Diversity of the fsr-gelE region of the Enterococcus faecalis genome but conservation in strains with partial deletions of the fsr operon.

TitleDiversity of the fsr-gelE region of the Enterococcus faecalis genome but conservation in strains with partial deletions of the fsr operon.
Publication TypeJournal Article
Year of Publication2011
AuthorsGalloway-Peña, JR, Bourgogne, A, Qin, X, Murray, BE
JournalAppl Environ Microbiol
Volume77
Issue2
Pagination442-51
Date Published2011 Jan
ISSN1098-5336
KeywordsBacterial Proteins, Bacterial Typing Techniques, Conserved Sequence, Enterococcus faecalis, Gelatinases, Gene Order, Genetic Loci, Genetic Variation, Genotype, Multilocus Sequence Typing, Operon, Sequence Deletion
Abstract

Most Enterococcus faecalis isolates carry gelE, but many are gelatinase nonproducers due to the lack of fsrC (EF_1820) to EF_1841 (fsrC-EF_1841; 23.9 kb in strain V583), including most of the locus encoding Fsr, which activates gelE expression. Analysis of 22 accessible E. faecalis genomes revealed the identity of the 53-amino-acid propeptide of fsrD across multiple MLSTs (multilocus sequence types), although 12 distinctly different variations were found in the EF_1814-to-EF_1902 region. Diversity was seen in fsrABC, in the region EF_1814 to EF_1902, and in a 700-kb region surrounding fsrC-EF_1841. However, analysis of five sequenced strains carrying the fsrC-EF_1841 deletion and the putative integrative conjugative element efaB5 showed almost identical single nucleotide polymorphisms (SNPs) in gelE and an identical junction sequence, despite their unrelated MLSTs, in contrast to those shown by strains without the deletion. Further analysis confirmed the conserved gelE SNPs in 6 additional strains (11 in total) with the deletion. While we were unable to detect evidence of spontaneous deletion using OG1RF and 8 other strains, we were able to engineer a deletion of the 37-kb fsrC-EF_1841 region of OG1RF without deleterious effects, and the 37-kb mutant showed changes in biofilm and chaining similar to those shown by fsr-gelE mutants. In conclusion, we describe the identity of fsrD despite high plasticity within the fsrC-EF_1841 region and the surrounding sequence. However, strains lacking the fsrC-EF_1841 region show a distinct conservation of the sequence surrounding this deletion and in gelE, suggesting that the deletion may result from horizontal transfer and recombination.

DOI10.1128/AEM.00756-10
Alternate JournalAppl. Environ. Microbiol.
PubMed ID21097591
PubMed Central IDPMC3020530
Grant ListR01 AI047923 / AI / NIAID NIH HHS / United States
T32 AI55449 / AI / NIAID NIH HHS / United States
U54 HG003273 / HG / NHGRI NIH HHS / United States
R37 AI47923 / AI / NIAID NIH HHS / United States
T32 AI055449 / AI / NIAID NIH HHS / United States
R37 AI047923 / AI / NIAID NIH HHS / United States