Genes controlling polysaccharide synthesis, protein folding and basic metabolism ensure intra-host cell adaptation and replication of Yersinia enterocolitica

Abstract

Pathogenesis of yersiniosis comprises cell-invasive events in which the bacteria subvert the endocytic-autophagolysosomal pathway of infected host cells to create an intracellular niche for bacterial replication. To determine potential virulence factors that enable intracellular proliferation of Yersinia enterocolitica, we performed a high-throughput transposon-directed insertion site sequencing approach (TraDIS) with infected epithelial HeLa cells. In this screen, we identified seven particular genes that have either metabolic activities in disulfide bond formation (dsbA), glutamine synthesis (glnA), and energy generation (acnB), or dictate synthesis of enterobacterial common antigen ECA (webB/C/F) and LPS (wzx). Individual knockout of the identified genes impaired intracellular replication of Yersinia. Furthermore, these mutants differentially affected host cell autophagy and the acidification of Yersinia-containing vacuoles (YCVs). The results indicate that glnA, acnB, dsbA, wecB, and wecC support autophagy-promoted, intracellular replication of Yersinia. Folding of yet to be defined proteins dependent on dsbA seems to be most critically required for mediating these events. A wzx-controlled LPS synthesis pathway appears implicated in preventing YCV acidification. These results suggest that autophagy induction and adjustment of Yersinia to the intravacuolar environment result from a multifactorial adaptation process that involves formation of a protective carbohydrate envelope and basic metabolic enzymes needed for the refinement of productive intracellular replication.