Figure 4From: Modulatory effects of cAMP and PKC activation on gap junctional intercellular communication among thymic epithelial cellsIncrease in cAMP enhances connexin gene and protein expression. Cultures of the mouse TEC line were treated with either 8-Br-cAMP (1 mM) or forskolin (10 μM) for 6 hrs at 37°C. Cells were then fixed, permeabilized and labeled with the anti-Cx43 polyclonal antibody, ultimately revealed with the Alexa 488-conjugated secondary antibody. The fluorescence microscopy images (A, C, E) and the corresponding phase contrast images are depicted (B, D, F). The mouse TEC treated with 8-Br-cAMP (C, D) and forskolin (E, F) presented an increased punctate labeling of Cx43, mainly at cell-to-cell contact regions, when compared with the untreated controls (A, B). Inserts in A and B show the fluorescence microscopy image and respective phase contrast image of TEC subjected to isotype control primary antibody and Alexa-488-coupled secondary antibody (Magnification, ×400). Panel G show by northern blot analysis that 8-Br-cAMP also enhances Cx43 gene transcription. Mouse TEC were treated or not (Ct) with 8-Br-cAMP (1 mM) and cultured for 1, 6 or 24 hrs at 37°C. The total RNA was then extracted, and 10 - 20 μg of total RNA was loaded in 1.2% agarose gel and plotted onto nylon membrane. For detection of Cx43 mRNA, the membrane was hybridized with a 32P-labeled cDNA probe for Cx43. Alternatively, the membrane was also hybridized with a 32P-labeled cDNA for GAPDH. The amount of Cx43 mRNA in IT-76M1 cells was increased after 1, 6, and 24 hours of treatment with 8-Br-cAMP.Back to article page