alphaproteobacteria; and these metabolism changes affect cell growth. In line with the argument, AspC-mediated aspartate metabolism coordinates the
E. coli cell cycle.
In Volume I of the Research Topic, (i) transcription factors Mfd, DagR, RsbW homologs, Crp1, and NprR in various bacteria have been characterized; (ii) histone-like nucleoid-binding protein YbaBCc and genome-wide cell cycle-dependent binding patterns of IHF (integration host factor) to chromosomes with base-pair resolution using GeF-seq have been determined; (iii) direct interaction of ZapE with FtsZ and function in cell division are shown. In addition, the dual activity of DnaA in different cellular processes and replication initiation control have been summarized, and the conserved relative location of CtrA phosphorelay associated genes to
ori and
ter of the bacterial circular chromosome are described.
The second volume of this Research Topic is intended to cover the spectrum of cell cycle regulatory mechanisms, in particular the coordination of transcription factor mediated gene transcription oscillations, and the cellular metabolisms associated with the cell cycle. We welcome all types of articles including Original Research, Review, and Mini Review. The subject areas of interest include but are not limited to:
1.) Cell cycle coordination through gene expression and expression oscillation mediated by transcription factors.
2.) Regulation of the cell cycle by proteolysis oscillation.
3.) Coordination of the cell cycle with metabolism fluctuation.
4.) DNA methylation fluctuation and the cell cycle.
5.) Novel transcription factors and gene expression patterns associated with the cell cycle.
