DRP1 down-regulation inhibits Notch-driven differentiation of PFCs in a Marf-1–dependent manner. (A, top) S8 egg chamber with drp1^KG PFC clones (CD8GFP label) do not express Hnt, whereas background PFCs (lacking the CD8GFP label) show Hnt labeling. (second row) drp1^KG PFC clones (CD8GFP label) in constitutive HA-DRP1 background express Hnt. (third row) drp1^KG + Marf-1 RNAi PFC clones (CD8GFP label) show patches of Hnt-positive cells. (bottom) Marf-1 RNAi clones alone (green) show Hnt labeling. Hoechst stains DNA. (B) Comparison of clustered mitochondrial phenotypes seen in drp1^KG PFC clones (CD8GFP positive) with fragmented mitochondria (HSP-60) appearing in neighboring nonclonal cells in an S10 egg chamber. (C) Marf-1 RNAi expression (CD8GFP) causes clustered mitochondria (HSP-60) of MBCs in an S8 egg chamber to fragment. Hoechst stains nuclei. See Fig. S1 E for Marf-1 RNAi clones in S10 with the same phenotype. (D) drp1^KG PFC clones (CD8GFP positive) show massive retention of NICD in the follicle cell plasma membrane of an S8 egg chamber. (E) drp1^KG PFC clones (CD8GFP positive) show increased Cut labeling compared with the wild-type PFCs in the S8 egg chamber. (F) drp1^KG + Marf-1 RNAi clones (bottom; CD8GFP positive) show significant loss of membrane NICD in the S8 egg chamber when compared with drp1^KG clones (top). (G) PFC clones containing activated Notch (N-Act) and drp1^KG in the S8 egg chamber (middle) show patches of Hnt-positive cells within the multilayer mass of follicle cells, suggesting that N-Act expression can partially override the block in differentiation (i.e., lack of Hnt) seen in drp1^KG clones (top). (bottom) PFC clones expressing N-Act alone express Hnt and do not overproliferate. The white lines define the clone boundary, and the dotted lines outline the egg chambers. Bars, 10 µm.