Transcriptional Profiling of Type II Toxin-Antitoxin Genes of Helicobacter pylori under Different Environmental Conditions: Identification of HP0967-HP0968 System
Por:
Cardenas-Mondragon, Maria G., Ares, Miguel A., Panunzi, Leonardo G., Pacheco, Sabino, Camorlinga-Ponce, Margarita, Giron, Jorge A., Torres, Javier, De la Cruz, Miguel A.
Publicada:
22 nov 2016
Resumen:
Helicobacter pylori is a Gram-negative bacterium that colonizes the
human gastric mucosa and is responsible for causing peptic ulcers and
gastric carcinoma. The expression of virulence factors allows the
persistence of H. pylon in the stomach, which results in a chronic,
sometimes uncontrolled inflammatory response. Type II toxin antitoxin
(TA) systems have emerged as important virulence factors in many
pathogenic bacteria. Three type II TA systems have previously been
identified in the genome of pylon 26695: HP0315-HP0316, HP0892-HP0893,
and HP0894-HP0895. Here we characterized a heretofore undescribed type
II TA system in H. pylori, HP0967-HP0968, which is encoded by the
bicistronic operon hp0968-hp0967 and belongs to the Vap family. The
predicted HP0967 protein is a toxin with ribonuclease activity whereas
HP0968 is an antitoxin that binds to its own regulatory region. We found
that all type II TA systems were expressed in H. pylori during early
stationary growth phase, and differentially expressed in the presence of
urea, nickel, and iron, although, the hp0968-hp0967 pair was the most
affected under these environmental conditions. Transcription of
hp0968-hp0967 was strongly induced in a mature H. pylori biofilm and
when the bacteria interacted with AGS epithelial cells. Kanamycin and
chloramphenicol considerably boosted transcription levels of all the
four type II TA systems. The hp0968-hp0967 TA system was the most
frequent among 317 H. pylori strains isolated from all over the world.
This study is the first report on the transcription of type II TA genes
in H. pylori under different environmental conditions. Our data show
that the HP0967 and HP0968 proteins constitute a bona fide type II TA
system in H. pylori, whose expression is regulated by environmental
cues, which are relevant in the context of infection of the human
gastric mucosa.
Filiaciones:
IMSS, Ctr Med Nacl Siglo 21, Hosp Pediat, Unidad Invest Med Enfermedades Infecciosas & Para, Mexico City, DF, Mexico
Aix Marseille Univ UM2, INSERM, U1104, Ctr Immunol Marseille Luminy,CNRS,UMR7280, Marseille, France
Inst Biotecnol UNAM, Dept Microbiol Mol, Cuernavaca, Morelos, Mexico
Benemerita Univ Autonoma Puebla, Ctr Detecc Biomol, Puebla, Mexico
|