Fig. 3. Mist1^KO acinar cells are defective in intercellular communication. (A,B) Isolated acinar cells from wild type (WT) and Mist1^KO mice were processed for Cx32 immunofluorescence (green). Similar to pancreatic sections, WT acinar cultures (A) show Cx32 plaques (arrows) on lateral cell borders whereas Mist1^KO samples (B) exhibit no gap junction staining. Nuclei are stained with the DNA fluorochrome DAPI (blue). (C-H) Pancreatic acini were isolated from WT and Mist1^KO mice, individual acinar cells (arrows) were injected with 10 mM 6-carboxyfluorescein and adjacent cells were monitored for the transfer of dye. Dye transfer to neighboring cells occurs rapidly in WT samples (1 minute, C-D) whereas no transfer is evident in Mist1^KO acinar cells (E-H), even after extended times (20 minutes). C,E,G; phase contrast; D,F,H; fluorescence. (I,J) Pancreatic acini from WT and Mist1^KO mice were analyzed for electrophysiology coupling. Single cells (Cell 1) were injected with 1 M KCl (arrows) and the spread of current was assessed using a recording electrode positioned on adjacent cells (Cell 2). WT (I) acinar cells exhibit normal electrophysiological coupling whereas no coupling is detected in the Mist1^KO cells (J).