title: Disentangling competence for genetic transformation and virulence in Streptococcus pneumoniae.
abstract: Horizontal gene transfer mediated by the competence regulon is a major driver of genome plasticity in Streptococcus pneumoniae. When pneumococcal cells enter the competent state, about 6% of the genes in the genome are up-regulated. Among these, some genes are essential for genetic transformation while others are dispensable for the process. Exhaustive deletion analyses show that some up-regulated genes dispensable for genetic transformation contribute to pneumococcal-mediated pneumonia and bacteremia infections. Interestingly, virulence functions of such genes are either dependent or independent of the competent state. Among the competent-state-dependent genes are those mediating allolysis, a process where small fraction of non-competent cells within the pneumococcal population are lysed by their competent counterparts, releasing DNA presumably for transformation. Inadvertently, the pore-forming toxin pneumolysin is also released during allolysis, contributing to virulence. In this review, we discuss recent advances in our understanding of pneumococcal virulence processes mediated by the competence regulon. We proposed that coupling of competence induction and bacterial fitness drives the natural selection to favor an intact competence regulon, which in turn, provides the long-term benefits of genetic plasticity.
authors.affiliation: Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Jingjun
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.|Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA.
authors.forename: Luchang
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA. geelau@illinois.edu.
authors.forename: Gee W
authors.initials: GW
authors.lastname: Lau
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D006801:Humans; D009154:Mutation; D009876:Operon; D011995:Recombination, Genetic; D013296:Streptococcus pneumoniae / Q000472:pathogenicity / Q000502:physiology*; D013301:Streptolysins / Q000235:genetics / Q000378:metabolism; D014169:Transformation, Bacterial; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae
keywords: Allolysis; Competence; Pneumolysin; Streptococcus pneumoniae; Virulence