title: The rnc Gene Promotes Exopolysaccharide Synthesis and Represses the vicRKX Gene Expressions via MicroRNA-Size Small RNAs in Streptococcus mutans.
abstract: Dental caries is a biofilm-dependent disease that largely relies on the ability of Streptococcus mutans to synthesize exopolysaccharides. Although the rnc gene is suggested to be involved in virulence mechanisms in many other bacteria, the information regarding it in S. mutans is very limited. Here, using deletion or overexpression mutant assay, we demonstrated that rnc in S. mutans significantly positively regulated exopolysaccharide synthesis and further altered biofilm formation. Meanwhile, the cariogenecity of S. mutans was decreased by deletion of rnc in a specific pathogen-free (SPF) rat model. Interestingly, analyzing the expression at mRNA level, we found the downstream vic locus was repressed by rnc in S. mutans. Using deep sequencing and bioinformatics analysis, for the first time, three putative microRNA-size small RNAs (msRNAs) targeting vicRKX were predicted in S. mutans. The expression levels of these msRNAs were negatively correlated with vicRKX but positively correlated with rnc, indicating rnc probably repressed vicRKX expression through msRNAs at the post-transcriptional level. In all, the results present that rnc has a potential role in the regulation of exopolysaccharide synthesis and can affect vicRKX expressions via post-transcriptional repression in S. mutans. This study provides an alternative avenue for further research aimed at preventing caries.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Meng-Ying
authors.initials: MY
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Ying-Ming
authors.initials: YM
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan UniversityChengdu, China; Department of Dentistry, Yan'an Hospital Affiliated to Kunming Medical UniversityKunming, China.
authors.forename: Ke-Zeng
authors.initials: KZ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences Chengdu, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Tao
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Jia-Xin
authors.initials: JX
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan UniversityChengdu, China; Department of Endodontics and Operative Dentistry School of Stomatology, Capital Medical UniversityBeijing, China.
authors.forename: Ru
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences Chengdu, China.
authors.forename: Xin-Rong
authors.initials: XR
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University Chengdu, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
keywords: Streptococcus mutans; dental caries; exopolysacchrides; microRNA-size small RNAs; post-transcriptional regulation; rnc gene; vicRKX