Figure 4. mTOR was a direct target of miR-503. A. The predicted miR-503 binding sites on mTOR. B. Luciferase activity in HEK293T cells co-transfected with miR-503 mimics, miR-503 inhibitor and luciferase reporters containing mTOR wild type or mutant type (MUT) 3´-UTR. Histogram indicates the values of luciferase measured 48 h after transfection. **p < 0.01 vs. mimic NC group; ##p < 0.01 vs. inhibitor NC group. C and D. miR-503 mimics, miR-503 inhibitor and controls were transfected into INS-1 cells, then the mRNA and protein levels of mTOR were detected by qRT-PCR and Western Blot. **p < 0.01 vs. mimic NC or inhibitor NC group. E. The expression level of mTOR in peripheral blood samples from 25 pairs of GDM pregnancies and healthy pregnancies was detected by using qRT-PCR. **p < 0.01 vs. Normal group. F. Pearson's correlation analysis of the relationship between miR-503 expression and mTOR expression in peripheral blood samples from 25 pairs of GDM pregnancies (r =0-0.7757, p < 0.01).