尚　丹　李美红　许　馨　曹山虎　孙绍光1.北京铁路局石家庄卫生防疫站，河北石家庄050000；2.山东省招远市人民医：药剂科，山东招远265400；.河北医科大学基础医学：生物化学与分子生物学教研室，河北石家庄050017

m iR-342-3p抑制SM 22α启动子的转录活性

尚丹1*李美红2*许馨3曹山虎3孙绍光3
1.北京铁路局石家庄卫生防疫站，河北石家庄050000；2.山东省招远市人民医：药剂科，山东招远265400；3.河北医科大学基础医学：生物化学与分子生物学教研室，河北石家庄050017

目的探究miR-342-3p是否通过作用于SM22α启动子，从转录水平调控SM22α的表达。方法通过软件RNAhybrid分析发现，大鼠SM22α启动子中存在一个miR-342-3p的识别位点。将miR-342-3pmimics与报告基因载体pGL3-SM22α-Promoter共转染293A细胞，通过检测荧光素酶活性来分析miR-342-3p对SM22α启动子转录活性的影响。将miR-342-3p mimics转染血管平滑肌细胞，采用qRT-PCR和Western blot分别检测SM22α mRNA和蛋白质水平，分析miR-342-3p对血管平滑肌细胞中SM22α表达的影响。结果与miR-control相比，miR-342-3p能够使SM22α启动子转录活性降低（0.54±0.03）倍，差异有统计学意义（P＜0.05）；与miR-control相比，miR-342-3p能够使血管平滑肌细胞中SM22αmRNA水平降低（0.45±0.04）倍，SM22α蛋白质水平下降（0.41± 0.05）倍，差异有统计学意义（P＜0.05）。结论miR-342-3p通过抑制SM22α启动子活性，从转录水平降低SM22α的表达，为miRNA调控血管平滑肌细胞表型转化研究提供了新角度。

microRNA；miR-342-3p；SM 22α；启动子

［Avsteact］Ov jective To explore whethermiR-342-3p could repress the expression of SM22αat the transcriptional level by targeting its promoter.M ethods Therewas a potential binding site ofmiR-342-3p in the SM22αpromoter analyzed by using RNAhybrid software.293A cells were co-transfected with miR-342-3p mimics and pGL3-SM22α-Promoter reporter gene vectors，luciferase activity was detected to analyze whether the SM22αpromoter activity is repressed bymiR-342-3p.Vascular smoothmuscle cellswere transfected withmiR-342-3p mimics，SM22αmRNA and protein levelswere detected by using qRT-PCR and Western blot，to explore the influence ofmiR-342-3p on the expression of SM22αin vascular smooth muscle cells.Results Compared with miR-control，SM22αpromoter transcriptional activity was reduced（0.54±0.03）folds bymiR-342-3p，the difference was statistically significant（P＜0.05）.The SM22αmRNA in vascular smooth muscle cellswas decreased（0.45±0.04）folds，and the SM22αprotein levelwas decreased（0.41±0.05）folds bymiR-342-3p，compared withmiR-control，the differenceswere statistically significant（P＜0.05）.Conclusion miR-342-3p represses the expression of SM22αat the transcriptional level by targeting its promoter，which provides a novel perspective for the study ofmiRNA in vascular smooth muscle cell phenotypic switch regulation.

［Key woeds］microRNA；miR-342-3p；SM22α；Promoter

microRNA（miRNA）是一类内源性的、长约22个核苷酸的调控性非编码RNA。miRNA的主要作用模式是通过碱基不完全互补配对的方式介导RNA诱导沉默复合体（RNA-induced silencing complex，RISC）与胞质中靶mRNA的3'UTR结合，从转录后水平抑制靶基因的翻译［1］。值得关注的是，成熟miRNA不但分布在细胞质中，还广泛分布在细胞核内，并且很多miRNA在核内的浓度远高于在胞质中的浓度［2-3］。……