title: The Listeria transcriptional landscape from saprophytism to virulence.
abstract: The bacterium Listeria monocytogenes is ubiquitous in the environment and can lead to severe food-borne infections. It has recently emerged as a multifaceted model in pathogenesis. However, how this bacterium switches from a saprophyte to a pathogen is largely unknown. Here, using tiling arrays and RNAs from wild-type and mutant bacteria grown in vitro, ex vivo and in vivo, we have analysed the transcription of its entire genome. We provide the complete Listeria operon map and have uncovered far more diverse types of RNAs than expected: in addition to 50 small RNAs (<500 nucleotides), at least two of which are involved in virulence in mice, we have identified antisense RNAs covering several open-reading frames and long overlapping 5' and 3' untranslated regions. We discovered that riboswitches can act as terminators for upstream genes. When Listeria reaches the host intestinal lumen, an extensive transcriptional reshaping occurs with a SigB-mediated activation of virulence genes. In contrast, in the blood, PrfA controls transcription of virulence genes. Remarkably, several non-coding RNAs absent in the non-pathogenic species Listeria innocua exhibit the same expression patterns as the virulence genes. Together, our data unravel successive and coordinated global transcriptional changes during infection and point to previously unknown regulatory mechanisms in bacteria.
authors.affiliation: Institut Pasteur, Unité des Interactions Bactéries-Cellules, F-75015 Paris, France.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Toledo-Arana
authors.forename: Olivier
authors.initials: O
authors.lastname: Dussurget
authors.forename: Georgios
authors.initials: G
authors.lastname: Nikitas
authors.forename: Nina
authors.initials: N
authors.lastname: Sesto
authors.forename: Hélène
authors.initials: H
authors.lastname: Guet-Revillet
authors.forename: Damien
authors.initials: D
authors.lastname: Balestrino
authors.forename: Edmund
authors.initials: E
authors.lastname: Loh
authors.forename: Jonas
authors.initials: J
authors.lastname: Gripenland
authors.forename: Teresa
authors.initials: T
authors.lastname: Tiensuu
authors.forename: Karolis
authors.initials: K
authors.lastname: Vaitkevicius
authors.forename: Mathieu
authors.initials: M
authors.lastname: Barthelemy
authors.forename: Massimo
authors.initials: M
authors.lastname: Vergassola
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Nahori
authors.forename: Guillaume
authors.initials: G
authors.lastname: Soubigou
authors.forename: Béatrice
authors.initials: B
authors.lastname: Régnault
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Coppée
authors.forename: Marc
authors.initials: M
authors.lastname: Lecuit
authors.forename: Jörgen
authors.initials: J
authors.lastname: Johansson
authors.forename: Pascale
authors.initials: P
authors.lastname: Cossart
mesh_terms: D000818:Animals; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D016680:Genome, Bacterial / Q000235:genetics; D007422:Intestines / Q000382:microbiology; D008089:Listeria monocytogenes / Q000235:genetics* / Q000472:pathogenicity*; D051379:Mice; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics*; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics*; D020506:Untranslated Regions / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D038621:Regulatory Sequences, Ribonucleic Acid; D020506:Untranslated Regions