miR-1306 Mediates the Feedback Regulation of the TGF-ß/SMAD Signaling Pathway in Granulosa Cells

Yang, Liu; Du, Xing; Liu, Lu; Cao, Qiuyu; Pan, Zengxiang; Li, Qifa

Further, we detected the levels of a downstream member of the classical TGF-β/SMAD pathway, p-SMAD3, which also acts as a marker for the pathway in porcine GCs. miR-1306 mimics or miR- Our previous study demonstrated that the TGFBR2 gene is directly targeted by miR-1306 in porcine GCs [9] . To evaluate whether TGFBR2 is a functional target of miR-1306, we overexpressed and silenced the endogenous miR-1306 level in porcine GCs cultured in vitro by treating with both miR-1306 mimics and miR-1306 inhibitors (Supplementary Figure S4) . qRT-PCR and Western blotting results proved that overexpression of miR-1306 significantly reduced the TGFBR2 mRNA ( Figure 1C ) and protein levels in GCs ( Figure 1D ). On the other hand, when miR-1306 was silenced in porcine GCs, the opposite result was seen ( Figure 1E ,F). In addition, the miR-1306 level was found to be negatively correlated with TGFBR2 mRNA level in the follicles of porcine ovaries ( Figure 1G ). These results suggest that miR-1306 targets the TGFBR2 3 -UTR in porcine GCs.