Effect of bta-miR-145 over-expression and down-expression on the other microRNA expression in primary bovine mammary epithelial cells
MicroRNA research has made great progress. MicroRNA over-expression by mimic or down-expression by inhibitor is a common method to study the function of microRNA. However, it is unknown that whether over-expression or inhibition of a certain microRNA affects other microRNAs expression or not. This study was carried out to evaluate the effect of bta-miR-145 over-expression or down-expression on other microRNAs expression. Bta-miR-145 mimic (150pmol/ well) or inhibitor (300pmol/ well) was transfected in primary bovine mammary epithelial cells in 6-well plates. After 24h transfection, expressions of bta-miR-145, bta-miR-214, bta-miR-181a, bta-miR-21 were detected by RT-qPCR method. Relative quantification (ΔΔCt) method was used to analyze the data. The geometric mean of 5SrRNA and U6 was used to normalize the expression of microRNAs. All data were tested by one-way ANOVA program of SAS 9.1. The results showed that the over-expression effect of bta-miR-145 was achieved in cells by its mimic, and inhibiting effect of bta-miR-145 was achieved by its inhibitor. In addition, bta-miR-181a and bta-miR-145 had the same expression trend, while bta-miR-214 and bta-miR-145 had the opposite expression trend. And bta-miR-21 expression was almost not affected by bta-miR-145 over-expression and down-expression. It was concluded that one kind of microRNA over-expression or inhibition would cause expression change of other microRNAs. It is suggested that system biology views should be take to explain the related biological problems.
Keywords: bta-miR-145, over-expression, down-expression