title: Silencing of cryptic prophages in Corynebacterium glutamicum.
abstract: DNA of viral origin represents a ubiquitous element of bacterial genomes. Its integration into host regulatory circuits is a pivotal driver of microbial evolution but requires the stringent regulation of phage gene activity. In this study, we describe the nucleoid-associated protein CgpS, which represents an essential protein functioning as a xenogeneic silencer in the Gram-positive Corynebacterium glutamicum CgpS is encoded by the cryptic prophage CGP3 of the C. glutamicum strain ATCC 13032 and was first identified by DNA affinity chromatography using an early phage promoter of CGP3. Genome-wide profiling of CgpS binding using chromatin affinity purification and sequencing (ChAP-Seq) revealed its association with AT-rich DNA elements, including the entire CGP3 prophage region (187 kbp), as well as several other elements acquired by horizontal gene transfer. Countersilencing of CgpS resulted in a significantly increased induction frequency of the CGP3 prophage. In contrast, a strain lacking the CGP3 prophage was not affected and displayed stable growth. In a bioinformatics approach, cgpS orthologs were identified primarily in actinobacterial genomes as well as several phage and prophage genomes. Sequence analysis of 618 orthologous proteins revealed a strong conservation of the secondary structure, supporting an ancient function of these xenogeneic silencers in phage-host interaction.
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Eugen
authors: E
authors: Pfeifer
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Max
authors: M
authors: Hünnefeld
authors: Quantitative and Theoretical Biology, Heinrich-Heine-Universität Düsseldorf, 40225, Düsseldorf, Germany.
authors: Ovidiu
authors: O
authors: Popa
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Tino
authors: T
authors: Polen
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Dietrich
authors: D
authors: Kohlheyer
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Meike
authors: M
authors: Baumgart
authors: Institute of Bio- und Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany j.frunzke@fz-juelich.de.
authors: Julia
authors: J
authors: Frunzke
mesh_terms: D020856:AT Rich Sequence; D039903:Actinobacteria / Q000235:genetics; D048230:Corynebacterium glutamicum / Q000235:genetics*; D004279:DNA, Viral / Q000378:metabolism; D020868:Gene Silencing; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D055106:Genome-Wide Association Study; D039002:Prophages / Q000235:genetics* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins