南方医科大学学报

南方医科大学学报 ›› 2021, Vol. 41 ›› Issue (11): 1725-1732.doi: 10.12122/j.issn.1673-4254.2021.11.19

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Srn821798在变异链球菌变链素IV形成中的作用

徐 丽，刘姗姗，王 敏，刘 芳，张容秀，张 凯   

  1. 蚌埠医学院第一附属医院口腔科，安徽 蚌埠 233004；蚌埠医学院第二附属医院口腔科，安徽 蚌埠 233040
  • 出版日期:2021-11-20 发布日期:2021-12-10

Regulatory role of small RNA srn821978 in mutacin IV expression in Streptococcus mutans

XU Li, LIU Shanshan, WANG Min, LIU Fang, ZHANG Rongxiu, ZHANG Kai   

  1. Department of Stomatology, First Affiliated Hospital of Bengbu Medical College, Bengbu233004, China; Department of Stomatology, Second Affiliated Hospital of Bengbu Medical College, Bengbu233040, China
  • Online:2021-11-20 Published:2021-12-10

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摘要： 目的 分析 srn821798 对变链素Ⅳ的影响，探索变链素Ⅳ转录后的规律。方法 用靶基因预测软件 RNAhybrid、RNAPredator和IntaRNA对srn821798进行靶基因预测，继而采用抑菌圈实验筛选了高表达变链素Ⅳ的变异链球菌菌株和不表达变链素Ⅳ的变异链球菌菌株各10株，并采用qPCR技术检测了这些菌株中srn821798和候选靶基因的表达水平。体外合成srn821798模拟物和抑制剂，采用电转化的方法在变异链球菌UA159标准株中构建了srn821798高表达株和低表达株，分析和比较这些菌株中srn821798和候选靶基因的表达水平。最后通过电泳和双荧光素酶报告基因实验检测了srn821798和候选靶基因sepM预测作用位点的结合能力。采用SPSS20.0软件包对数据进行统计学分析。结果 变异链球菌临床菌株中高表达变链素Ⅳ组中的候选靶基因sepM，comD，comE，nlmA及nlmB的表达水平均显著高于无表达变链素Ⅳ组，而高表达变链素Ⅳ组srn821798的表达水平显著低于无表达变链素Ⅳ组（P<0.05）。虽然标准株中srn821798上调组和下调组中候选靶基因的表达水平差异不大，但 sepM 的表达水平存在差异分布的趋势，并且预测的 srn821798 与 sepM 作用位点的结合能力较高。结论 srn821798可能在变链素Ⅳ的形成中起着一定的调控作用，但机制有待进一步探索。

关键词: 变异链球菌；变链素Ⅳ；sRNAs；sepM

Abstract: Objective To analyze the role of small RNA srn821978 in posttranscriptional regulation of mutacin IV expression in Streptococcus mutans. Methods The potential target genes of srn821798 were predicted using RNAhybrid, RNAPredator and IntaRNA. We collected 10 Streptococcus mutans (S.muans) strains with high expression of mutacin IV and another 10 S.muans strains that did not express mutacin IV screened by inhibition zone test, and the expression levels of srn821798 and the candidate target genes in these strains were detected by qPCR. Using synthesized mimics and inhibitors of srn821798, we constructed S.muans strains with high or low srn821798 expression via electroporation based on the standard strain of S.muans UA159, and analyzed the expression levels of srn821798 and its candidate target genes in these strains. We also examined the binding ability of srn821798 to its target gene sepM using electrophoresis and a dual-luciferase reporter system. Results The expression levels of the candidate target genes of srn821798 including sepM, comD, comE, nlmA and nlmB were significantly higher while the expression level of srn821798 was significantly lower in clinical S.muans strains with high expression of mutacin IV than in those without mutacin IV expression (P<0.05). Although the expression levels of the candidate target genes in strains with up- regulated or down- regulated srn821798 expression did not differ significantly from those in the standard strain, the expression level of sepM showed a trend of differential distribution, and srn821798 was predicted to have a strong binding ability to sepM action site. Conclusion srn821798 may play a regulatory role in the expression of mutacin IV in S.muans, but the underlying mechanism remains to be explored.

Key words: Streptococcus mutans; mutacin IV; sRNAs; sepM