Abstract: The study was aimed to investigate the molecular mechanisms of miR-193a inducing apoptosis in cytopathogenic bovine virus diarrhea virus (cp BVDV) infected MBDK cells. Prediction of apoptosis-related miR-193a target gene Bax with bioinformatics online applications,TargetScan and Microcosm Targets,and verification of the interaction between miR-193a and Bax by dual-luciferase reporter assay were carried out to investigate the interaction between miR-193a and Bax. miR-193a overexpressing lentivirus pre-miR-193a-lv and lentivirus pre-miR-193a-inhibitor-lv inhibiting miR-193a expression were used to infect MDBK cells,respectively;Bax expression levels and apoptosis rates of MDBK cells were detected by Real-time quantitative PCR,Western blotting and flow cytometry,48 h later. According to the prediction and verification,we convinced that apoptosis-related gene Bax was the target of miR-193a;the results of Real-time quantitative PCR,Western blotting and dual-luciferase reporter assay showed that miR-193a directly targeted the miRNA response site of Bax 3'UTR and Bax expression levels were extremely significantly downregulated after miR-193a overexpression (P<0.01);meanwhile,the results of flow cytometry assay showed that apoptosis rates were extremely significantly decreased in MDBK cells infected with pre-miR-193a-lv (P<0.01). In a word,miR-193a could directly target Bax gene in pathway of apoptosis and promot apoptosis.

Key words: miR-193a; Bax; apoptosis; MDBK cells