Fig. 9

Proposed hypothetical model depicting the involvement of miR-424/503 cluster in the Activin signalling pathway by targeting SMAD7. Increased expression of miR-424/503 cluster suppresses the expression of SMAD7 which eventually increases the phosphorylation of SMAD2/3 and subsequently promotes the granulosa cell proliferation and cell cycle progression. Thus, when granulosa cells are treated with Activin A, the SMAD7 expression is suppressed, but the ACVR2A expression was maintained and leading to enhanced cell proliferation. At the time when the cells reach peak proliferation activity, the miR-424/503 expression was suppressed indicating the presence of negative feed back loop between the expression of miR-424/503 and cell proliferation activity in Activin A treated cells