srtA基因调节变异链球菌氧化耐受的机制研究  

Mechanism research of srtA gene on the oxidation tolerance of Streptococcus mutans

作　　者：何远丽 任彪[1] 陈璇 邹玲[2] HE Yuanli;REN Bi-ao;CHEN Xuan;ZOU Ling(State Key Laboratory of Oral Diseases&National Clinical Research Center for Oral Diseases&West China Hospital of Stomatology,Sichuan University,Chengdu 610041,China;State Key Laboratory of Oral Diseases&National Clinical Research Center for Oral Diseases&Department of Conservative Dentistry and Endodontics,West China Hospital of Stomatology,Sichuan University,Chengdu 610041,China.)

机构地区：[1]口腔疾病研究国家重点实验室,国家口腔疾病临床医学研究中心,四川大学华西口腔医院,四川成都610041 [2]口腔疾病研究国家重点实验室,国家口腔疾病临床医学研究中心,四川大学华西口腔医院牙体牙髓病科,四川成都610041

出　　处：《口腔疾病防治》2020年第5期292-297,共6页Journal of Prevention and Treatment for Stomatological Diseases

基　　金：国家自然科学基金项目(81570974)。

摘　　要：目的探究srtA基因对变异链球菌氧化耐受能力的调节作用并初步探讨其机制。方法通过氧化耐受实验,对比变异链球菌UA159菌株及其srtA基因缺失株及回复株在浮游及生物膜状态下的氧化耐受能力差异;用Illumina Hiseq 4000测序平台对UA159菌株及其srtA基因缺失株在对数中期及稳定期的基因转录组测序,比较其氧化耐受相关基因的转录表达差异,进一步探讨srtA基因缺失后变异链球菌氧化耐受能力的变化与其基因转录组的内在联系;并采用qPCR来验证相关基因表达水平的变化。结果srtA基因缺失后变异链球菌在浮游状态、生物膜状态的氧化耐受能力均较UA159降低(P<0.05)。分析33个氧化耐受相关基因在转录组测序结果中的表达水平发现,过氧化物合成与代谢相关酶类基因无明显变化,但稳定期样本中双组份信号转导系统编码基因lrgA、lrgB、lytT表达下调2.2~2.4倍;qPCR结果进一步表明对数中期、稳定期的浮游菌lrgB、lytT表达下调11.01~53.51倍,且另一双组分系统编码基因vicK表达下调6.57~10.88倍(P<0.001)。结论srtA基因缺失后,变异链球菌过氧化物合成及代谢酶类编码基因表达水平不变,但氧化耐受相关转录调节因子表达水平下降,进而减弱变异链球菌的氧化耐受能力。Objective To investigate the effects of srtA on the oxidation tolerance of the Streptococcus mutans UA159 strain and to explore the potential mechanism.Methods The oxidation tolerance in the planktonic state and biofilm state were compared among UA159,the srtA-deleted strain and the complementary strain through oxidative tolerance experiments.The RNA-sequencing data from both the exponential and stationary phases of UA159 and the srtA-deleted strain were obtained by using the Illumina HiSeq 4 000 sequencing platform to determine the impact of srtA knockout on S.mutans genomic transcription.We compared the differences in the transcriptional expression of oxidative tolerance-related genes between the UA159 strain and the srtA gene deletion strain and further explored the intrinsic relationship between the changes in oxidative tolerance and the genetic transcriptome.qPCR was used to verify the changes in the expression level of oxidation tolerance-related genes.Results The oxidation tolerance of the srtA-deleted strain decreased significantly in both the planktonic state and the biofilm state compared to that of UA159(P <0.05).A total of 33 oxidation tolerance-related genes were differentially expressed according to transcriptome sequencing.There was no significant change in the expression of peroxide synthesis-and metabolic-related enzyme genes,but in the stationary phase samples,the two-component signal transcription systems IrgA,IrgB,and lytT were significantly downregulated(2.2-to 2.4-fold) in the srtA-deleted strain.qPCR further confirmed that in both the exponential and stationary phases,lrgB and lytT expression in the planktonic state was reduced 11.01-53.51-fold,while the expression of the other twocomponent system-encoding gene vicK was reduced by 6.57-10.88-fold(P <0.001).Conclusion Srt A gene deletion did not change the expression level of peroxide synthesis-related and metabolic enzyme-encoding genes but downregulated the expression of the associated transcription regulation factors to reduce the oxidati

关 键 词：变异链球菌 龋病 生物膜 分选酶A srtA基因 氧化应激 氧化耐受 活性氧 转录组测序 双组份信号转导系统 

分 类 号：R780.2[医药卫生—口腔医学]