Fig. 10. Microinjection of Alexa Fluor 488 fluorescent dye into single cells in thick sections (250 µm) of ear epidermis. (A) Skin section derived from Cx43^Cre-ER(T)/fl mouse after induction with 4-hydroxytamoxifen, photographed under UV light, indicating strongly decreased dye transfer compared with section of wild-type (C57BL/6) mouse (B). Arrows mark the injected cell. Bars, 20 µm. ba, basal layer; de, dermis; la, basal lamina; sb, suprabasal cell layers. (C) Dye transfer in Cx43^Cre-ER(T)/fl epidermis was reduced by 40% compared with several controls (P<0.001). The numbers of mice and injections for each experiment are given in Materials and Methods.