title: Modification of theStreptococcus mutanstranscriptome by LrgAB and environmental stressors.
abstract: TheStreptococcus mutansCid/Lrg system is central to the physiology of this cariogenic organism, affecting oxidative stress resistance, biofilm formation and competence. Previous transcriptome analyses oflytS(responsible for the regulation oflrgABexpression) andcidBmutants have revealed pleiotropic effects on carbohydrate metabolism and stress resistance genes. In this study, it was found that anlrgABmutant, previously shown to have diminished aerobic and oxidative stress growth, was also much more growth impaired in the presence of heat and vancomycin stresses, relative to wild-type,lrgAandlrgBmutants. To obtain a more holistic picture of LrgAB and its involvement in stress resistance, RNA sequencing and bioinformatics analyses were used to assess the transcriptional response of wild-type and isogeniclrgABmutants under anaerobic (control) and stress-inducing culture conditions (aerobic, heat and vancomycin). Hierarchical clustering and principal components analyses of all differentially expressed genes revealed that the most distinct gene expression profiles betweenS. mutansUA159 andlrgABmutant occurred during aerobic and high-temperature growth. Similar to previous studies of acidBmutant,lrgABstress transcriptomes were characterized by a variety of gene expression changes related to genomic islands, CRISPR-C as systems, ABC transporters, competence, bacteriocins, glucosyltransferases, protein translation, tricarboxylic acid cycle, carbohydrate metabolism/storage and transport. Notably, expression oflrgABwas upregulated in the wild-type strain under all three stress conditions. Collectively, these results demonstrate that mutation oflrgABalters the transcriptional response to stress, and further support the idea that the Cid/Lrg system acts to promote cell homeostasis in the face of environmental stress.
authors.affiliation: 1​Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Kelly C
authors.initials: KC
authors.lastname: Rice
authors.affiliation: 1​Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Turner
authors.affiliation: 1​Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.|†​Present address: Department of Health Outcomes and Policy, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: O'neshia V
authors.initials: OV
authors.lastname: Carney
authors.affiliation: 2​Bioinformatics, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Tongjun
authors.initials: T
authors.lastname: Gu
authors.affiliation: 3​Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Ahn
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D018384:Oxidative Stress / Q000235:genetics; D013295:Streptococcus mutans / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D059467:Transcriptome; D015854:Up-Regulation; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D014640:Vancomycin
keywords: LrgAB; S. mutans; heat-shock; oxygen; stress response; vancomycin