COL4A3基因3'UTR双荧光素酶报告基因载体构建及其与miR-299靶向关系验证

Construction of Dual-luciferase reporter gene vector of 3'UTR of the COL4A3 gene and validation of its targeting relationship with miR-299

目的探讨双荧光素酶报告基因载体构建并鉴定微小RNA-299(miR-299)与Ⅳ型胶原α3链(COL4A3)基因的靶标关系,为miR-299调控COL4A3基因影响干细胞成软骨分化研究奠定基础.方法2018年3月至2018年12月,利用生物信息学方法预测miR-299与COL4A3-3'UTR区(3'端非翻译区)的潜在结合位点,并通过PCR法扩增COL4A3-3'UTR野生和突变序列,将其克隆至psiCHECK-2质粒中构建相应载体,载体鉴定采用酶切法和基因测序法.细胞复苏、扩增并转染,转染分4组,每组3孔,分别为:①COL4A3-WT加miR-299/NC.②COL4A3-WT加miR-299-inhibitor/NC-inhibitor.③COL4A3-MUT加miR-299/NC.④COL4A3-MUT加miR-299-inhibitor/NC-inhibitor;采用双荧光素酶检测试剂盒测定各组荧光素酶活性并行t检验比较组间差异,P<0.05为差异有统计学意义.结果酶切及DNA测序结果显示psiCHECK-2-COL4A3双荧光素酶报告基因载体构建成功.Luciferase检测显示:野生型COL4A3基因组间比较,miR-299转染组(R/F均值为59.38%)较NC组(R/F均值为100%)荧光素酶活性下降,组间差异有统计学意义(P<0.05);野生型COL4A3基因加inhibitor后组间比较,miR-299-inhibitor组(R/F均值为153.98%)较NC-inhibitor组(R/F均值为100%)荧光素酶活性上升,组间差异有统计学意义(P<0.05);突变型COL4A3基因组及突变型组加入inhibitor后组间比较,miR-299转染组(R/F均值为102.09%)及miR-299-inhibitor组(R/F均值为108.51%)较对应NC组(R/F均值为104.70%)及NC-inhibitor组(R/F均值为105.13%)比较,荧光素酶活性差异均无统计学意义(P>0.05).结论COL4A3基因3'UTR双荧光素酶报告基因载体构建成功,并通过双荧光素酶实验进一步验证了miR-299直接作用于靶基因COL4A3-3'UTR区域的真实性.

Objective To construct a dual-luciferase reporter gene vector and validate the targeting relation ship between miR-299 and the COL4A3 gene,laying a foundation for the study on the effect of miR-299 in the chondrogenic differentiation of stem cells by regulating the COL4A3 gene.Methods This study was made from March,2018 to December,2018.Firstly,the potential binding sites between miR-299 and COL4A3-3'UTR were pre dicted using bioinformatics.Then,the wild and mutant COL4A3-3'UTR sequences were amplified by PCR and cloned into psiCHECK-2 plasmid to construct corresponding recombinant vectors.The vectors were validated by enzyme digestion and gene sequencing.Finally,the cells were resuscitated,amplified,transfected and divided into 4 groups:COL4A3-WT+miR-299/NC group,COL4A3-WT+miR-299-inhibitor/NC-inhibitor group,COL4A3-MUT+miR-299/NC group and COL4A3-MUT+miR-299-inhibitor/NC-inhibitor group.Each group contains 3 holes,respectively.Luciferase activity in each group was determined using a dual-luciferase assay kit.The statistical analysis was conducted and differences between groups were compared by t test.Probabilities lower than 5%(P<0.05) were considered statistically significant.Results Enzyme digestion and DNA sequencing showed that the dual-luciferase reporter gene vector of psiCHECK-2-COL4A3 was constructed successfully.Luciferase assay demonstrated that in wild COL4A3 gene,luciferase activity reduced in the miR-299 transfection group (The average R/F value was 59.38%) compared with the NC group (The average R/F value was 100.00%),with a statistical significant difference (P<0.05).In wild COL4A3 gene treated with inhibitor,luciferase activity increased in the miR-299-inhibitor group (The average R/F value was 153.98%) compared with the NC-inhibitor group (The average R/F value was 100.00%),with a statistical significant difference (P<0.05).In mutant COL4A3 gene treated with inhibitor,no obvious statistical differences in luciferase activity were found between miR-299 transfection group (The average R/F value was 102.09%),miR-299-inhibitor group (The average R/F value was 108.51%) and NC group (The average R/F value was 104.70%),NC-inhibitor group (The average R/F value was 105.13%) and/9>0.05.Conclusion The dual-luciferase reporter gene vector of the 3'UTR of the COL4A3 gene is constructed successfully.In addition,dual-luciferase assay further verifies the authenticity of miR-299 directly targeting the 3'UTR of the COL4A3 gene.