Functional profiling in Streptococcus mutans: construction and examination of a genomic collection of gene deletion mutants.

Mol Oral Microbiol
Authors
Keywords
Abstract

A collection of tagged deletion mutant strains was created in Streptococcus mutans UA159 to facilitate investigation of the aciduric capability of this oral pathogen. Gene-specific barcoded deletions were attempted in 1432 open reading frames (representing 73% of the genome), and resulted in the isolation of 1112 strains (56% coverage) carrying deletions in distinct non-essential genes. As S. mutans virulence is predicated upon the ability of the organism to survive an acidic pH environment, form biofilms on tooth surfaces, and out-compete other oral microflora, we assayed individual mutant strains for the relative fitness of the deletion strain, compared with the parent strain, under acidic and oxidative stress conditions, as well as for their ability to form biofilms in glucose- or sucrose-containing medium. Our studies revealed a total of 51 deletion strains with defects in both aciduricity and biofilm formation. We have also identified 49 strains whose gene deletion confers sensitivity to oxidative damage and deficiencies in biofilm formation. We demonstrate the ability to examine competitive fitness of mutant organisms using the barcode tags incorporated into each deletion strain to examine the representation of a particular strain in a population. Co-cultures of deletion strains were grown either in vitro in a chemostat to steady-state values of pH 7 and pH 5 or in vivo in an animal model for oral infection. Taken together, these data represent a mechanism for assessing the virulence capacity of this pathogenic microorganism and a resource for identifying future targets for drug intervention to promote healthy oral microflora.

Year of Publication
2015
Journal
Mol Oral Microbiol
Volume
30
Issue
6
Pages
474-95
Date Published
2015 Dec
ISSN
2041-1014
URL
DOI
10.1111/omi.12107
PubMed ID
25973955
PubMed Central ID
PMC4636983
Links
Grant list
R01 DE017425 / DE / NIDCR NIH HHS / United States
R01 DE013683 / DE / NIDCR NIH HHS / United States
T90 DE-021985 / DE / NIDCR NIH HHS / United States
DE017425 / DE / NIDCR NIH HHS / United States
R01 DE017157 / DE / NIDCR NIH HHS / United States
DE017157 / DE / NIDCR NIH HHS / United States
T90 DE021985 / DE / NIDCR NIH HHS / United States