TY  - JOUR
A1  - Heidrich, Nadja
A1  - Bauriedl, Saskia
A1  - Barquist, Lars
A1  - Li, Lei
A1  - Schoen, Christoph
A1  - Vogel, Jörg
T1  - The primary transcriptome of Neisseria meningitidis and its interaction with the RNA chaperone Hfq
JF  - Nucleic Acids Research
N2  - Neisseria meningitidis is a human commensal that can also cause life-threatening meningitis and septicemia. Despite growing evidence for RNA-based regulation in meningococci, their transcriptome structure and output of regulatory small RNAs (sRNAs) are incompletely understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptome of N. meningitidis strain 8013. Annotation of 1625 transcriptional start sites defines transcription units for most protein-coding genes but also reveals a paucity of classical σ70-type promoters, suggesting the existence of activators that compensate for the lack of −35 consensus sequences in N. meningitidis. The transcriptome maps also reveal 65 candidate sRNAs, a third of which were validated by northern blot analysis. Immunoprecipitation with the RNA chaperone Hfq drafts an unexpectedly large post-transcriptional regulatory network in this organism, comprising 23 sRNAs and hundreds of potential mRNA targets. Based on this data, using a newly developed gfp reporter system we validate an Hfq-dependent mRNA repression of the putative colonization factor PrpB by the two trans-acting sRNAs RcoF1/2. Our genome-wide RNA compendium will allow for a better understanding of meningococcal transcriptome organization and riboregulation with implications for colonization of the human nasopharynx.
KW  - RNA
KW  - Neisseria meningitidis
KW  - dRNA-seq
KW  - transcriptome
KW  - RNA chaperone Hfq
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170828
VL  - 45
IS  - 10
ER  - 
TY  - JOUR
A1  - Klughammer, Johanna
A1  - Dittrich, Marcus
A1  - Blom, Jochen
A1  - Mitesser, Vera
A1  - Vogel, Ulrich
A1  - Frosch, Matthias
A1  - Goesmann, Alexander
A1  - Müller, Tobias
A1  - Schoen, Christoph
T1  - Comparative genome sequencing reveals within-host genetic changes in Neisseria meningitidis during invasive disease
JF  - PLoS ONE
N2  - Some members of the physiological human microbiome occasionally cause life-threatening disease even in immunocompetent individuals. A prime example of such a commensal pathogen is Neisseria meningitidis, which normally resides in the human nasopharynx but is also a leading cause of sepsis and epidemic meningitis. Using N. meningitidis as model organism, we tested the hypothesis that virulence of commensal pathogens is a consequence of within host evolution and selection of invasive variants due to mutations at contingency genes, a mechanism called phase variation. In line with the hypothesis that phase variation evolved as an adaptation to colonize diverse hosts, computational comparisons of all 27 to date completely sequenced and annotated meningococcal genomes retrieved from public databases showed that contingency genes are indeed enriched for genes involved in host interactions. To assess within-host genetic changes in meningococci, we further used ultra-deep whole-genome sequencing of throat-blood strain pairs isolated from four patients suffering from invasive meningococcal disease. We detected up to three mutations per strain pair, affecting predominantly contingency genes involved in type IV pilus biogenesis. However, there was not a single (set) of mutation(s) that could invariably be found in all four pairs of strains. Phenotypic assays further showed that these genetic changes were generally not associated with increased serum resistance, higher fitness in human blood ex vivo or differences in the interaction with human epithelial and endothelial cells in vitro. In conclusion, we hypothesize that virulence of meningococci results from accidental emergence of invasive variants during carriage and without within host evolution of invasive phenotypes during disease progression in vivo.
KW  - blood
KW  - comparative genomics
KW  - throat
KW  - genetic loci
KW  - Neisseria meningitidis
KW  - genomic libraries
KW  - genome sequencing
KW  - sequence assembly tools
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159547
VL  - 12
IS  - 1
ER  -