PMID:26406329

Citation	Beltrame, CO, Côrtes, MF, Bonelli, RR, Côrrea, AB, Botelho, AM, Américo, MA, Fracalanzza, SE and Figueiredo, AM (2015) Inactivation of the Autolysis-Related Genes lrgB and yycI in Staphylococcus aureus Increases Cell Lysis-Dependent eDNA Release and Enhances Biofilm Development In Vitro and In Vivo. PLoS ONE 10:e0138924
Abstract	Staphylococcus aureus ica-independent biofilms are multifactorial in nature, and various bacterial proteins have been associated with biofilm development, including fibronectin-binding proteins A and B, protein A, surface protein SasG, proteases, and some autolysins. The role of extracellular DNA (eDNA) has also been demonstrated in some S. aureus biofilms. Here, we constructed a Tn551 library, and the screening identified two genes that affected biofilm formation, lrgB and yycI. The repressive effect of both genes on the development of biofilm was also confirmed in knockout strains constructed by allelic recombination. In contrast, the superexpression of either lrgB or yycI by a cadmium-inducible promoter led to a decrease in biofilm accumulation. Indeed, a significant increase in the cell-lysis dependent eDNA release was detected when lrgB or yycI were inactivated, explaining the enhanced biofilm formed by these mutants. In fact, lrgB and yycI genes belong to distinct operons that repress bacterial autolysis through very different mechanisms. LrgB is associated with the synthesis of phage holin/anti-holin analogues, while YycI participates in the activation/repression of the two-component system YycGF (WalKR). Our in vivo data suggest that autolysins activation lead to increased bacterial virulence in the foreign body animal model since a higher number of attached cells was recovered from the implanted catheters inoculated with lrgB or yycI knockout mutants.
Links	PubMed PMC4583396 Online version:10.1371/journal.pone.0138924
Keywords	Animals; Bacterial Proteins/genetics; Bacteriolysis; Biofilms/growth & development; DNA, Bacterial/metabolism; Disease Models, Animal; Gene Expression Regulation, Bacterial; Gene Library; Humans; In Vitro Techniques; Mice; Mutagenesis, Insertional; Staphylococcal Infections/genetics; Staphylococcal Infections/microbiology; Staphylococcus aureus/genetics; Staphylococcus aureus/isolation & purification; Staphylococcus aureus/physiology; Virulence Factors/genetics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STAA8:LRGB		GO:1900231: regulation of single-species biofilm formation on inanimate substrate	ECO:0000315:		P		In Figure 1A it is shown that when knocking out the gene LrgB, biofilm production on an inert polystyrene surface greatly increased, showing that LrgB has a role in the regulation of biofilm production.	complete CACAO 12667
STAA8:Q2G2U2		GO:1900231: regulation of single-species biofilm formation on inanimate substrate	ECO:0000315:		P		In Figure 1C it is shown that when knocking out the gene YycL, biofilm production on an inert polystyrene surface greatly increased, showing that YycL has a role in the regulation of biofilm production.	complete CACAO 12668

References

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