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

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.