Cx43-driven β-Gal immunoreactivity occurs even in the absence of Cre immunoreactivity in mice with germ-line deletion.

A–H: Immunofluorescence analysis for Cre expression (green) and β-Gal (red). Hoechst staining in blue. A, C, E, G: Cerebellum. B, D, F, H: Hippocampus. A, B: WT mice express neither β-Gal nor Cre protein. C,D: Cx30^-/- mice show moderate β-Gal expression in cerebellum and very weak expression in hippocampus. E, F: Cx43^fl/del mice exhibit strong immunoreactivity for β-Gal in both brain areas, but no Cre expression. G, H: DKO mice show β-Gal immunoreactivity essentially identical to mice with ectopic deletion and prominent expression of Cre in both brain areas. Bar: 100 µm (50 µm for F and H).