TY  - JOUR
AU  - Wiechert, Johanna
AU  - Filipchyk, Andrei
AU  - Hünnefeld, Max
AU  - Gätgens, Cornelia
AU  - Brehm, Jannis
AU  - Heermann, Ralf
AU  - Frunzke, Julia
TI  - Deciphering the Rules Underlying Xenogeneic Silencing and Counter-Silencing of Lsr2-like Proteins Using CgpS of Corynebacterium glutamicum as a Model
JO  - mBio
VL  - 11
IS  - 1
SN  - 2150-7511
CY  - Washington, DC
PB  - American Society for Microbiology
M1  - FZJ-2020-00097
SP  - e02273-19/mbio/11/1/mBio.02273-19.atom
PY  - 2020
AB  - Lsr2-like nucleoid-associated proteins play an important role as xenogeneic silencers (XS) of horizontally acquired genomic regions in actinobacteria. In this study, we systematically analyzed the in vivo constraints underlying silencing and counter-silencing of the Lsr2-like protein CgpS in Corynebacterium glutamicum. Genome-wide analysis revealed binding of CgpS to regions featuring a distinct drop in GC profile close to the transcription start site (TSS) but also identified an overrepresented motif with multiple A/T steps at the nucleation site of the nucleoprotein complex. Binding of specific transcription factors (TFs) may oppose XS activity, leading to counter-silencing. Following a synthetic counter-silencing approach, target gene activation was realized by inserting operator sites of an effector-responsive TF within various CgpS target promoters, resulting in increased promoter activity upon TF binding. Analysis of reporter constructs revealed maximal counter-silencing when the TF operator site was inserted at the position of maximal CgpS coverage. This principle was implemented in a synthetic toggle switch, which features a robust and reversible response to effector availability, highlighting the potential for biotechnological applications. Together, our results provide comprehensive insights into how Lsr2 silencing and counter-silencing shape evolutionary network expansion in this medically and biotechnologically relevant bacterial phylum.
LB  - PUB:(DE-HGF)16
C6  - pmid:32019787
UR  - <Go to ISI:>//WOS:000518763400112
DO  - DOI:10.1128/mBio.02273-19
UR  - https://juser.fz-juelich.de/record/872604
ER  -