Fig. 9. Over-expression of ZO-1 increases gap junctional communication and punctate appositional membrane staining for Cx43. (A) Immunofluorescence localization of Cx43 in ROS cells and ROS/ZO-1myc cells with antibodies directed against Cx43, ZO-1 or the myc epitope. Scale bar: 25 µm. (B) Cells were fixed, permeabilized, and simultaneously stained with the Sigma polyclonal antibody directed against Cx43 and a monoclonal antibody directed against ZO-1. The cells were then probed with a CY-3 donkey anti-rabbit IgG and an Alexa 488 goat anti-mouse IgG, and examined with the appropriate fluorescence filters. Scale bar: 25 µm. (C) Over-expression of the ZO-1 increases gap junctional communication in transfected ROS cells. Lucifer Yellow was injected into single cells in confluent monolayers, and the number of dye filled cells was scored after 3 minutes (N=25). Results are expressed as the mean number of dye filled cells per injected cell ± s.d.