Transcriptional regulation of gene expression inCorynebacterium glutamicum: the role of global, master and local regulators in the modular and hierarchical gene regulatory network

Abstract

The genus Corynebacterium belongs to the taxonomic class Actinobacteria representing the high G+C branch of gram-positive bacteria. Among the most prominent members of this genus is Corynebacterium glutamicum, which is used by the biotechnological industry for the fermentative production of l-amino acids. Because of its industrial importance, C. glutamicum is one of the best-studied gram-positive bacteria and an emerging model for the suborder Corynebacterineae. Over the past years, the transcriptional regulation of gene expression was intensively studied in C. glutamicum to gain insights into the regulatory gene composition and the architecture of the transcriptional regulatory network. Therefore, we have achieved considerable improvements in understanding the regulatory roles of the various transcription regulators and the topology of the gene-regulatory network. This review summarizes the current knowledge of the regulatory gene repertoire and the reconstruction of the transcriptional regulatory network. We describe the functional classification of the detected transcription regulators and their interactions in the gene-regulatory network. Moreover, we provide an overview of the molecular features of transcription regulators and their regulons to integrate these data into the gene-regulatory network and to unravel the flow of information from the environment toward the gene level.

Involvement of Regulatory Interactions among Global Regulators GlxR, SugR, and RamA in Expression of ramA in Corynebacterium glutamicum

“…The current study demonstrated a new regulatory connection between GlxR and RamA, which has a great impact on the C. glutamicum genome-wide transcriptional regulatory network structure (56), because the connection not only expands the GlxR regulon by including the RamA regulon but also newly creates multiple feed-forward loops (FFLs) in the regulatory cascades. The FFL, which is one of the most significant network motifs found in a transcriptional regulatory network in both E. coli (57) and Saccharomyces cerevisiae (58), comprises two cascaded transcription factors that jointly regulate a common gene (59).…”

Maltose Uptake by the Novel ABC Transport System MusEFGK 2 I Causes Increased Expression of ptsG in Corynebacterium glutamicum

“…It seems reasonable to suggest that intermediates of maltose metabolization trigger the positive effect on ptsG expression. In C. glutamicum, transcription of ptsG is controlled by the global regulators RamA, RamB, GlxR, and SugR (27,57,65), which all coordinate the adaptation of the central metabolism of C. glutamicum toward the utilization of carbon sources requiring gluconeogenesis, such as acetate (54). Repression of ptsG in the presence of acetate is mainly caused by SugR (27).…”

AraR, an l -Arabinose-Responsive Transcriptional Regulator in Corynebacterium glutamicum ATCC 31831, Exerts Different Degrees of Repression Depending on the Location of Its Binding Sites within the Three Target Promoter Regions

“…Recent advances in metabolic engineering of C. glutamicum open up new possibilities for efficient utilization of substrates containing mixtures of D-glucose, D-xylose, and L-arabinose (9)(10)(11)(12). Understanding of the unique transcriptional regulatory system of sugar metabolism genes in C. glutamicum (13,14) highlights a potential avenue toward optimization of utilization of sugar mixtures derived from a variety of lignocellulosic feedstocks.…”