Role of the Hedgehog Signaling Pathway in Regulating the Behavior of Germline Stem Cells

Figure 2

Effect of the Hh signaling pathway on the regulation of proliferation and differentiation of OGSCs in Drosophila. (a) OGSCs and their progeny are located in a niche that is composed of various somatic cells. (b) (A) Hh secreted from TFCs and CpCs can promote the self-renewal of OGSCs directly. (B) Hh originating from TFCs and CpCs can promote CpCs and AECs to secrete Gbb or Dpp, which is indirectly beneficial for the self-renewal of OGSCs. (c) (C) COP9 is important for maintaining the activity of the Hh pathway in PECs. The COP and Hh axis helps to prevent Dpp from diffusing. Moreover, COP9 can downregulate Dpp expression in PECs. A low concentration of Dpp antagonizes OGSC progeny differentiation.

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